# Boeing Alert Requirements Bulletin 777-53A0091 RB: No revision named

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- Title as filed: FAA-2019-0603 RB-777-53A0091-00 RB - BOEING
- Pages: 90
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### Page 1

Commercial 
Airplanes
777
Requirements Bulletin
ALERT
Number: 777-53A0091 RB
Original Issue: April 08, 2019
ATA System: 5333 5343 5363
SUBJECT: FUSELAGE - Structure Sections 43, 44, and 46 - Circumferential Splice Inspection
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
Copyright © 2019 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
Original Issue: April 08, 2019
777-53A0091 RB
1 of 90
2.0

### Page 2

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
2 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT
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### Page 3

Table of Contents
1 . E F F E C T I V I T Y  ................................................ 5
A. Airplanes ................................................ 5
B . S p a r e s  A f f e c t e d  ............................................ 6
2. CONCURRENT REQUIREMENTS ..................................... 6
3 . C O M P L I A N C E  ................................................ 6
4. APPROVAL ................................................ 1 9
5. ACCOMPLISHMENT INSTRUCTIONS .................................. 2 1
A. General Information ......................................... 2 1
B. Work Instructions ........................................... 2 2
FIGURE 1: STATION (STA) 655 - STRINGERS S-20L TO S-20R INSPECTIO N [Group 1-2, 5, 7] . . 43
FIGURE 2: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-15R TO S-20R INSPECTION [Group
3 ]  ................................................ 4 7
FIGURE 3: STATION (STA) 655 - STRINGERS S-20L TO S-6L AND S-6R T O S-20R INSPECTION [Group
4 ]  ................................................ 5 1
FIGURE 4: STATION (STA) 655 - STRINGERS S-2L TO S-5L INSPECTION [ G r o u p  1 0 ]  ....... 5 5
FIGURE 5: STATION (STA) 655 - STRINGERS S-13L TO S-13R INSPECTIO N [Group 11] ...... 5 9
FIGURE 6: STATION (STA) 655 - STRINGERS S-13L TO S-6L AND S-6R T O S-13R INSPECTION [Group
1 2 ]  ................................................ 6 3
FIGURE 7: STATION (STA) 825+210 - STRINGERS S-13L TO S-13R INSPE CTION [Group 2-3, 5-8] . 67
FIGURE 8: STATION (STA) 825+210 - STRINGERS S-13L TO S-6L AND S- 6R TO S-13R INSPECTION
[Group 4] ............................................ 7 1
FIGURE 9: STATION (STA) 1434+189 - STRINGERS S-13L TO S-13R INSP ECTION [Group 5-6, 9] . 75
FIGURE 10: STATION (STA) 1434+189 - STRINGERS S-13L TO S-6L AND S-6R TO S-13R INSPECTION
[Group 7] ............................................ 7 9
FIGURE 11: STATION (STA) 1832 - STRINGERS S-13L TO S-13R INSPECT I O N  [ G r o u p  5 - 7 ]  ..... 8 3
FIGURE 12: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-14R TO S-20R INSPECTION [Group
6 ]  ................................................ 8 7
Export Controlled ECCN: 9E991
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 4

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
4 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT
BLANK PAGE

### Page 5

Commercial 
Airplanes
777
Requirements Bulletin
ALERT
Number: 777-53A0091 RB
Original Issue: April 08, 2019
ATA System: 5333 5343 5363
SUBJECT: FUSELAGE - Structure Sections 43, 44, and 46 - Circumferential Splice Inspection
THIS DOCUMENT IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN
PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE
NEW OWNER. THIS IS AN ENHANCED REQUIRED FOR COMPLIANCE DOCUMENT. THE BOEING
PROCESSES USED TO CREATE THE SERVICE BULLETIN (SB) AND THE REQUIREMENTS BULLETIN
(RB) ENSURE THAT THE INFORMATION BETWEEN "RC START" AND "RC END" IN THE SB ARE IDENTICAL
TO THE INFORMATION IN THE SAME SECTIONS (COMPLIANCE, WORK INSTRUCTIONS…) OF THE RB
WHICH THE SB REFERS TO AS THE RELATED DOCUMENT.
1. EFFECTIVITY
A. Airplanes
This bulletin is applicable to 777-300ER, 777F Airplane(s), line number(s) 1386, 1398, 1406, 1428,
1434, 1440, 1442, 1444, 1446, 1448, 1450, 1452, 1470, 1472, 1474, 1476, 1478, 1480, 1482, 1484,
1486-1521, 1523-1541 in 12 Group(s).
DESCRIPTIONCONFIGURATIONGROUP
777-300ER airplanes, line number: 1386.-1
777-300ER airplanes, line numbers:1428, 1434, 1442, 1492, 1493,
1494, 1495, 1496, 1497, 1498, 1499, 1501, 1502, 1503, 1504, 1505,
1507, 1509, 1510, 1511, 1512, 1513, 1515, 1517, 1519, 1527, and
1529.
-2
777-300ER airplanes, line numbers: 1521 and 1523.-3
777-300ER airplanes, line numbers: 1482, 1484, 1486, 1487, 1488,
1489, 1490, and 1491.
-4
777-300ER airplanes, line numbers: 1500, 1506, 1508, 1514, 1516,
1518, 1533, 1535, 1537, 1538, 1539, 1540, and 1541.
-5
777-300ER airplanes, line number: 1530.-6
777-300ER airplanes, line number: 1534.-7
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
5 of 90

### Page 6

DESCRIPTIONCONFIGURATIONGROUP
777-300ER airplanes, line numbers: 1444, 1446, 1448, 1450, 1452,
1470, 1472, 1474, 1476, 1478, 1480, and 1525.
-8
777-300ER airplanes, line number: 1406.-9
777-300ER airplanes, line number: 1398.-10
777F airplanes, line numbers: 1440, 1524, 1526, 1528, 1531, 1532,
and 1536.
-11
777F airplanes, line number: 1520.-12
B. Spares Affected
None.
2. CONCURRENT REQUIREMENTS
None.
3. COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
Requirements Bulletin 777-53A0091 RB. The Airworthiness Directive will make the compliance tasks and
times given in Requirements bulletin 777-53A0091 RB mandatory.
When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When
more than one ACTION is given for a CONDITION or an OPTION, do all of the ACTION numbers for that
CONDITION or OPTION.
Accomplish the required actions, based on the applicable conditions in Tables 1 through 12, in accordance
with the Accomplishment Instructions.
Group 1-2, 5, 7:
Table 1: Station (STA) 655 - Stringers S-20L to S-20R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R
for any crack.
All Airplanes
Export Controlled ECCN: 9E991
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Original Issue: April 08, 2019
777-53A0091 RB
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REQUIREMENTS BULLETIN 777-53A0091
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### Page 7

Group 1-2, 5, 7:
Table 1: Station (STA) 655 - Stringers S-20L to S-20R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 1:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R for any
crack. (a)
CONDITION 2:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
7 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 8

Group 3:
Table 2: Station (STA) 655 - Stringers S-20L to S-4R and S-15R to S-20R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R,
excluding S-5R to S-14R,
for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 3:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R, excluding S-5R to
S-14R, for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5R to S-14R, for
any crack. (a)
CONDITION 4:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
8 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 9

Group 4:
Table 3: Station (STA) 655 - Stringers S-20L to S-6L and S-6R to S-20R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R,
excluding S-5L to S-5R,
for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 5:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 S-20L to S-20R,
excluding S-5L to S-5R,
for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5L to S-5R, for any
crack. (a)
CONDITION 6:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
9 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 10

Group 10:
Table 4: Station (STA) 655 - Stringers S-2L to S-5L Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-2L to S-5L for
any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 7:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-2L to S-
5L for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-2L to S-5L for any
crack. (a)
CONDITION 8:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
10 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 11

Group 11:
Table 5: Station (STA) 655 - Stringers S-13L to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-13L to S-13R
for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 9:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-13L to
S-13R for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-13L to S-13R for any
crack. (a)
CONDITION 10:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
11 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 12

Group 12:
Table 6: Station (STA) 655 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-13L to S-13R,
excluding S-5L to S-5R,
for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 11:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-13L to
S-13R, excluding S-5L to
S-5R, for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-13L to S-13R, exclud-
ing S-5L to S-5R, for any
crack. (a)
CONDITION 12:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
12 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 13

Group 2-3, 5-8:
Table 7: Station (STA) 825+210 - Stringers S-13L to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 12,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
825+210 from S-13L to
S-13R for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 13:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 825+210 from S-13L
to S-13R for any crack.
(a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 825+210
from S-13L to S-13R for
any crack. (a)
CONDITION 14:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
13 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 14

Group 4:
Table 8: Station (STA) 825+210 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 12,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
825+210 from S-13L to
S-13R, excluding S-5L to
S-5R, for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 15:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 825+210 from S-13L
to S-13R, excluding S-5L
to S-5R, for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 825+210
from S-13L to S-13R, ex-
cluding S-5L to S-5R, for
any crack. (a)
CONDITION 16:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
14 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 15

Group 5-6, 9:
Table 9: Station (STA) 1434+189 - Stringers S-13L to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 12,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1434+189 from S-13L to
S-13R for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 17:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1434+189 from S-
13L to S-13R for any
crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1434+189
from S-13L to S-13R for
any crack. (a)
CONDITION 18:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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Group 7:
Table 10: Station (STA) 1434+189 - Stringer S-13L to S-6L and S-6R to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 12,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1434+189 from S-13L to
S-13R, excluding S-5L to
S-5R, for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 19:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1434+189 from S-
13L to S-13R, excluding
S-5L to S-5R, for any
crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1434+189
from S-13L to S-13R, ex-
cluding S-5L to S-5R, for
any crack. (a)
CONDITION 20:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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### Page 17

Group 5-7:
Table 11: Station (STA) 1832 - Stringers S-13L to S-13R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 12,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1832 from S-13L to S-
13R for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 21:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1832 from S-13L to
S-13R for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1832 from
S-13L to S-13R for any
crack. (a)
CONDITION 22:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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### Page 18

Group 6:
Table 12: Station (STA) 655 - Stringers S-20L to S-4R and S-14R to S-20R Inspection
Repeat Interval
(Not to Exceed)
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 42
months after the
Original Issue
date of Require-
ments Bulletin
777-53A0091
RB.
Before 16,000
Total Flight Cy-
cles.
Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R,
excluding S-5R to S-13R,
for any crack.
All Airplanes
-Before further flight.ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 23:
ANY CRACK FOUND.
16,000 flight cy-
cles.
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R, excluding S-5R to
S-13R, for any crack. (a)
16,000 flight cy-
cles.
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5R to S-13R, for
any crack. (a)
CONDITION 24:
NO CRACK FOUND.
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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### Page 19

4. APPROVAL
This Requirements Bulletin was examined by the Federal Aviation Administration (FAA). The changes
specified in this document comply with the applicable regulations and are FAA approved for the airplanes
listed in the service bulletin effectivity. This document and its approval were based on the airplane in its
original Boeing delivery configuration or as modified by other approved Boeing changes.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected by
this Requirements Bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this Requirements Bulletin.
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### Page 20

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BLANK PAGE

### Page 21

5.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
NOTE: 1. This is an Enhanced Required for Compliance document. There w ill be a separate
Service Bulletin (SB) and a separate Requirements Bulletin (RB). If an RB is mandated
by an Airworthiness Directive (AD), then all applicable requirements specified in the
RB must be done. For the related SB, some locations are marked RC Start and RC
End to identify the requirements that are restated from the RB. For the related SB,
the areas between RC Start and RC End, including sub-steps and any figures
identified between RC Start and RC End, must be done to comply with the AD.
Therefore, an Alternative Method of Compliance (AMOC) is required for any deviations
to steps between RC Start and RC End, including substeps and identified figures.
For the related SB, the steps not between RC Start and RC End may be deviated
from using accepted methods in accordance with the operator's maintenance or
inspection program without obtaining approval of an AMOC; this is provided that the
steps between RC Start and RC End, including sub-steps and identified figures, can
still be done as specified, and the airplane can be put back in an airworthy condition.
Figures not required for compliance are omitted from the RB.
2. This is an Enhanced Required for Compliance document. The Boe ing processes
used to create the Service Bulletin (SB) and the Requirements Bulletin (RB) ensure
that the information between "RC Start" and "RC End" in the SB are identical to the
information in the same sections (Compliance, Work Instructions...) of the RB which
the SB refers to as the related document.
3. The compliance times for the actions in WORK INSTRUCTIONS are  in Compliance.
4. Boeing Service Letter 777-SL-51-013, Damage Reporting and Rep air Plan/Design
Guidelines, is an acceptable procedure to request information from Boeing for
additional structural repair instructions. The Service Letter describes what information
must be provided to Boeing before a structural repair can be provided.
5. Unless shown differently, these dimensions and tolerances are  used:
– Linear dimensions are in inches
– Tolerance on linear dimensions, other than rivet and bolt edge  margins, is plus
or minus 0.03 inch
– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch
– Angular tolerance is plus or minus 2 degrees
– Hole dimensions for standard solid rivets and fasteners are in  Structural Repair
Manual (SRM) Chapter 51
– Torque Values:
— Values for structural fasteners are given in 777 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 777
Aircraft Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 777
Aircraft Maintenance Manual (AMM).
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### Page 22

— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
6. These work instructions refer to procedures included in other  Boeing documents.
When the words "refer to" are used and the operator has an accepted alternative
procedure, the accepted alternative procedure can be used. When the words "in
accordance with" are included in the instruction, the procedure in the Boeing document
must be used.
7. Where the work instructions include installation of a kept pa rt, a new or serviceable
part with the same part number can be installed as an alternative to the kept part.
8. If it is necessary to remove more parts for access, you can r emove those parts. If
you can get access without removing identified parts, it is not necessary to remove
all of the identified parts. Jacking and shoring limitations must be observed.
9. Use the approved fastener, process and material substitutions  in accordance with
SRM Chapter 51.
10. A Detailed Inspection is defined as: An intensive examinatio n of a specific item,
installation or assembly to detect damage, failure or irregularity. This could include
tactile assessment in which a component or assembly can be checked for
tightness/security. Available lighting is normally supplemented with a direct source
of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors
and magnifying lenses may be necessary. Surface cleaning and elaborate access
procedures may be required.
11. When more than one OPTION is given for a CONDITION, do only one of the OPTION
numbers. When more than one ACTION is given for a CONDITION or an OPTION,
do all of the ACTION numbers for that CONDITION or OPTION.
12. The instructions in Work Instructions and the figures can in clude operation of tools
or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and
Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain
data on versions of the tools or test equipment that you can use. It is permitted to
use replaced tools. It is not permitted to use superseded tools.
B. WORK INSTRUCTIONS
Actions Required for Compliance
1. Requirements.
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### Page 23

Group 1-2, 5, 7:
Table 1: Station (STA) 655 - Stringers S-20L to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R
for any crack.
All Airplanes
-FIGURE 1
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 1:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R for any crack. (a)
-FIGURE 1
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R for any
crack. (a)
CONDITION 2:
NO CRACK FOUND.
-FIGURE 1
DO PART 2:
CLOSE ACCESS
-
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
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### Page 24

Group 3:
Table 2: Station (STA) 655 - Stringers S-20L to S-4R and S-15R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R
excluding S-5R to S-14R
for any crack.
All Airplanes
-FIGURE 2
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 3:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R, excluding S-5R to
S-14R, for any crack. (a)
-FIGURE 2
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5R, to S-14R for
any crack. (a)
CONDITION 4:
NO CRACK FOUND.
-FIGURE 2
DO PART 2:
CLOSE ACCESS
-
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### Page 25

Group 3:
Table 2: Station (STA) 655 - Stringers S-20L to S-4R and S-15R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
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### Page 26

Group 4:
Table 3: Station (STA) 655 - Stringers S-20L to S-5L and S-5R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R,
excluding S-5L to S-5R,
for any crack.
All Airplanes
-FIGURE 3
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 5:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splice and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R, excluding S-5L to
S-5R, for any crack. (a)
-FIGURE 3
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5L to S-5R, for any
crack. (a)
CONDITION 6:
NO CRACK FOUND.
-FIGURE 3
PART 2: CLOSE
ACCESS
-
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### Page 27

Group 4:
Table 3: Station (STA) 655 - Stringers S-20L to S-5L and S-5R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
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### Page 28

Group 10:
Table 4: Station (STA) 655 - Stringers S-2L to S-5L Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-2L to S-5L for
any crack.
All Airplanes
-FIGURE 4
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 7:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-2L to S-
5L for any crack. (a)
-FIGURE 4
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-2L to S-5L for any
crack. (a)
CONDITION 8:
NO CRACK FOUND.
-FIGURE 4
DO PART 2:
CLOSE ACCESS
-
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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### Page 29

Group 11:
Table 5: Station (STA) 655 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-13L to S-13R
for any crack.
All Airplanes
-FIGURE 5
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 9:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-13L to
S-13R for any crack. (a)
-FIGURE 5
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-13L to S-13R for any
crack. (a)
CONDITION 10:
NO CRACK FOUND.
-FIGURE 5
DO PART 2:
CLOSE ACCESS
-
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
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### Page 30

Group 12:
Table 6: Station (STA) 655 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-13L to S-13R
excluding S-5L to S-5R
for any crack.
All Airplanes
-FIGURE 6
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 11:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-13L to
S-13R, excluding S-5L to
S-5R, for any crack. (a)
-FIGURE 6
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-13L to S-13R, exclud-
ing S-5L to S-5R, for any
crack. (a)
CONDITION 12:
NO CRACK FOUND.
-FIGURE 6
DO PART 2:
CLOSE ACCESS
-
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### Page 31

Group 12:
Table 6: Station (STA) 655 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 32

Group 2-3, 5-8:
Table 7: Station (STA) 825+210 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
825+210 from S-13L to
S-13R for any crack.
All Airplanes
-FIGURE 7
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 13:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 825+210 from S-13L
to S-13R for any crack.
(a)
-FIGURE 7
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 825+210
from S-13L to S-13R for
any crack. (a)
CONDITION 14:
NO CRACK FOUND.
-FIGURE 7
DO PART 2:
CLOSE ACCESS
-
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ALERTALERT

### Page 33

Group 2-3, 5-8:
Table 7: Station (STA) 825+210 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
33 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 34

Group 4:
Table 8: Station (STA) 825+210 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
825+210 from S-13L to
S-13R, excluding S-5L to
S-5R, for any crack.
All Airplanes
-FIGURE 8
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 15:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 825+210 from S-13L
to S-13R, excluding S-5L
to S-5R, for any crack. (a)
-FIGURE 8
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 825+210
from S-13L to S-13R, ex-
cluding S-5L to S-5R, for
any crack. (a)
CONDITION 16:
NO CRACK FOUND.
-FIGURE 8
DO PART 2:
CLOSE ACCESS
-
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ALERTALERT

### Page 35

Group 4:
Table 8: Station (STA) 825+210 - Stringers S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
35 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 36

Group 5-6, 9:
Table 9: Station (STA) 1434+189 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1434+189 from S-13L to
S-13R for any crack.
All Airplanes
-FIGURE 9
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 17:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1434+189 from S-
13L to S-13R for any
crack. (a)
FIGURE 9
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1434+189
from S-13L to S-13R for
any crack. (a)
CONDITION 18:
NO CRACK FOUND.
-FIGURE 9
DO PART 2:
CLOSE ACCESS
-
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ALERTALERT

### Page 37

Group 5-6, 9:
Table 9: Station (STA) 1434+189 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
37 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 38

Group 7:
Table 10: Station (STA) 1434+189 - Stringer S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1434+189 from S-13L to
S-13R excluding S-5L to
S-5R for any crack.
All Airplanes
-FIGURE 10
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 19:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1434+189 from S-
13L to S-13R, excluding
S-5L to S-5R, for any
crack. (a)
-FIGURE 10
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1434+189
from S-13L to S-13R, ex-
cluding S-5L to S-5R, for
any crack. (a)
CONDITION 20:
NO CRACK FOUND.
-FIGURE 10
DO PART 2:
CLOSE ACCESS
-
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ALERTALERT

### Page 39

Group 7:
Table 10: Station (STA) 1434+189 - Stringer S-13L to S-6L and S-6R to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
39 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 40

Group 5-7:
Table 11: Station (STA) 1832 - Stringers S-13L to S-13R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
1832 from S-13L to S-
13R for any crack.
All Airplanes
-FIGURE 11
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 21:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 1832 from S-13L to
S-13R for any crack. (a)
-FIGURE 11
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 1832 from
S-13L to S-13R for any
crack. (a)
CONDITION 22:
NO CRACK FOUND.
-FIGURE 11
DO PART 2:
CLOSE ACCESS
-
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
40 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 41

Group 6:
Table 12: Station (STA) 655 - Stringers S-20L to S-4R and S-14R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
DO PART 1:
OPEN ACCESS
-Do a detailed inspection
of the stringer splices and
skin splice straps, and do
a High Frequency Eddy
Current (HFEC) inspec-
tion of the stringers and
stringer splices at STA
655 from S-20L to S-20R,
excluding S-5R to S-13R,
for any crack.
All Airplanes
-FIGURE 12
DO PART 2:
CLOSE ACCESS
-ACTION 1: Contact The
Boeing Company for re-
pair instructions and do
the repair.
CONDITION 23:
ANY CRACK FOUND.
DO PART 1:
OPEN ACCESS
-ACTION 2: Repeat de-
tailed inspection of the
stringer splices and skin
splice straps, and HFEC
inspection of the stringers
and stringer splices at
STA 655 from S-20L to
S-20R, excluding S-5R to
S-13R, for any crack. (a)
-FIGURE 12
DO PART 2:
CLOSE ACCESS
-
DO PART 1:
OPEN ACCESS
-Repeat detailed inspec-
tion of the stringer splices
and skin splice straps,
and HFEC inspection of
the stringers and stringer
splices at STA 655 from
S-20L to S-20R, exclud-
ing S-5R to S-13R, for
any crack. (a)
CONDITION 24:
NO CRACK FOUND.
-FIGURE 12
DO PART 2:
CLOSE ACCESS
-
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 42

Group 6:
Table 12: Station (STA) 655 - Stringers S-20L to S-4R and S-14R to S-20R Inspection
Refer to the listed
procedures in SB
777-53A0091
Original Issue or
later approved re-
vision as an ac-
cepted procedure
Method of ComplianceActionCondition
(a) It is not required to do repeat inspections in areas where a repair covers the affected inspection zone
provided:
1. The repair is the corrective action to the crack condition identified in this service bulletin and installed
after the original issue date of this service bulletin, AND
2. The installed repair was approved by the Boeing Organizational Designation Authorization via a FAA
Form 8100-9.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 08, 2019
777-53A0091 RB
42 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 43 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT
This Figure applies only to: Group 1-2, 5, 7.
STA
1434
+189
STA
825
+210
STA
655
S-20L
S-OLS.7L S-5L S.3L S-IL/S. /S.1A S.3R  C/L  I S.4RS.5R S.7R
S-9R
S-10L
S-11R
S-12L
S-13L  S-13R
S-14L
S-15R
S-16L
_S-17R
S-18L
. S-19R
S-20L _  Of S-20R
WL 221.14
STA 655
A-A
INSPECTION AREA  2859265
FIGURE 1: STATION (STA) 655 - STRINGERS S-20L TO S-20R INSPECTION
(SHEET 1 OF 4)
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### Page 44 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
> D
(TYPICAL) (4
A + + ++
(TYPICAL) (1  •D
* **
SKIN SPLICE
STRAP
STRINGER
* 9F
-STRINGER
SPLICE
NON-LAP SPLICE AREA
(TYPICAL)
B-B
• STRINGER
(TYPICAL)(4
+ +
(TYPICAL)(  STRINGER
SPLICE
- SKIN SPLICE
STRAP
161  * *
LAP SPLICE AREA
(TYPICAL)  C-C  2859355
HFEC INSPECTION AREA
FIGURE 1: STATION (STA) 655 - STRINGERS S-20L TO S-20R INSPECTION
(SHEET 2 OF 4)
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### Page 45 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
STRINGER
SPLICE
* 0.2
INCH
MINIMUM
SKIN  STRINGER
TYPICAL
D-D
STRINGER
SPLICE
STRINGER  STRINGER
SKIN SPLICE  STRINGER
SKIN  STRAP  CLIP  SKIN
~ HFEC INSPECTION AREA  TYPICAL  E-E  2859501
FIGURE 1: STATION (STA) 655 - STRINGERS S-20L TO S-20R INSPECTION
(SHEET 3 OF 4)
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### Page 46

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for the Station (STA).
More DataQtyIdentificationNameTaskStep
(a)(e)--STRINGER SPLICEInspect1
(b)(e)--SKIN SPLICE STRAPInspect2
(c)(e)--STRINGERInspect3
(d)(e)--STRINGER SPLICEInspect4
(a) Do a detailed inspection of the stringer splice for any crack.
(b) Do a detailed inspection of the skin splice strap, between the stringers, for any crack.
(c) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer, S-20L to S-20R for any crack in accor-
dance with 777 NDT Manual Part 6, 51-00-01. Run the probe along the upstanding web of the stringer
common to the stringer splice.
(d) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer Splice for any crack in accordance with
777 NDT Manual Part 6, 51-00-01. Run the probe on the stringer splice around the fasteners common to
the skin, stringer and stringer splice, and nearest to the skin splice strap.
(e) Removal of the shear ties, stringer clips, skin splice straps, and stringer splices is not required.
FIGURE 1: STATION (STA) 655 - STRINGERS S-20L TO S-20R INSPECTION
(SHEET 4 OF 4)
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 47 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT
This Figure applies only to: Group 3.
1832
STA
1434
+189
STA
825
+210
STA
655
C/L
S-3L S-1L S-1R  S-3R  S-4R
S-5F S-7R
S-9R
S-11R
S-13R
_S-14R
S-15R
_S-17R
.S-19R
S-20L.  1 S-20R
WL 221.14
STA 655
A-A
INSPECTION AREA  2859316
FIGURE 2: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-15R TO S-20R INSPECTION
(SHEET 1 OF 4)
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### Page 48 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
→ D
(TYPICAL) (4
= * **
(TYPICAL)(  > D
* *
• SKIN SPLICE
STRAP
* *+  STRINGER
+ + 91
NON-LAP SPLICE AREA
(TYPICAL)  SPLICE
B-B
(TYPICAL) (4
(TYPICAL)(1  STRINGER
SPLICE
- SKIN SPLICE
STRAP
* *
* **
LAP SPLICE AREA
(TYPICAL)
C-C
2 HFEC INSPECTION AREA  2859492
FIGURE 2: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-15R TO S-20R INSPECTION
(SHEET 2 OF 4)
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### Page 49 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
STRINGER
SPLICE
0.2
INCH
MINIMUM
SKIN  STRINGER
TYPICAL
D-D
STRINGER
SPLICE
STRINGER  STRINGER
SKIN SPLICE  STRINGER
SKIN  STRAP  CLIP  SKIN
HFEC INSPECTION AREA  TYPICAL  E-E  2859533
FIGURE 2: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-15R TO S-20R INSPECTION
(SHEET 3 OF 4)
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Work - See page 1 for details.  49 of 90

### Page 50

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for the Station (STA).
More DataQtyIdentificationNameTaskStep
(a)(e)--STRINGER SPLICEInspect1
(b)(e)--SKIN SPLICE STRAPInspect2
(c)(e)--STRINGERInspect3
(d)(e)--STRINGER SPLICEInspect4
(a) Do a detailed inspection of the stringer splice for any crack.
(b) Do a detailed inspection of the skin splice strap, between the stringers, for any crack.
(c) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer, S-20L to S-4R and S-15R to S-20R
for any crack in accordance with 777 NDT Manual Part 6, 51-00-01. Run the probe along the upstanding
web of the stringer common to the stringer splice.
(d) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer Splice for any crack in accordance with
777 NDT Manual Part 6, 51-00-01. Run the probe on the stringer splice around the fasteners common to
the skin, stringer and stringer splice, and nearest to the skin splice strap.
(e) Removal of the shear ties, stringer clips, skin splice straps, and stringer splices is not required.
FIGURE 2: STATION (STA) 655 - STRINGERS S-20L TO S-4R AND S-15R TO S-20R INSPECTION
(SHEET 4 OF 4)
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 51 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT
This Figure applies only to: Group 4.
1832
STA
1434
+189
STA
825
+210
STA
655
S-20L
S-8L  ,S-7L S-5L S-3L  S:1L|S-1R S-3R S-SR S.7R  C/L
S-9R
S-10L  B
S-11R
S-12L
S-13L  S-13R
S-14L,  C  S-14R
_S-15R
S-16L
_S-17R
S-18L
, S-19R
S-20L _  A S-20R
WL 221.14
STA 655
A-A
INSPECTION AREA  2859319
FIGURE 3: STATION (STA) 655 - STRINGERS S-20L TO S-6L AND S-6R TO S-20R INSPECTION
(SHEET 1 OF 4)
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### Page 52 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
(TYPICAL) 4
* *  E
(TYPICAL)( 1
SKIN SPLICE
STRAP
STRINGER
ÜY
+1911  * .
NON-LAP SPLICE AREA  -STRINGER
(TYPICAL)  SPLICE
B-B
• STRINGER
(TYPICAL)
(TYPICAL)(  STRINGER
SPLICE
• SKIN SPLICE
STRAP
- -*
***
LAP SPLICE AREA
(TYPICAL)
C-C
HFEC INSPECTION AREA  2859493
FIGURE 3: STATION (STA) 655 - STRINGERS S-20L TO S-6L AND S-6R TO S-20R INSPECTION
(SHEET 2 OF 4)
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### Page 53 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
STRINGER
SPLICE
0.2
INCH
MINIMUM
SKIN  STRINGER
TYPICAL
D-D
STRINGER
SPLICE
STRINGER  STRINGER
SKIN SPLICE  STRINGER
SKIN  STRAP  CLIP  SKIN
TYPICAL
E-E
~ HFEC INSPECTION AREA
FIGURE 3: STATION (STA) 655 - STRINGERS S-20L TO S-6L AND S-6R TO S-20R INSPECTION
(SHEET 3 OF 4)
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### Page 54

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for the station (STA).
More DataQtyIdentificationNameTaskStep
(a)(e)--STRINGER SPLICEInspect1
(b)(e)--SKIN SPLICE STRAPInspect2
(c)(e)--STRINGERInspect3
(d)(e)--STRINGER SPLICEInspect4
(a) Do a detailed inspection of the stringer splice for any crack.
(b) Do a detailed inspection of the skin splice strap, between the stringers, for any crack.
(c) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer, S-20L to S-6L and S-6R to S-20R for
any crack in accordance with 777 NDT Manual Part 6, 51-00-01. Run the probe along the upstanding
web of the stringer common to the stringer splice.
(d) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer Splice for any crack in accordance with
777 NDT Manual Part 6, 51-00-01. Run the probe on the stringer splice around the fasteners common to
the skin, stringer and stringer splice, and nearest to the skin splice strap.
(e) Removal of the shear ties, stringer clips, skin splice straps, and stringer splices is not required.
FIGURE 3: STATION (STA) 655 - STRINGERS S-20L TO S-6L AND S-6R TO S-20R INSPECTION
(SHEET 4 OF 4)
Export Controlled ECCN: 9E991
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Original Issue: April 08, 2019
777-53A0091 RB
54 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 55 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT
This Figure applies only to: Group 10.
STA
1434
+189
STA
825
+210
STA
655
S-20L
S-71  S-4LS-3L S-1LS-1R S-3R g-S S-7R  C/L
S-9R
,S-11R
S-13L  S-13R
S-14R
S-15L  S-15R
S-17L,  S-17R
S-19L  _S-19R
WL 221.14
STA 655
A-A
INSPECTION AREA  2859353
FIGURE 4: STATION (STA) 655 - STRINGERS S-2L TO S-5L INSPECTION
(SHEET 1 OF 4)
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### Page 56

FIGURE 4: STATION (STA) 655 - STRINGERS S-2L TO S-5L INSPECTION
(SHEET 2 OF 4)
Export Controlled ECCN: 9E991
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Original Issue: April 08, 2019
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56 of 90
REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 57 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
STRINGER
SPLICE
0.2
INCH
MINIMUM
SKIN  STRINGER
TYPICAL
C-C
STRINGER
SPLICE
STRINGER  STRINGER
SKIN SPLICE  STRINGER
SKIN  STRAP  CLIP  SKIN
~ HFEC INSPECTION AREA  TYPICAL  D-D  2859545
FIGURE 4: STATION (STA) 655 - STRINGERS S-2L TO S-5L INSPECTION
(SHEET 3 OF 4)
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Copyright © Unpublished
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### Page 58

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for the Station (STA).
More DataQtyIdentificationNameTaskStep
(a)(e)--STRINGER SPLICEInspect1
(b)(e)--SKIN SPLICE STRAPInspect2
(c)(e)--STRINGERInspect3
(d)(e)--STRINGER SPLICEInspect4
(a) Do a detailed inspection of the stringer splice for any crack.
(b) Do a detailed inspection of the skin splice strap, between the stringers, for any crack.
(c) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer, S-2L to S-5L for any crack in accordance
with 777 NDT Manual Part 6, 51-00-01. Run the probe along the upstanding web of the stringer common
to the stringer splice.
(d) Do a High Frequency Eddy Current (HFEC) Inspection of Stringer Splice for any crack in accordance with
777 NDT Manual Part 6, 51-00-01. Run the probe on the stringer splice around the fasteners common to
the skin, stringer and stringer splice, and nearest to the skin splice strap.
(e) Removal of the shear ties, stringer clips, skin splice straps, and stringer splices is not required.
FIGURE 4: STATION (STA) 655 - STRINGERS S-2L TO S-5L INSPECTION
(SHEET 4 OF 4)
Export Controlled ECCN: 9E991
Copyright © Unpublished
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Original Issue: April 08, 2019
777-53A0091 RB
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REQUIREMENTS BULLETIN 777-53A0091
ALERTALERT

### Page 59 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
This Figure applies only to: Group 11.
STA
655
S-20L
C/L
S-5L S-3L S-2L  IS-1R S-3R
S01S-71  S-7R
S-10L  S-9R
S-11L  S-11R
S-12L
S-13L  S-13R
_S-14R
S-15R
S-16L
_ S-17R
S-18L
,S-19R
S-20L_  IS20R
WL 221.14
STA 655
A-A
INSPECTION AREA  2859332
FIGURE 5: STATION (STA) 655 - STRINGERS S-13L TO S-13R INSPECTION
(SHEET 1 OF 4)
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### Page 60 (OCR)

REQUIREMENTS BULLETIN 777-53A0091
ALERT  ALERT
> D
(TYPICAL)(
* * **
**  EI
(TYPICAL)( 1.  → D
* *
• SKIN SPLICE
STRAP
STRINGER
_ NON-LAP SPLICE AREA  (TYPICAL)  SPLICE  -STRINGER
B-B
- STRINGER
(TYPICAL) 4
(TYPICAL)(  STRINGER
SPLICE
• SKIN SPLICE
STRAP
LAP SPLICE AREA
(TYPICAL)
HFEC INSPECTION AREA  C-C
2859497
FIGURE 5: STATION (STA) 655 - STRINGERS S-13L TO S-13R INSPECTION
(SHEET 2 OF 4)
Original Issue: April 08, 2019
Export Controlled ECCN: 9E991  777-53A0091 RB
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