LAX07LA064

NTSB accident investigation · Boeing 737-7H4 · San Diego, CA · December 27, 2006

Accident · No injuriesLimited investigationFinal report
Date
December 26, 2006, 18:12 local (Dec 27, 2006, 02:12 UTC)
Place
San Diego, CA
Injuries
208 uninjured
Phase of flight
Taxi
Aircraft
N207WNBoeing 737-7H4N673AABoeing 737-3A4
Weather
Visual (VMC) · Night
Status
Completed · report June 30, 2008
Report
Approved by Office Director
Parties
Southwest Airlines, Federal Aviation Administration San Diego FSDO
FAA report
20061226029532A
Case key
65084

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

Failure of the captain of the other taxiing airplane to maintain clearance from an occupied airplane stopped on the ramp.

Failure of the captain, during taxi, to maintain adequate clearance from an occupied airplane stopped on the ramp.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Collision between aircraft (other than midair)Taxi - to takeoff
Wing,winglet - separation
Clearance - not maintainedPilot in commandCause
Collision between aircraft (other than midair)Taxi - pushback/tow
Horizontal stabilizer - penetrated
Clearance - not maintainedPilot of other aircraftCause

Analysis

Flight 1092 was parked at gate 5. The crew received pushback clearance, and was advised of a company airplane taxiing from gate 1. Ground personnel pushed flight 1092 back, and the captain set the airplane's brakes. The crew of flight 1011 received clearance to taxi from gate 1 to runway 27, and was advised to use caution because of a company airplane pushing back from gate 5. The crew of the taxiing airplane performed taxi checklist items, and discussed using caution regarding the stopped airplane that had been pushed back from gate 5. The first officer (FO) of the taxiing airplane pointed out that there was an open area on his side of the airplane in case the captain needed to deviate to the right for clearance. Flight data recorder information indicated that the taxiing airplane turned to the right (away from the stationary airplane) about 26.5 degrees while moving at a maximum ground speed of 11 knots. It then turned about 2.5 degrees back to the left (towards the stationary airplane) while the brakes were applied, and it stopped. About 8 seconds after coming to a stop, it began moving forward. It collided with the other airplane about 2 seconds later at a recorded groundspeed of 3 knots. The crew of the taxiing airplane was not sure what they hit. The left winglet from the taxiing airplane struck the right horizontal stabilizer of the stopped airplane. The top half of the winglet sheared off, and imbedded itself in the horizontal stabilizer just outboard of the elevator.

Flight 1092 was parked at gate 5. The crew received pushback clearance, and was advised of a company airplane taxiing from gate 1. Ground personnel pushed flight 1092 back, and the captain set the airplane's brakes. The crew of flight 1011 received clearance to taxi from gate 1 to runway 27, and was advised to use caution because of a company airplane pushing back from gate 5. The crew of the taxiing airplane performed taxi checklist items, and discussed using caution regarding the stopped airplane that had been pushed back from gate 5. The first officer (FO) of the taxiing airplane pointed out that there was an open area on his side of the airplane in case the captain needed to deviate to the right for clearance. Flight data recorder information indicated that the taxiing airplane turned to the right (away from the stationary airplane) about 26.5 degrees while moving at a maximum ground speed of 11 knots. It then turned about 2.5 degrees back to the left (towards the stationary airplane) while the brakes were applied, and it stopped. About 8 seconds after coming to a stop, it began moving forward. It collided with the other airplane about 2 seconds later at a recorded groundspeed of 3 knots. The crew of the taxiing airplane was not sure what they hit. The left winglet from the taxiing airplane struck the right horizontal stabilizer of the stopped airplane. The top half of the winglet sheared off, and imbedded itself in the horizontal stabilizer just outboard of the elevator.

Factual narrative

On December 26, 2006, about 1812 Pacific standard time, while taxiing to the runway, Southwest Airlines flight 1011, a Boeing 737-7H4, N207WN, collided on the ground with Southwest Airlines flight 1092, a Boeing 737-3A4, N673AA, that had been pushed back from its gate at San Diego International Airport, San Diego, California. Southwest Airlines Company was operating both airplanes as scheduled domestic passenger flights under the provisions of 14 Code of Federal Regulations (CFR) Part 121. The airline transport pilot licensed captain, first officer, 3 flight attendants, and 72 passengers on flight 1011 were not injured. The airplane received minor damage. The airline transport pilot licensed captain, first officer, 3 flight attendants, and 126 passengers on flight 1092 were not injured. The airplane was substantially damaged. Flight 1011 was departing as a non-stop to Las Vegas, Nevada, and flight 1092 was departing as a non-stop to San Jose, California. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed for both airplanes.

Flight Data Recorders (FDR)

An engineer in the Safety Board's Vehicle Recorder Division received electronic files containing FDR data from both airplanes. The engineer correlated data from each FDR to their Greenwich Mean Time (GMT) data, and then calculated the relationships for each set of FDR data. This data was used to change the elapsed FDR subframe reference number data to FDR GMT. However, the engineer pointed out that GMT data comes from each airplane's captain's clock, and those times could be slightly different, which would affect the established time base.

The plotted data indicated that the taxiing airplane turned to the right (away from the stationary airplane) about 26.5 degrees while moving at a maximum ground speed of 11 knots. It then turned about 2.5 degrees back to the left (towards the stationary airplane) while the brakes were applied, and it stopped. About 8 seconds after coming to a stop, it began moving forward. It collided with the other airplane about 2 seconds later at a recorded groundspeed of 3 knots.

Cockpit Voice Recorders (CVR)

A Safety Board specialist reviewed the cockpit voice recorders from both airplanes and prepared a summary of selected events that occurred during the event.

Flight 1092 was at gate 5. The crew received pushback clearance, and was advised of a company airplane taxing from gate 1 at 1810:06. After pushback, the ground crewman asked the captain to set the brakes. The captain responded that the brakes were set at 1811:39. About 21 seconds later, there were sounds of the impact, and the captain made an exclamation. The first officer and ground crewman exclaimed that another airplane had made contact with them. Thirteen seconds after the impact, the first officer broadcast the word stop four times over the radio.

Flight 1011 was at gate 1, and requested pushback clearance from ground control at 1807:50. The captain had the airplane pushed back, started engines, and advised that the brakes were set at 1809:14. About 52 seconds later, the CVR picked up a radio transmission from ground control that cleared the airplane at gate 5 for pushback. There was no acknowledgement from the flight 1011 crew to indicate that they heard this transmission. The crew commenced setting flaps and performing taxi checklist items. Ground control cleared the airplane to taxi to runway 27, and told them at 1810:46 to use caution because of the company airplane pushing back from gate 5. The first officer (FO) acknowledged the transmission. The captain indicated that they should use caution regarding that airplane; the FO reiterated the caution and clearance to runway 27.

During taxi, the FO indicated that so far they were doing good, and that there was plenty of room on his side if the captain needed to swing it his way a little. The captain indicated that if he swung the airplane it would move the wing. A few seconds later, the FO asked if they had made contact. The CVR recorded the four stop transmissions from the other flight crew, but there was no indication that the crew heard them. The captain asked what they hit, and the FO responded that he didn't know, but it was on the captain's side.

The left winglet from the taxiing airplane, flight 1011, struck the right horizontal stabilizer of the stopped airplane, flight 1092. The top half of the winglet sheared off, and imbedded itself in the horizontal stabilizer just outboard of the elevator.

On December 26, 2006, about 1812 Pacific standard time, while taxiing to the runway, Southwest Airlines flight 1011, a Boeing 737-7H4, N207WN, collided on the ground with Southwest Airlines flight 1092, a Boeing 737-3A4, N673AA, that had been pushed back from its gate at San Diego International Airport, San Diego, California. Southwest Airlines Company was operating both airplanes as scheduled domestic passenger flights under the provisions of 14 Code of Federal Regulations (CFR) Part 121. The airline transport pilot licensed captain, first officer, 3 flight attendants, and 72 passengers on flight 1011 were not injured. The airplane received minor damage. The airline transport pilot licensed captain, first officer, 3 flight attendants, and 126 passengers on flight 1092 were not injured. The airplane was substantially damaged. Flight 1011 was departing as a non-stop to Las Vegas, Nevada, and flight 1092 was departing as a non-stop to San Jose, California. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed for both airplanes.

Flight Data Recorders (FDR)

An engineer in the Safety Board's Vehicle Recorder Division received electronic files containing FDR data from both airplanes. The engineer correlated data from each FDR to their Greenwich Mean Time (GMT) data, and then calculated the relationships for each set of FDR data. This data was used to change the elapsed FDR subframe reference number data to FDR GMT. However, the engineer pointed out that GMT data comes from each airplane's captain's clock, and those times could be slightly different, which would affect the established time base.

The plotted data indicated that the taxiing airplane turned to the right (away from the stationary airplane) about 26.5 degrees while moving at a maximum ground speed of 11 knots. It then turned about 2.5 degrees back to the left (towards the stationary airplane) while the brakes were applied, and it stopped. About 8 seconds after coming to a stop, it began moving forward. It collided with the other airplane about 2 seconds later at a recorded groundspeed of 3 knots.

Cockpit Voice Recorders (CVR)

A Safety Board specialist reviewed the cockpit voice recorders from both airplanes and prepared a summary of selected events that occurred during the event.

Flight 1092 was at gate 5. The crew received pushback clearance, and was advised of a company airplane taxing from gate 1 at 1810:06. After pushback, the ground crewman asked the captain to set the brakes. The captain responded that the brakes were set at 1811:39. About 21 seconds later, there were sounds of the impact, and the captain made an exclamation. The first officer and ground crewman exclaimed that another airplane had made contact with them. Thirteen seconds after the impact, the first officer broadcast the word stop four times over the radio.

Flight 1011 was at gate 1, and requested pushback clearance from ground control at 1807:50. The captain had the airplane pushed back, started engines, and advised that the brakes were set at 1809:14. About 52 seconds later, the CVR picked up a radio transmission from ground control that cleared the airplane at gate 5 for pushback. There was no acknowledgement from the flight 1011 crew to indicate that they heard this transmission. The crew commenced setting flaps and performing taxi checklist items. Ground control cleared the airplane to taxi to runway 27, and told them at 1810:46 to use caution because of the company airplane pushing back from gate 5. The first officer (FO) acknowledged the transmission. The captain indicated that they should use caution regarding that airplane; the FO reiterated the caution and clearance to runway 27.

During taxi, the FO indicated that so far they were doing good, and that there was plenty of room on his side if the captain needed to swing it his way a little. The captain indicated that if he swung the airplane it would move the wing. A few seconds later, the FO asked if they had made contact. The CVR recorded the four stop transmissions from the other flight crew, but there was no indication that the crew heard them. The captain asked what they hit, and the FO responded that he didn't know, but it was on the captain's side.

The left winglet from the taxiing airplane, flight 1011, struck the right horizontal stabilizer of the stopped airplane, flight 1092. The top half of the winglet sheared off, and imbedded itself in the horizontal stabilizer just outboard of the elevator.

Aircraft · 2

Registration
N207WN
Reported as
Boeing 737-7H4
Category
Airplane
Serial number
34012
Engines
CFM International CFM-56, turbo fanCFM International CFM-56, turbo fan
Damage
Minor damage
Flight
Part 121
Registered owner
Southwest Airlines Co
Airworthiness certificate
Standard, Transport
Departed
SAN · San Diego, CA
Destination
LAS · Las Vegas, NV
Flight plan
IFR
Airport
KSAN · San Diego

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Registration
N673AA
Reported as
Boeing 737-3A4
Category
Airplane
Serial number
23251
Engines
CFM International CFM-56, turbo fanCFM International CFM-56, turbo fan
Damage
Substantial damage
Flight
Part 121
Registered owner
Southwest Airlines Co
Airworthiness certificate
Standard, Transport
Departed
SAN · San Diego, CA
Destination
SJC · San Jose, CA
Flight plan
IFR
Airport
KSAN · San Diego

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 4

As NTSB recorded them. NTSB leaves out names.

Role
Pilot, aircraft N207WN
Age
56
Injuries
None
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1
Last flight review
January 1, 2006
Seat
Left
Flight hours
27,000 total · 23,500 in this make and model · 23,500 as pilot in command · 190 in the last 90 days · 85 in the last 30 days · 4 in the last 24 hours
Role
Co-pilot, aircraft N207WN
Age
47
Injuries
None
Certificates
Private, Commercial, Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1
Last flight review
April 1, 2006
Seat
Right
Flight hours
7,945 total · 4,866 in this make and model · 2,614 as pilot in command · 252 in the last 90 days · 80 in the last 30 days · 3 in the last 24 hours
Role
Pilot, aircraft N673AA
Age
48
Injuries
None
Certificates
Airline transport, Commercial
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1
Last flight review
July 1, 2006
Seat
Left
Flight hours
9,000 total · 6,500 in this make and model · 5,000 as pilot in command · 210 in the last 90 days · 85 in the last 30 days · 7 in the last 24 hours
Role
Co-pilot, aircraft N673AA
Age
35
Injuries
None
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1
Last flight review
March 1, 2006
Seat
Rear
Flight hours
8,102 total · 1,335 in this make and model · 4,707 as pilot in command · 206 in the last 90 days · 83 in the last 30 days · 7 in the last 24 hours

Weather

Conditions
Visual (VMC) · Night
Wind
0° at 0 knots
Visibility
10 statute miles
Lowest ceiling
20,000 ft broken
Temperature
61 °F, dew point 46 °F
Altimeter
30.03 inHg
Observed at
SAN

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.