AD 85-19-01

85-19-01 BOEING: Amendment 39-5134. Applies to Boeing Model 767 and 757 series airplanes, and certain Model 737 and 727 series airplanes, certificated in any category, equipped with Rosemount Angle of Attack (AOA) sensors identified as Model 861CAB or 861CAK and modification number 0001. To prevent the hazards associated with a malfunctioning AOA sensor caused by loose resolver and/or damper gears, accomplish the following as indicated below, unless already accomplished:

A. Inspect Model 757 and 767 series airplanes equipped with Rosemount AOA sensors, Model 861CAB, modification number 0001, within 300 flight hours or 30 days, whichever is later, after the effective date of this AD, and thereafter at intervals not to exceed 300 flight hours or 30 days, whichever is later, until the replacement prescribed in subparagraph A.1. or A.2., below, is accomplished:

1. Replace Rosemount AOA sensors, serial numbers 00475 through 00629, within 180 days after the effective date ofthis AD, with a unit bearing modification number 0001A, in accordance with the instructions in paragraph C., below.

2. Replace Rosemount AOA sensors, serial numbers 00001 through 00474, within 360 days after the effective date of this AD, with a unit bearing modification number 0001A, in accordance with the instructions in paragraph C., below.

Inspect in accordance with the appropriate Boeing Alert Service Bulletin, 757-34A0026 or 767-34A30, both dated November 12, 1984, or later FAA approved revision. Units determined to be faulty during inspections must be replaced with a serviceable unit, prior to further flight.

B. Inspect Model 727 and 737 series airplanes equipped with Rosemount AOA sensors, Model 861CAK, modification number 0001, within 300 flight hours or 30 days, whichever is later, after the effective date of this AD, and thereafter at intervals not to exceed 300 flight hours or 30 days, whichever is later, until the replacement required in subparagraph B.1., below, is accomplished:

1. Replace Rosemount AOA sensors, serial numbers 00001 through 00173, within 180 days after the effective date of this AD, with a unit bearing modification number 0001A in accordance with the instructions in paragraph C., below.

Inspect in accordance with paragraph 3 of "Accomplishment Instructions" of the appropriate Boeing Alert Service Bulletin, 727-34A0223 or 737-27A1126, both dated November 12, 1984, or later FAA approved revision. Units determined faulty during inspections must be replaced with a serviceable unit, before further flight.

C. Remove, inspect, and rework Rosemount AOA sensors as specified in paragraphs A. and B., above, in accordance with the appropriate Rosemount Service Bulletin, 861CAB-34-02 or 861CAK-34-01, both dated November 12, 1984, or later FAA approved revision. Units found with both resolver gears loose must be returned to Rosemount for rework.

D. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of replacements required by this AD.

All persons affected by this directive who have not already received the above specified service bulletins from the manufacturers may obtain copies upon request to the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124, or Rosemount, Inc., P.O. Box 35129, Minneapolis, Minnesota 55435. They may also be examined at the FAA, Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective October 12, 1985.