AD 86-22-05

86-22-05 GATES LEARJET: Amendment 39-5448. Applies to the following Gates Learjet series airplanes, models/serial number listed below, certificated in any category.

MODEL SERIAL NUMBER 23 003 thru 089 (if equipped with dual flap actuators) 23 090 thru 099 24 100 thru 357 25 003 thru 373 28 001 thru 005 29 001 thru 004 35 002 thru 545, 589 thru 598 36 001 thru 053, and 055 55 001 thru 121

Compliance required as indicated, unless previously accomplished.

To prevent impairment of flap operation, an asymmetric flap condition, false gear warning horn signals, or incorrect biasing of the stall warning system, due to flap sector upper mount bracket failures, accomplish the following:

A. Within the next 50 hours time-in-service after the effective date of this AD, inspect the flap sector upper mounting brackets for cracks, in accordance with instructions in Gates Learjet Corporation Airplane Modification Kit (AMK) 86-4 or 55-86-2, as applicable.

1. If cracks are found in either the left-hand or right-hand flap sector upper mounting brackets (Figure I of AMK), prior to further flight, replace both brackets and install stiffeners in accordance with the applicable AMK.

2. If cracks are not found in the flap sector upper mounting brackets, replace the brackets and install stiffeners in accordance with the applicable AMK within 100 hours time-in-service after the effective date of this AD.

B. If both flap sector upper mounting brackets have been previously replaced with steel brackets, compliance with this AD is not required.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

D. Alternate means of compliance with this AD, which provides an acceptable level of safety, may be used when approved by the Manager, Wichita Aircraft Certification Office, FAA, Central Region.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Gates Learjet Corporation, P.O. Box 7707, Wichita, Kansas 67277. These documents may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, Central Region, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, Kansas.

This supersedes AD 84-20-06, Amendment 39-4908.

This amendment becomes effective November 10, 1986.