# AD 86-22-05: Flap Sector Mounting Brackets Inspection - Type: Airworthiness directive - Status: Current - Products: Learjet 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25 and 14 more - Effective: November 10, 1986 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small/large airplane - Amendment: 39-5448 - Registered aircraft: 353 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F7B871CDB1A3C94F8625698800760963.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/86-22-05 ## The airworthiness directive 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. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A10CE](https://openairdocs.org/tcds/A10CE): Learjet Inc.; names 25 of 29 models: 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E… - [TCDS A5CE](https://openairdocs.org/tcds/A5CE): Learjet Inc.; names 1 of 1 models: 23 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 353 (353 by airframe model, 0 by engine model) - Makers: Gates Learjet 219, Gates Lear Jet 80, Learjet 54 Models with the most aircraft: - [Gates Learjet 35A](https://openairdocs.org/model/gates-learjet-35a): 135 aircraft (airframe model) - [Gates Learjet 55](https://openairdocs.org/model/gates-learjet-55): 54 aircraft (airframe model) - [Learjet 35A](https://openairdocs.org/model/learjet-35a): 24 aircraft (airframe model) - [Gates Lear Jet 36A](https://openairdocs.org/model/gates-lear-jet-36a): 21 aircraft (airframe model) - [Gates Learjet 25D](https://openairdocs.org/model/gates-learjet-25d): 20 aircraft (airframe model) - [Gates Lear Jet 35](https://openairdocs.org/model/gates-lear-jet-35): 16 aircraft (airframe model) - [Gates Lear Jet 36](https://openairdocs.org/model/gates-lear-jet-36): 13 aircraft (airframe model) - [Gates Lear Jet 25B](https://openairdocs.org/model/gates-lear-jet-25b): 12 aircraft (airframe model) - [Learjet 24](https://openairdocs.org/model/learjet-24): 7 aircraft (airframe model) - [Gates Lear Jet 24D](https://openairdocs.org/model/gates-lear-jet-24d): 7 aircraft (airframe model) - [Learjet 23](https://openairdocs.org/model/learjet-23): 6 aircraft (airframe model) - [Gates Learjet 55C](https://openairdocs.org/model/gates-learjet-55c): 6 aircraft (airframe model) - [Learjet 24D](https://openairdocs.org/model/learjet-24d): 4 aircraft (airframe model) - [Gates Lear Jet 24F](https://openairdocs.org/model/gates-lear-jet-24f): 4 aircraft (airframe model) - [Learjet 55](https://openairdocs.org/model/learjet-55): 4 aircraft (airframe model) - [Learjet 24B](https://openairdocs.org/model/learjet-24b): 3 aircraft (airframe model) - [Gates Lear Jet 28](https://openairdocs.org/model/gates-lear-jet-28): 3 aircraft (airframe model) - [Gates Learjet 55B](https://openairdocs.org/model/gates-learjet-55b): 3 aircraft (airframe model) - [Learjet 24A](https://openairdocs.org/model/learjet-24a): 2 aircraft (airframe model) - [Gates Lear Jet 24E](https://openairdocs.org/model/gates-lear-jet-24e): 2 aircraft (airframe model) All 27 models: https://openairdocs.org/ad/86-22-05/models.md Every aircraft: https://openairdocs.org/ad/86-22-05/aircraft.md Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ATL86FA203](https://openairdocs.org/ntsb/ATL86FA203), Jul 21, 1986: Bell 222UT (N222DU), Chapel Hill, NC, substantial damage --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.