# AD 85-08-05: Strut Housing Inspection - Type: Airworthiness directive - Status: Current - Products: Piper PA-31, PA-31-300, PA-31-325, PA-31-350, PA-31P, PA-31T, PA-31T1, PA-31T2 and PA-31T3 - Effective: May 15, 1985 - Published: May 30, 1985 - Issued: May 15, 1985 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-5040 - Registered aircraft: 782 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2D01CBC876E4E580862569A6005C9C04.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/85-08-05 ## The airworthiness directive 85-08-05 PIPER: Amendment 39-5040. Applies to Models PA-31/PA-31-300 and PA-31-325 (S/Ns 31-2 through 31-8312014); PA-31-350 (S/Ns 31-5001 through 31-8352042); PA-31-350 T-1020 (S/Ns 31-8153001 through 31-8353007); PA-31P (S/Ns 31P-1 through 31P-7730012); PA-31T (S/Ns 31T-7400002 through 31T-8120104); PA-31T1 (S/Ns 31T-7804001 through 31T-8304003 and 31T-1104004 through 31T-1104006; PA-31T2 (S/Ns 31T-8166001 through 31T-8166071, 31T-8166073, and 31T-8166076) and PA-31T3 T-1040 (S/Ns 31T-8275001 through 31T-8375003) airplanes certificated in any category. Compliance: Required within the next 100 hours time-in-service after the effective date of this AD, unless already accomplished. To preclude loss of the main and nose landing gear, accomplish the following: (a) On all applicable airplanes, remove each piston tube assembly from its strut housing in accordance with instructions in the appropriate Maintenance Manual. (1) Inspect the interior walls of each struthousing for abnormal wear or damage (gouges, scoring, ridges, non-concentric wear). Replace housing assembly if such wear or damage is indicated. (2) Remove and replace the retaining pins connecting the upper bearing to the piston tube in accordance with either paragraph (a)(4)(i) or (a)(4)(ii) of this AD. The bearing and piston tube are drilled to allow slip fit, and the pins should come out easily. Seizing or deformation of pins is an indication of the damage described in paragraph (a)(4)(i), below. (3) On Models PA-31/PA-31-300 and PA-31-325 (S/Ns 31-2 through 31-8312014); PA-31-350 (S/Ns 31-5001 through 31-8352042); PA-31P (S/Ns 31P-1 through 31P-7730012); PA-31T (S/Ns 31T-7400002 through 31T-8020088); PA-31T1 (S/Ns 31T-7804001 through 31T-8004055); PA-31T2 (S/Ns 31T-8166001 through 31T-8166013) airplanes only: Remove the upper bearing and inspect the area shown in Sketch A of Piper Service Bulletin No. 779A dated July 16, 1984. If ridges are found in the designated inspection area, replace the bearing. Inspect replacement bearings in accordance with Sketch A prior to installation. (4) Visually inspect the pin holes in the piston tube. (i) If holes are found to be elongated, deformed, chamferred, or out of tolerance (holes should be concentric with nominal dimension of .250 - .251), or if standard Piper Part Number 01821-06 or 01821-07 pins cannot be pressed easily into holes, install oversize pins in accordance with either Piper Kit 764 417 or Piper Kit 764 418. (ii) If holes are acceptable, replace pins with new harder retaining pins, Piper Part Number 01821-06 or Piper Part Number 01821-07, as applicable for the strut involved. (5) Reassemble the strut, replacing all seals, rings and wipers with new parts per applicable parts catalog and reinstall landing gear in accordance with appropriate Maintenance Manual. (b) Aircraft may be flown in accordance with FAR 21.197 to a location where this AD can be accomplished. (c) An equivalent method of compliance with this AD may be used if approved by the Manager, Atlanta Aircraft Certification Office, ACE-115A, FAA Central Region, 1075 Inner Loop Road, College Park, Georgia 30337; telephone (404) 763-7428. This amendment becomes effective on May 20, 1985. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A8EA](https://openairdocs.org/tcds/A8EA): Piper Aircraft Inc.; names 5 of 6 models: PA-31T2, PA-31T, PA-31T1, PA-31P, PA-31T3 - [TCDS A20SO](https://openairdocs.org/tcds/A20SO): Piper Aircraft Inc.; names 4 of 4 models: PA-31, PA-31-325, PA-31-300, PA-31-350 ## 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: 782 (782 by airframe model, 0 by engine model) - Makers: Piper 782 Models with the most aircraft: - [Piper PA-31-350](https://openairdocs.org/model/piper-pa-31-350): 399 aircraft (airframe model) - [Piper PA-31-325](https://openairdocs.org/model/piper-pa-31-325): 137 aircraft (airframe model) - [Piper PA-31T](https://openairdocs.org/model/piper-pa-31t): 87 aircraft (airframe model) - [Piper PA-31T1](https://openairdocs.org/model/piper-pa-31t1): 64 aircraft (airframe model) - [Piper PA-31P](https://openairdocs.org/model/piper-pa-31p): 40 aircraft (airframe model) - [Piper PA-31](https://openairdocs.org/model/piper-pa-31): 26 aircraft (airframe model) - [Piper PA-31T2](https://openairdocs.org/model/piper-pa-31t2): 24 aircraft (airframe model) - [Piper PA-31-300](https://openairdocs.org/model/piper-pa-31-300): 3 aircraft (airframe model) - [Piper PA-31T3](https://openairdocs.org/model/piper-pa-31t3): 2 aircraft (airframe model) All 9 models: https://openairdocs.org/ad/85-08-05/models.md Every aircraft: https://openairdocs.org/ad/85-08-05/aircraft.md Its text cites no advisory circulars or STCs. --- 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.