# AD 71-21-04: Piston Bearing Lock Pins

- Type: Airworthiness directive
- Status: Current
- Products: Kelowna Flightcraft R & D 340, 440 and Military C-131E
- Effective: October 28, 1971
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-1308
- Registered aircraft: 12 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/56297F57C1D0629E862569B20075715A.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/71-21-04

## The airworthiness directive

71-21-04 GENERAL DYNAMICS: Amdt. 39-1308. Applies to Models 340, 440 and C- 131E Airplanes including those using turbopropeller power.

Compliance required as indicated.

To prevent failure of lockpins retaining the piston upper bearing and possible subsequent loss of the piston assembly from the main landing gear, accomplish the following:

  (a) Within the next 300 hours' time in service from the effective date of this AD, unless already accomplished within the last 1200 hours' time in service, and at intervals not to exceed 1500 hours' time in service thereafter, inspect the piston upper bearing retaining lockpins on those main landing gears known to have a single lockpin configuration or unknown lockpin configuration.

1. If loose or damaged lockpin(s) are discovered, replace lockpins before further flight.

2. Aircraft may be flown per FAR 21.197 to a base for rework.

  (b) Within 1000 hours' time in service from the effective date of this AD, unless already accomplished within the last 2000 hours' time in service, and thereafter at intervals not to exceed 3000 hours' time in service, inspect the piston upper bearing retaining lockpins on those main landing gears known to have more than a single lockpin configuration.

1. If loose or damaged lockpin(s) are discovered, replace lockpins before further flight.

2. Aircraft may be flown per FAR 21.197 to a base for rework.

  (c) The repetitive inspection intervals in (a) and (b) may be extended to 8000 hours when rework has been accomplished per Paragraph 2B, General Dynamics/Convair Service Bulletin No. 32-5, dated 3 September 1971, or later FAA approved revision, or a rework approved by the Chief, Aircraft Engineering Division, FAA Western Region.

  (d) Upon request of the operator, an FAA Air Carrier Maintenance Inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region, may adjust the repetitive inspection intervals specified inthis AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator.

This amendment becomes effective October 28, 1971.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 6A6](https://openairdocs.org/tcds/6A6): Kelowna Flightcraft R & D Ltd.; names 3 of 6 models: 340, Military C-131E, 440

## 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: 12 (12 by airframe model, 0 by engine model)
- Makers: Convair 12

Models with the most aircraft:

- [Convair 340](https://openairdocs.org/model/convair-340): 7 aircraft (airframe model)
- [Convair 440](https://openairdocs.org/model/convair-440): 5 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/71-21-04/models.md
Every aircraft: https://openairdocs.org/ad/71-21-04/aircraft.md

Its text cites no advisory circulars or STCs.

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