# AD 74-20-01: Main Landing Gear Trunnion

- Type: Airworthiness directive
- Status: Current
- Products: Cessna 310Q, 340, 402B, 414 and 421B
- Effective: September 25, 1974
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-1966
- Registered aircraft: 957 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C9DAB378942A3C5086256A34006494E4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/74-20-01

## The airworthiness directive

74-20-01 CESSNA: Amendment 39-1966. Applies to Models 310Q (Serial Numbers 1038 through 1069, 1071 through 1081, 1083 through 1086, 1088 through 1105, 1107, 1109, 1110, 1112, 1113, 1115 through 1118, 1122, 1123, 1125 and 1126); Model 340 (Serial Numbers 0325 through 0354); Model 402B (Serial Numbers 0575 through 0581, 0583 through 0586, 0588, 0590 through 0611, 0613, 0614 and 0617); Model 414 (Serial Numbers 0503 through 0529, 0531 and 0532); and Model 421B (Serial Numbers 0322, 0584 through 0625, 0627, 0629 through 0633, 0635 and 0636) airplanes.

Compliance: Required as indicated, unless already accomplished.

To preclude possible main landing gear trunnion failure, accomplish the following:

A) Within 25 hours' time in service after the effective date of this AD, visually inspect the LH and RH main landing gear assembly to determine whether the landing gear assembly serial numbers fall within the following serial number blocks:

Aircraft Models Affected

Main Landing Gear Assembly Serials Affected

L/H R/H Model 310Q B170 thru B279 W146 thru W273 Model 340 B199 thru B345 B164 thru B330 Model 402B B199 thru B345 B164 thru B330 Model 414 B199 thru B345 B164 thru B330 Model 421B W108 thru W185 W090 thru W170

If a main landing gear assembly falls within the above serial number blocks, visually inspect the trunnions for cracks or forming flaws in accordance with Cessna Service Letter ME74-14 dated August 9, 1974, or subsequent revisions. Repeat these inspections at intervals of 25 hours' time in service thereafter until the trunnions are replaced.

B) If cracks or forming flaws are found during any inspection required by Paragraph A, prior to further flight, replace the main landing gear upper strut with an airworthy part in accordance with Cessna Service Kit 421-63.

C) Within 100 hours' time in service after the effective date of this AD, replace main landing gear upper strut assemblies of the serial numbers listed in Paragraph A with an airworthy part in accordance with Cessna Service Kit 421-63.

D) The inspections required by this AD may be discontinued upon replacement of the affected main landing gear upper strut assemblies.

E) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

This amendment becomes effective September 25, 1974.

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A7CE](https://openairdocs.org/tcds/A7CE): Textron Aviation Inc.; names 3 of 16 models: 402B, 414, 421B
- [TCDS 3A10](https://openairdocs.org/tcds/3A10): Textron Aviation Inc.; names 1 of 23 models: 310Q
- [TCDS 3A25](https://openairdocs.org/tcds/3A25): Textron Aviation Inc.; names 1 of 11 models: 340

## 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: 957 (957 by airframe model, 0 by engine model)
- Makers: Cessna 957

Models with the most aircraft:

- [Cessna 310Q](https://openairdocs.org/model/cessna-310q): 277 aircraft (airframe model)
- [Cessna 414](https://openairdocs.org/model/cessna-414): 242 aircraft (airframe model)
- [Cessna 421B](https://openairdocs.org/model/cessna-421b): 225 aircraft (airframe model)
- [Cessna 340](https://openairdocs.org/model/cessna-340): 164 aircraft (airframe model)
- [Cessna 402B](https://openairdocs.org/model/cessna-402b): 49 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/74-20-01/models.md
Every aircraft: https://openairdocs.org/ad/74-20-01/aircraft.md

Its text cites no advisory circulars or STCs.

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