# AD 77-08-02: Electrical Short

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-31, PA-31-300, PA-31-325, PA-31-350, PA-31P and PA-31T
- Effective: November 15, 1977
- Published: April 18, 1977
- Issued: April 6, 1977
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-3074
- Registered aircraft: 692 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/61EBFBEC3C1DD2A586256E1200499288.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/77-08-02

## The airworthiness directive

77-08-02 PIPER: Amendment 39-2874 as amended by Amendment 39-3074. Applies to PA-31, PA-31-300 and PA-31-325, S/Nos. 31-752 thru 31-7712010; PA-31-350, S/Nos. 31-5001 thru 31-7752028; PA-31P, S/Nos. 31P-67 thru 31P-7730001; PA-31T, S/Nos. 31T-7400002 thru 31T-7720008.

Compliance required within the next 50 hours in service after the effective date of this AD unless already accomplished.

To avoid an electrical short between the Pilot/Copilot Microphone and Phone Jack Relay and mounting bracket, comply as follows:

  (a) Key both the pilot and copilot microphone at the same time. If you can transmit through the pilot's microphone, the subject relay is not installed in the aircraft and no further action is required.

  (b) If the relay is installed, comply with the "Instructions" paragraph of Piper Service Bulletin No. 526A, dated July 25, 1977, or with an approved equivalent method.

Upon request with substantiating data submitted through an FAA Maintenance Inspector, the compliance time specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, who must also approve equivalent methods of compliance.

Amendment 39-2874 become effective April 20, 1977.

This amendment 39-3074 is effective November 15, 1977.

## Affected data sheets (2) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [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
- [TCDS A8EA](https://openairdocs.org/tcds/A8EA): Piper Aircraft Inc.; names 2 of 6 models: PA-31T, PA-31P

## 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: 692 (692 by airframe model, 0 by engine model)
- Makers: Piper 692

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-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-31-300](https://openairdocs.org/model/piper-pa-31-300): 3 aircraft (airframe model)

All 6 models: https://openairdocs.org/ad/77-08-02/models.md
Every aircraft: https://openairdocs.org/ad/77-08-02/aircraft.md

Its text cites no advisory circulars or STCs.

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