# AD 88-21-07 R1: Fuel Filler Compartment

- Type: Airworthiness directive
- Status: Current
- Products: Piper PA-23, PA-23-160, PA-23-235, PA-23-250, PA-23-250 (Navy UO-1) and PA-E23-250
- Effective: August 22, 1989
- Published: July 24, 1989
- Issued: July 11, 1989
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Small airplane
- Amendment: 39-6272
- Registered aircraft: 1,267 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/07E686ABC519A030862569A6005CA32C.0001
- DRS record last changed: November 21, 2025
- Page: https://openairdocs.org/ad/88-21-07-R1

## The airworthiness directive

88-21-07 R1 PIPER: Amendment 39-6042 as revised by Amendment 39-6272.

Applicability: Model PA-23, PA-23-160, PA-23-250, PA-23-235 and PA-E23-250 (all serial numbers) airplanes certificated in any category, except Model PA-23-250 airplanes, serial numbers 27-7654001 through 27-8154030.

Compliance: Required within the next 60 calendar days after the effective date of this AD and at intervals not to exceed 12 calendar months thereafter, unless already accomplished per the unrevised version of this AD.

To reduce the possibility of precipitation and/or wash water from entering the fuel filler compartment and leaking into the fuel cell resulting in engine failure, accomplish the following:

  (a) Inspect the fuel vent/drain lines, the thermos type fuel cell caps, and the fuel filler compartment covers on both main fuel cell systems and, if installed, both auxiliary fuel cell systems in accordance with the instructions in Piper Service Bulletin (SB) No. 340, dated May 24, 1971.

  (b) If any defects are found, correct them before further flight.

  (c) Airplanes may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished.

  (d) An equivalent means of compliance with this AD may be used if approved by the Manager, Atlanta Aircraft Certification Office, ACE-115A, Federal Aviation Administration, 1669 Phoenix Parkway, Suite 210C, Atlanta, Georgia 30349.

This AD revises AD 88-21-07, Amendment 39-6042, which became effective on November 6, 1988.

This amendment (39-6272, AD 88-21-07 R1) becomes effective on August 22, 1989.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1A10](https://openairdocs.org/tcds/1A10): Piper Aircraft Inc.; names 5 of 6 models: PA-23-160, PA-23-235, PA-E23-250, PA-23-250 (Navy UO-1), PA-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: 1,267 (1,267 by airframe model, 0 by engine model)
- Makers: Piper 1,267

Models with the most aircraft:

- [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250): 894 aircraft (airframe model)
- [Piper PA-23-160](https://openairdocs.org/model/piper-pa-23-160): 188 aircraft (airframe model)
- [Piper PA-23](https://openairdocs.org/model/piper-pa-23): 155 aircraft (airframe model)
- [Piper PA-23-235](https://openairdocs.org/model/piper-pa-23-235): 25 aircraft (airframe model)
- [Piper PA-23-250 (6PCLM)](https://openairdocs.org/model/piper-pa-23-250-6pclm): 5 aircraft (airframe model)

All 5 models: https://openairdocs.org/ad/88-21-07-R1/models.md
Every aircraft: https://openairdocs.org/ad/88-21-07-R1/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; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB ATL94LA136](https://openairdocs.org/ntsb/ATL94LA136), Jul 11, 1994: Piper PA-23-160 (N3381P), Hampton, GA, substantial damage. Probable cause: THE PILOT'S INADEQUATE AIRCRAFT PRE-FLIGHT INSPECTION, HIS FAILURE TO ABORT THE TAKEOFF, AND HIS FAILURE TO MAINTAIN AIRSPEED THAT RESULTED IN A STALL. A FACTOR WAS THE INADEQUATE AIRCRAFT INSPECTION…

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