# AD 72-11-01: Possible Fire From Fuel Vapor - Type: Airworthiness directive - Status: Current - Products: Piper PA-23-235, PA-23-250 (Navy UO-1) and PA-E23-250 with STC SA179CE or SA867SW - Effective: May 19, 1972 - Published: May 13, 1972 - Issued: May 5, 1972 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-1448 - Registered aircraft: 924 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F52B737F8EE02925862569990050F550.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/72-11-01 ## The airworthiness directive 72-11-01 PIPER AIRCRAFT: Amdt. 39-1448. Applies to PA-23-235, PA-23-250, and PA-E23-250 series airplanes Serial Numbers 27-1 through 27-4765 inclusive, equipped with non-supercharged engines, including airplanes modified in accordance with STC SA179CE and STC SA867SW and certificated in all categories. Compliance required as indicated. In order to prevent possible explosion and fire resulting from fuel vapor ignition during engine starting, accomplish the following: a. Serial Numbers 27-1 through 27-2504 inclusive: Prior to first flight of each day, visually check the lower surface of the wings in the areas of the fuel cells and aft nacelle for fuel stains and any odor of fuel vapor. If fuel stains or any other sign of fuel leakage are observed, the source of leakage must be determined and repairs or replacements accomplished prior to further flight, in accordance with Section IX of Piper Service Manual No. 753464 or an equivalent repair approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. b. Serial Numbers 27-2505 through 27-4765 inclusive: Inspect in accordance with paragraph (a) above within 50 hours' time in service after the effective date of this AD or since the last inspection and every 50 hours thereafter. c. The checks required by paragraphs (a) and (b) above may be performed by the pilot, including pilots of aircraft engaged in Air Carrier operations. A chronological listing of compliance with this AD must be made in the airplane's permanent maintenance log in accordance with FAR 91.173. d. When the instruction paragraph contained in Piper Service Letter No. 606 is complied with or equivalent inspections and alterations approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, further compliance with this AD is not required. (Piper Service Letters Nos. 449 and 449A refer to this subject.) This AD supersedes AD 70-03-08. This amendment is effective May19, 1972. ## 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 3 of 6 models: PA-23-235, PA-E23-250, PA-23-250 (Navy UO-1) ## 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: 924 (924 by airframe model, 0 by engine model) - Makers: Piper 924 Models with the most aircraft: - [Piper PA-23-250](https://openairdocs.org/model/piper-pa-23-250): 894 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 3 models: https://openairdocs.org/ad/72-11-01/models.md Every aircraft: https://openairdocs.org/ad/72-11-01/aircraft.md ## Related documents - [STC SA179CE](https://openairdocs.org/stc/SA179CE): Installation of the following: Engines: Lycoming IO-540-A1A5 or Lycoming IO-540-G1A5; Propellers: Hartzell HC-A3XK-2C/8433-10 or HC A3XK-2B/7636D-4; Data required: Doyn approved Drawing List 2200.. D'Shannon Products Ltd., Named in the applicability - [STC SA867SW](https://openairdocs.org/stc/SA867SW): Lycoming O-540-A1D5 engines.. Airline Fueling Inc., Named in the applicability ## 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, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB SEA85LA018](https://openairdocs.org/ntsb/SEA85LA018), Nov 16, 1984: Piper PA-23-250 (N5276Y), Aurora, OR, substantial damage --- 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.