# AD 68-13-03: Fuel Cell Collapse - Type: Airworthiness directive - Status: Current - Products: Piper PA-24 and PA-24-250 - Published: February 28, 1969 - Issued: February 18, 1969 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-727 - Registered aircraft: 1,567 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BB49C4F1E801F2CB86256E0100546BF6.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/68-13-03 ## The airworthiness directive 68-13-03 PIPER: Amdt. 39-727. Applies to Piper Models PA-24 and PA-24-250 aircraft S/N 24-1 through 24-3529 inclusive. Compliance required as indicated below until Piper fuel cell vent and drain tube modification kits are installed (Kit No. 760277 for main tanks and Kit No. 760281 for auxiliary tanks if installed) in accordance with Piper Service Letter No. 516 or a later approved revision or an equivalent modification approved by the Chief, Engineering and Manufacturing Branch, Eastern Region. To prevent fuel exhaustion caused by fuel cell collapse and loss of fuel through the tank filler caps accomplish the following: 1. Within 25 hours' time in service after the effective date of this AD and every 100 hours' time in service thereafter perform the following inspections: (a) Visually inspect the main fuel cells and the auxiliary fuel cells if installed for indications of fuel cell collapse. Inspect the upper and lower fasteners of the main fuel cells and theupper fasteners of the auxiliary fuel cells which retain the bladder cells to assure security in accordance with Section VIII of Piper Comanche Service Manual No. 753516 or an equivalent inspection approved by the Chief, Engineering and Manufacturing Branch, Eastern Region. The fuel cells shall be empty when performing this inspection. Also, with the tank filler caps removed, inspect the tank vent tubes under the wing for dirt or ice blockage. Apply suction to each vent tube outlet to assure that there is no blockage. (b) Inspect all fuel cell filler caps for secureness and assure installation of proper part number cap. If the rubber portion of the "thermos" type filler caps (S/N 24-581 and up) shows indications of dryness or hardness which can cause the cap to gradually loosen, the cap must be replaced. (c) Accomplish a fuel quantity gauge sending unit check in accordance with Section VIII of Piper Comanche Service Manual No. 753516 or an equivalent inspection approved by the Chief, Engineering and Manufacturing Branch, Eastern Region. 2. Within 100 hours' time in service after the effective date of this AD, unless already accomplished on aircraft S/N 24-581 through 24-3495 inclusive, alter the fuel cell drain tubes in accordance with Piper Service Bulletin No. 216 dated June 21, 1963, or an equivalent alteration approved by the Chief, Engineering and Manufacturing Branch, Eastern Region. (Piper Service Bulletins Nos. 216 and 231A and Service Letter No. 367 and 516 pertain to this subject.) Effective May 29, 1968. Revised March 5, 1969. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 1A15](https://openairdocs.org/tcds/1A15): Piper Aircraft Inc.; names 2 of 4 models: PA-24, PA-24-250 ## 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: 1,567 (1,567 by airframe model, 0 by engine model) - Makers: Piper 1,567 Models with the most aircraft: - [Piper PA-24-250](https://openairdocs.org/model/piper-pa-24-250): 1,222 aircraft (airframe model) - [Piper PA-24](https://openairdocs.org/model/piper-pa-24): 345 aircraft (airframe model) All 2 models: https://openairdocs.org/ad/68-13-03/models.md Every aircraft: https://openairdocs.org/ad/68-13-03/aircraft.md Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (3) 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 FTW02LA173](https://openairdocs.org/ntsb/FTW02LA173), Jun 8, 2002: Piper PA-24-250 (N146P), Provo, UT, substantial damage. Probable cause: the total loss of engine power for reasons undetermined. - [NTSB ATL89LA044](https://openairdocs.org/ntsb/ATL89LA044), Nov 23, 1988: Piper PA-24-250 (N6711P), Ft Mill, SC, substantial damage - [NTSB MIA87LA104](https://openairdocs.org/ntsb/MIA87LA104), Mar 11, 1987: Piper PA-24-250 (N7645P), Navarre, FL, 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.