# AD 78-21-03: Fuel Lines - Type: Airworthiness directive - Status: Current - Products: Piper PA-34-200T - Effective: October 26, 1978 - Published: May 25, 1978 - Issued: May 17, 1978 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-3316 - Registered aircraft: 563 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/CA42970E3A6176CA8625699E004ADFA3.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/78-21-03 ## The airworthiness directive 78-21-03 PIPER AIRCRAFT CORPORATION: Amendment 39-3316. Applies to Model PA-34-200T, serial numbers 34-7570001 through 34-7870207, certificated in all categories. Compliance is required within the next ten hours' time in service after the effective date of this A.D. unless already accomplished. To prevent a fuel leak, accomplish the following: (a) On serial numbers 34-7570001 through 34-7870194, accomplish the following: (1) Remove the right and left engine nacelle aft hatch assemblies. (2) In the right engine aft nacelle compartment, inspect the fuel inlet line to the boost pump at the mixture control cable for evidence of chafing. (i) If chafing is evident, replace the fuel line with the approved fuel line, Piper Part Number 95153-145. Install protective sleeves, Piper Part Numbers 63882-73 and 63882-83, or equivalent fuel resistant flexible sleeves on the fuel inlet line and the mixture control cable. Secure the sleeves in place with tie raps, Piper Part Number 488-702 or equivalent fuel resistant devices (see Figure No. 1). Leak check the fuel line using normal maintenance procedures. (ii) If no chafing is evident, remove existing clamps or Koroseal tie (if installed) and install protective sleeves, Piper Part Number 63882-73 and 63882-83, or equivalent fuel resistant flexible sleeves on the fuel inlet line and the mixture control cable. Secure the sleeves in place with tie raps, Piper Part Number 488-702, or equivalent fuel resistant devices (see Figure No. 1). (3) In the left engine aft nacelle compartment, inspect the fuel inlet line to the boost pump at the propeller governor control cable for evidence of chafing. (i) If chafing is evident, replace the fuel line with the approved fuel line, Piper Part Number 95153-144. Secure the fuel line to the control cable as shown in Figure No. 2. Leak check the fuel line using normal maintenance procedures. (ii) If no chafing is evident, unless already accomplished, secure the fuel line to the control cable as shown in Figure No. 2. (4) Replace the right and left engine nacelle aft hatch assemblies and make appropriate maintenance record entry. (b) On serial numbers 34-7870195 through 34-7870207, accomplish the following: (1) Remove the right engine nacelle aft hatch assembly. (2) Inspect the fuel inlet line to the boost pump at the mixture control cable for evidence of chafing. (i) If chafing is evident, replace the fuel line with the approved fuel line, Piper Part Number 95153-145. Install protective sleeves, Piper Part Number 63882-73 and 63882-83, or equivalent fuel resistant flexible sleeves on the fuel inlet line and the mixture control cable. Secure the sleeves in place with tie raps, Piper Part Number 488-702 or equivalent fuel resistant devices (see Figure No. 1). Leak check the fuel line using normal maintenance procedures. (ii) If no chafing is evident, remove existing clamps or Koroseal tie (if installed) and install protective sleeves, Piper Part Number 63882-73 and 63882-83, or equivalent fuel resistant flexible sleeves on the fuel inlet line and the mixture control cable. Secure the sleeves in place with tie raps, Piper Part Number 488-702, or equivalent fuel resistant devices, (see Figure No. 1). (3) Replace the right nacelle aft hatch assembly and make appropriate maintenance record entry. (c) An alternate method of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. (Piper Service Bulletin 596A, dated September 11, 1978, pertains to this same subject.) This supersedes Amendment 39-3222, 43 FR 22341, AD 78-11-04. This amendment becomes effective October 26, 1978. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A7SO](https://openairdocs.org/tcds/A7SO): Piper Aircraft Inc.; names 1 of 5 models: PA-34-200T (Seneca II) ## 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: 563 (563 by airframe model, 0 by engine model) - Makers: Piper 563 Models with the most aircraft: - [Piper PA-34-200T](https://openairdocs.org/model/piper-pa-34-200t): 563 aircraft (airframe model) All 1 models: https://openairdocs.org/ad/78-21-03/models.md Every aircraft: https://openairdocs.org/ad/78-21-03/aircraft.md Its text cites no advisory circulars or STCs. --- 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.