# AD 78-23-08: Fuel Pump To Fuel Injector Tube Elbow

- Type: Airworthiness directive
- Status: Current
- Products: Lycoming Engines IO-540-G1B5, IO-540-K1F5, IO-540-P1A5 and IO-540-S1A5
- Effective: November 7, 1978
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-3334
- Registered aircraft: 4,238 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9852E32769A646BF8625682C007720CA.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/78-23-08

## The airworthiness directive

78-23-08 AVCO LYCOMING: Amendment 39-3334. Applies to all IO-540-G1B5, -K1F5, -P1A5 and - S1A5 series engines with serial numbers up to and including L-17835-48 or -45A and all IO-540-G1B5, -K1F5, - P1A5, -S1A5 series engines overhauled (also known as remanufactured) by Lycoming prior to March 30, 1978. Compliance required within the next 50 hours' in service after the effective date of this AD, unless already accomplished. To prevent possible fuel leakage due to failure of the fuel pump to fuel injector tube elbow replace the fuel pump to fuel injector tube part number LW-10445 and the fuel pump to fuel injector tube elbow, part number LW-10446 with flexible hose assembly, part number LW-12877-6-051. Upon submission of substantiating data through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration (FAA), Eastern Region, may adjust the compliance time specified in this AD. (NOTE: AVCO Lycoming Service Bulletin No. 421 covers this subject.) This amendment is effective November 7, 1978.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1E4](https://openairdocs.org/tcds/1E4): Lycoming Engines; names 4 of 81 models: IO-540-G1B5, IO-540-P1A5, IO-540-S1A5, IO-540-K1F5

## 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: 4,238 (0 by airframe model, 4,238 by engine model)
- Makers: Piper 1,480, Cessna 1,109, Robinson Helicopter 294, Maule 229, Socata 156, Rockwell International 85, Commander 63, Smith 41, Aerofab 26, Bellanca 25

Models with the most aircraft:

- [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series): 4,219 aircraft (engine model)
- [Lycoming IO-540-S1A5](https://openairdocs.org/engine/lycoming-io-540-s1a5): 10 aircraft (engine model)
- [Lycoming IO-540-P1A5](https://openairdocs.org/engine/lycoming-io-540-p1a5): 4 aircraft (engine model)
- [Lycoming IO-540-G1B5](https://openairdocs.org/engine/lycoming-io-540-g1b5): 3 aircraft (engine model)
- [Lycoming IO-540-K1F5](https://openairdocs.org/engine/lycoming-io-540-k1f5): 2 aircraft (engine model)

All 6 models: https://openairdocs.org/ad/78-23-08/models.md
Every aircraft: https://openairdocs.org/ad/78-23-08/aircraft.md

Its text cites no advisory circulars or STCs.

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