# AD 54-04-01: Spark Plugs

- Type: Airworthiness directive
- Status: Current
- Products: AC Spark Plug LA-87 Spark Plugs
- Superseded by: Nothing supersedes this AD
- Product type: Appliance
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0350EF3DB774D72F86256A3000703E05.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/54-04-01

## The airworthiness directive

54-04-01 AC SPARK PLUG: Applies to All Engines Equipped With AC LA-87 Spark Plugs, Except Pratt and Whitney R-1830 Engines of 1,200 HP or Less and Wright R-1820 Engines of 1,200 HP or Less.

Compliance required prior to March 1, 1954.

A. In order to preclude possibilities of engine failure, when using AC LS-87 spark plugs in engines for which they are not approved, these spark plugs must be removed from all engines with the exceptions of the R-1820 having a T.O. rating of 1,200 h.p. or less and the R-1830 having a T.O. rating of 1,200 h.p. or less.

B. On R-1820 and R-1830 engines of 1,200 h.p. or less, the LS-87 plug is limited to a maximum of 120 hours of service with no reconditioning permitted. Plugs having over 120 hours must be removed from service.

This supersedes AD 49-26-02.

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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