# AD 81-24-09: Propeller Performance

- Type: Airworthiness directive
- Status: Current
- Products: Lockheed Martin 188A and 188C
- Effective: December 28, 1981
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-4267
- Registered aircraft: 4 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/ED08DDFA7BCF7A0886256975004938D6.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/81-24-09

## The airworthiness directive

81-24-09 LOCKHEED-CALIFORNIA COMPANY: Amendment 39-4267. Applies to Lockheed Model 188A and 188C Series airplanes, certificated in all categories.

Compliance required within 30 days after the effective date of this AD, unless already accomplished.

To prevent a reduction in performance which could result in a hazardous condition, incorporate in the Limitations Section of the FAA-Approved Airplane Flight Manual a revision which specifies that all takeoffs and approaches must be performed with the synchronization control in the following position:

For Hamilton Standard Propellers -

SYNC MASTER switch-OFF

For Aeroproducts Propellers -

Synchronizer switch-SYNCH OFF.

This amendment becomes effective December 28, 1981.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4A22](https://openairdocs.org/tcds/4A22): Lockheed Martin Corporation; names 2 of 2 models: 188A, 188C

## 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 (4 by airframe model, 0 by engine model)
- Makers: Lockheed 4

Models with the most aircraft:

- [Lockheed 188C](https://openairdocs.org/model/lockheed-188c): 3 aircraft (airframe model)
- [Lockheed 188A](https://openairdocs.org/model/lockheed-188a): 1 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/81-24-09/models.md
Every aircraft: https://openairdocs.org/ad/81-24-09/aircraft.md

Its text cites no advisory circulars or STCs.

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