# AD 52-04-07: Heater Control Modification

- Type: Airworthiness directive
- Status: Current
- Products: Martin-Marietta 202 and 202A
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/88DA625B931F27C086256A3200584F9B.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/52-04-07

## The airworthiness directive

52-04-07 MARTIN: Applies to All Models 202 and 202A Aircraft Except as Noted.

Compliance required not later than July 1, 1952.

The following controls and their wiring are common to two wing anti-icing heaters. The controls listed are identical in each nacelle. Modify the system so each of the controls serves only one heater:

1. Emergency high heat 400 degrees cutout switch.

2. Firewall shutoff switch.

3. Fuel pump circuit breaker (supplies power to ignition controls and master fuel controls).

4. Fuel shutoff relay.

5. Wiring to the master and auxiliary solenoid valves.

6. Fuel booster pump relay (has dual power input but single ground on the control circuit).

7. Ignition relay (202 only).

8. Ignition transformer (202 only).

9. Ignition circuit breaker (202 only).

10. AC safety relay (202 only).

(Trans World Airlines Engineering Order 5838 covers this same subject for the 202A).

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A-795](https://openairdocs.org/tcds/A-795): Martin-Marietta Corporation; names 2 of 2 models: 202A, 202

## 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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