# AD 55-20-02: Wing Skin Heat Shields

- Type: Airworthiness directive
- Status: Current
- Products: Boeing DC-7, DC-7B and DC-7C
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 5 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D88D8F50EC76B2EE862569BC006578DA.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/55-20-02

## The airworthiness directive

55-20-02 DOUGLAS: Applies to All Douglas DC-7 Aircraft Serial Numbers 44122 to 44146 Inclusive, 44171 to 44174 Inclusive, 44261 to 44289 Inclusive and 44679 to 44684 Inclusive.

Compliance required as soon as possible but not later than February 1, 1956.

Revising the injection pump timing on the engines creates higher exhaust gas temperatures across the top surface of the wing along the left-hand side of the outboard nacelle. In order to reduce the wing skin temperature, an additional heat shield must be installed between the center and rear spars, and replace the aft section of the existing heat shields between the front and center spars adjacent to the upper left side of the outboard nacelle in the exhaust path area.

(Douglas Service Bulletin DC-7 No. 77 dated July 1, 1955, covers this same subject.)

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 4A10](https://openairdocs.org/tcds/4A10): The Boeing Company; names 3 of 3 models: DC-7, DC-7C, DC-7B

## 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: 5 (5 by airframe model, 0 by engine model)
- Makers: Douglas 5

Models with the most aircraft:

- [Douglas DC-7](https://openairdocs.org/model/douglas-dc-7): 2 aircraft (airframe model)
- [Douglas DC-7B](https://openairdocs.org/model/douglas-dc-7b): 2 aircraft (airframe model)
- [Douglas DC-7C](https://openairdocs.org/model/douglas-dc-7c): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/55-20-02/models.md
Every aircraft: https://openairdocs.org/ad/55-20-02/aircraft.md

Its text cites no advisory circulars or STCs.

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