- Models
- DC-6, DC-6A, DC-6B
- Registered aircraft
- 17 matched by model
- Product
- Aircraft · Large airplane
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
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On this page
The airworthiness directive
48-49-03 DOUGLAS: Applies to All DC-6 Airplanes.
Compliance required not later than March 1, 1949.
To reduce the probability of a loss of power for electrical circuits considered to be essential in flight, these essential circuits were designed to be connected directly to the master bus. Other less essential circuits are connected to the master bus through a 500-ampere Burndy limiter (fuse).
In an undetermined number of aircraft some of the essential circuits were inadvertently connected to the distribution bus rather than to the master bus.
It is necessary, therefore, that all DC-6 aircraft be inspected and such rewiring as necessary be done to assure that the following circuit protectors are connected to the master bus:
Radio Master (B1-102), Fuel Booster Pumps (B1-63, 97), Invertor Power (B1-111, 116), Propeller Booster (Curtiss Propellers only, F1-28, 29), Propeller Control (Curtiss: B1-141, 142, 143, 144. Hamilton Standard: B1-188, 189, 190, 191), Propeller Synchronizer (B1-145), Governor Control (Hamilton Standard only, B1-192), Generator Control Panel (Eclipse Generator System only, B1-246, 247, 248, 249. Reference Douglas Service Bulletin DC-6 No. 329.
(Douglas Service Letter A214-T.3338/TFW dated October 22, 1948 covers this same subject.)
Affected TCDS · 3
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 17
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1953 | 1 |
|---|---|
| 1954 | 2 |
| 1956 | 1 |
| 1957 | 3 |
| 1958 | 3 |
| 1959 | 1 |
6 with no year recorded