48-49-03: Electrical Circuit Inspection
FAA order 48-49-03 is an airworthiness directive. The FAA's subject line: Electrical Circuit Inspection. System: electrical power.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- The Boeing Company
- Models
- DC-6, DC-6A, DC-6B
Dates and paperwork
- Docket
- Unknown
- Status
- Current
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (1,309 characters)
48-49-03 DOUGLAS: Applies to All DC-6 Airplanes. \n\n\tCompliance required not later than March 1, 1949. \n\n\tTo 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). \n\n\tIn an undetermined number of aircraft some of the essential circuits were inadvertently connected to the distribution bus rather than to the master bus. \n\n\tIt 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: \n\n\tRadio 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. \n\n\t(Douglas Service Letter A214-T.3338/TFW dated October 22, 1948 covers this same subject.)
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/48-49-03.json · aircraft systems.