# AD 48-11-01: Ungrounding Modification - Class B - Type: Airworthiness directive - Status: Current - Products: Boeing DC-6, DC-6A and DC-6B - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Registered aircraft: 17 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/5A28CDCD6C314F20862569BC0056658A.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/48-11-01 ## The airworthiness directive 48-11-01 DOUGLAS: Applies to DC-6 Aircraft. To be accomplished prior to return to service in class B operation-with cabin heating and thermal deicing, including windshield, operative, but with cabin supercharging inoperative. Rework must be accomplished in accordance with the following Douglas Co. data: 1. Accomplish all rework covered by data listed in Note 48-10-01 for class A operation with the exception of the rework outlined in Service Bulletins No. 258, No. 225 and No. 230. Also accomplish paragraphs 1 and 2 but do not accomplish 3 of Note 48-10-01. 2. Rework in accordance with the following must also be accomplished: Service Bulletin DC-6 No. 223, Stainless Steel Heater Discharge Ducts and Windshield Anti-Icing Ducts, as revised February 24, 1948. Service Bulletin DC-6 No. 38, Heater Fire Warning Switch-Installation of, dated October 6, 1947. Service Bulletin DC-6 No. 250, Cabin Heater Shut-Off Control, dated February 19, 1948. Service Bulletin DC-6 No. 211, Main Cabin Heater Exhaust-Revision of, as revised February 23, 1948. Service Bulletin DC-6 No. 227, Cabin Heater Scoop Segregation, as revised February 24, 1948. Service Bulletin DC-6 No. 243, Revise Cabin Heater Ignition Conduit in Boiler Room and Hell-Hole Area, as revised January 26, 1948. Service Bulletin DC-6 No. 245, Heater and Buffet Power Cable Conduit, as revised February 24, 1948. The rework outlined in the data listed above is based upon an airplane which incorporates certain production changes. Therefore, in order to satisfactorily complete the rework required, some aircraft* must also be revised in accordance with the following: Service Bulletin DC-6 No. 40, Heater Exhaust Fire Detector-Replacement of, dated September 3, 1947. (Accomplish partially*). Service Bulletin DC-6 No. 71, Installation-Oil Trap and Drain, Cabin Heater Combustion Air Duct, dated September 3, 1947. (Accomplish Electrical Phase of Service Bulletin only.) Service Bulletin DC-6 No. 96, Windshield De-icing Air Discharge Revision, dated December 22, 1947. Service Bulletin DC-6 No. 141, Improvements in DC-6 Cabin Pressure and Cabin Air Conditioning Systems, dated February 19, 1948. Service Bulletin DC-6 No. 150, Revision-Cockpit and Windshield Heat Control System and Windshield Air Exhaust, dated December 11, 1947. Service Bulletin DC-6 No. 160, Cabin Air Mixing Valve Actuator, dated February 2, 1948. Service Bulletin DC-6 No. 179, Ground Blower Electrical Wiring Revision, dated December 29, 1947. Service Bulletin DC-6 No. 28, Installation of Ammeter and Selector Switch for Functional Check of Pitot and Air Scoop Anti-Icing Heaters, dated August 20, 1947. (Must be accomplished completely except that P/N 3320167-516 nameplate, 1 required, shall be deleted.) In addition to the above, the following must also be accomplished in all aircraft: (a) Disconnect the superchargers and drain and flushsupercharger oil system. *Serial numbers of airplanes affected by this rework are listed on the pertinent Service Bulletin(s). Also, additional information may be obtained from the "Supplement" to "Cross Reference List-Service Changes and Modification Items" which has been prepared and revised by the Douglas Co. as of February 11, 1948. ## Affected data sheets (3) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 6A3](https://openairdocs.org/tcds/6A3): The Boeing Company; names 1 of 3 models: DC-6A - [TCDS 6A4](https://openairdocs.org/tcds/6A4): The Boeing Company; names 1 of 2 models: DC-6B - [TCDS A-781](https://openairdocs.org/tcds/A-781): The Boeing Company; names 1 of 1 models: DC-6 ## 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: 17 (17 by airframe model, 0 by engine model) - Makers: Douglas 17 Models with the most aircraft: - [Douglas DC-6B](https://openairdocs.org/model/douglas-dc-6b): 9 aircraft (airframe model) - [Douglas DC-6A](https://openairdocs.org/model/douglas-dc-6a): 7 aircraft (airframe model) - [Douglas DC-6](https://openairdocs.org/model/douglas-dc-6): 1 aircraft (airframe model) All 3 models: https://openairdocs.org/ad/48-11-01/models.md Every aircraft: https://openairdocs.org/ad/48-11-01/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.