National Transportation Safety Board Report 223
As a result of this accident, the National Transportation Safety
Board has recommended that the Federal Aviation Administration:
* Issue immediately an emergency airworthiness directive to inspect all pylon attach points on all DC-10 aircraft by approved inspection methods. (Class I, Urgent Action) (A-79-41)
* Issue a telegraphic airworthiness directive to require an immediate inspection of all DC-10 aircraft in which an engine pylon assembly has been removed and reinstalled for damage to the wing-mounted pylon aft bulkhead, including its forward flange and the attaching spar web and fasteners. Require removal of any sealant which may hide a crack in the flange area and employ eddy-current or other approved techniques to ensure detection of such damage. (Class I, Urgent Action) (A-79-45)
* Issue a maintenance alert bulletin directing FAA maintenance inspectors to contact their assigned carriers and advise them to immediately discontinue the practice of lowering and raising the pylon with the engine still attached. Carriers should adhere to the procedure recommended by the Douglas Aircraft Company service
bulletin which include removing the engine from the pylon before
removing the pylon from the wing. (Class I, Urgent Action) (A-79-46)
* Issue a maintenance alert bulletin to U.S. certificated air carriers,
and notify States that have regulatory responsibilities over for-
eign air carriers operating DC-10 aircraft, to require appropriate
structural inspections of the engine pylons following engine fail-
r ures involving significant imbalance conditions or severe side
d loads. (Class I, Urgent Action) (A-79-52)
e * Incorporate in type certification procedures consideration of-
(a) Factors which affect maintainability, such as accessibility for inspection, positive or redundant retention of connecting hardware and the clearances of interconnecting parts in the design of critical structural elements; and
(b) Possible failure combinations which can result from primary structural damage in areas through which essential systems are routed. (Class II, @ority Action) (A-79-98)
in * Insure that the design of transport category aircraft provides positive protection against asymmetry of lift devices during critical phases of flight; or, if certification is based upon demonstrated
Of controllability of the aircraf t under condition of asymmetry, insure that asymmetric warning systems, stall warning systems, or other