79-20-04 LOCKHEED-CALIFORNIA COMPANY: Amendment 39-3576. Applies to all L-1011-385-1, L-1011-385-1-14, and L-1011-385-1-15 series airplanes certificated in all categories.
Compliance required as indicated. To provide a warning to the flight crew of an occurrence of a potentially hazardous jam in the elevator drive system prior to takeoff, and thus prevent takeoff with a possible jammed elevator drive system on the horizontal stabilizer of the primary pitch control system which can result in degradation of the airplane controllability, accomplish the following:
(a) Within the next ten (10) days after the effective date of this AD, unless the elevator drive system jam warning system of paragraph (b) is installed and is operational on all aircraft of each operator's fleet, initiate the following check program:
(1) Prior to each takeoff, conduct an exterior visual check of the elevator/stabilizer surface positions after the full aft controls check and with the control column full forward to assure there is no obvious discrepancy between elevator positions. The pilot-in- command shall be informed of the results of this check.
NOTE: This check can be accomplished with any one single hydraulic system pressurized by any main hydraulic system pump.
(2) If obvious discrepancy is noted, correct prior to further flight.
(3) No further full aft control column movement may be performed prior to takeoff. A placard must be installed in the flight station in full view of the pilot to inform the pilot of the requirements of this subparagraph.
(b) On or before July 1, 1981, unless already accomplished, install the elevator drive system jam warning system in accordance with FAA approved Lockheed-California Company Service Bulletin 093-27-174, dated August 3, 1979. The visual exterior checks of paragraph (a), above, may be discontinued upon installation and operation of the warning system on all aircraft of each operator's L-1011 fleet.
(c) All elevator surface jam conditions indicated by the warning system of paragraph (b) must be corrected prior to further flight.
(d) If the elevator drive system jam warning system is not fully operative prior to initiation of flight operations, the aircraft may be allowed to dispatch provided the visual exterior check of paragraph (a) is accomplished.
(e) Alternative checks, installations or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.
This amendment becomes effective October 11, 1979.