89-14-03 LOCKHEED AERONAUTICAL SYSTEMS COMPANY: Amendment 39-6243.
Applicability: Lockheed Model L-188A and L-188C series airplanes, certificated in any category.
Compliance: Required as indicated, unless previously accomplished.
To prevent airplane control difficulties due to flap asymmetry, accomplish the following:
A. Within 90 days after the effective date of this AD, inspect the flap universal joints to determine if they are splined without a stop.
NOTE: Flap universal joints that are splined without a stop are easily detected by the lack of a screw and washer that holds the pins in place. If they do not have a stop, accomplish the following:
1. Remove from service any flap universal joints that are splined without a stop and install universal joints that are splined with a stop; or
2. Cut a circumferential groove in the splines of the torque tube shafts on each side of the universal joints (1 inch from the end of the shaft) and installa snap ring, in a manner approved by the Manager, Los Angeles Aircraft Certification Office, Northwest Mountain Region. The snap ring is to eliminate the possibility of spline disengagement. The snap ring should completely encircle the shaft; or
3. Modify each universal joint by drilling a hole and installing a 1/8-inch diameter steel pin through each side (two per joint). Locate the pin from .7 to .8-inch from each end, and locate so as to intersect the spline centerline. Peen both pin ends. This modification must be accomplished in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office, Northwest Mountain Region.
NOTE: Local spotfacing may be necessary on pins located at maximum dimension.
B. Within 90 days after the effective date of this AD and thereafter at intervals not to exceed one year, verify proper torque tube-to-universal joint engagement of .375-inch, as specified in Detail E of the L-188 Maintenance Manual, Section 27-6-8, Figure 201; and verify that the distance between the edges of the torque tube shoulders at BL55 is 5.5 to 5.87 inches (universal joints with internal stop), or 6.0 to 6.6 inches for universal joints reworked with added stop pins.
C. Within 90 days after the effective date of this AD and thereafter at intervals not to exceed one year, inspect the wing flap asymmetry shutoff valves, P/N 668225-1, to ascertain whether the valves hang up or respond slowly (greater than 1 second).
1. If the valves hang up or respond slowly, prior to further flight, install a functioning serviceable valve of the same part number (P/N 668225-1) and repeat the inspections at intervals not to exceed one year.
2. Installation of modified valve, P/N 668225-101, or a new valve P/N 668225-101, in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office, Northwest Mountain Region, constitutes terminating action for the repetitive inspections of the wingflap asymmetry shutoff valves required by paragraph C. and C.1., above.
D. Within 90 days after the effective date of this AD, rewire the flap asymmetry annunciator light in the cockpit to trigger the annunciator, in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office, Northwest Mountain Region, so that the light in the cockpit will illuminate when the asymmetry detector is tripped and not be dependent on the shutoff valve.
E. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.
NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.
F. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a base to accomplish the actions required by this AD.
All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Lockheed Aeronautical Systems Company, P.O. Box 551, Burbank, California 91520, Attn: L-188 Commercial Support Contracts, Dept. 63-11, Unit 33. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or 3229 East Spring Street, Long Beach, California.
This amendment (39-6243, AD 89-14-03) becomes effective on July 24, 1989.