87-04-06 GATES LEARJET CORPORATION: Amendment 39-5530. Applies to Learjet Models 35, 35A, 36, and 36A airplanes equipped with a J.E.T. FC-530 autopilot/flight director; Model 35A airplanes equipped with a J.E.T. FC-535 autopilot/flight director; and Model 55 airplanes equipped with a J.E.T. FC-550 autopilot/flight director; certificated in any category.
Compliance required as indicated, unless already accomplished.
To prevent the potential for operations with unsafe flight director steering commands, accomplish the following:
A. For Models 35, 35A, 36, and 36A airplanes equipped with J.E.T. FC-530 autopilot/flight director, except airplanes S/N 35-620, 35-627 and subsequent, and 36-057 and subsequent, within the next 10 hours time-in-service after the effective date of this AD, insert the following information in "Section I - Limitations" of the Gates Learjet 35/36 series Airplane Flight Manual Supplement (AFMS) for the J.E.T. FC-530 autopilot/flight director, AFMS W1029, dated 4/23/85, revised 3/11/86 (or Gates Learjet 35A, 36A J.E.T. FC-530 autopilot/flight director, AFMS W1029, dated 9/20/82, revised 5/13/83):
1. Add the following limitation and Note:
Flight director VOR enroute and approach operations are prohibited.
NOTE: Autopilot-coupled VOR operations and raw data displays are not affected and may be used.
2. Change the final limitation to read as follows:
For autopilot V0R approach, the flaps must be lowered to 8 degrees or more.
B. For Model 35A airplanes equipped with J.E.T. FC-535 autopilot/flight directors within the next 10 hours time-in-service after the effective date of this AD, insert the following information in "Section I - Limitations" of the Gates Learjet Model 35A/36A AFMS for the J.E.T. FC-535 autopilot/flight director, AFMS T1204, dated 3/16/84, revised 4/4/84:
1. Add the following limitation and Note:
Flight director VOR/TACAN enroute and approach operations are prohibited.NOTE: Autopilot-coupled V0R/TACAN operations and raw data displays are not affected and may be used.
2. Change the final limitation to read as follows:
For autopilot V0R/TACAN approach, the flaps must be lowered to 8 degrees or more.
C. For Model 55 airplanes equipped with J.E.T. FC-550 autopilot/flight directors, airplanes Serial Numbers 55-003 through 55-011, not incorporating ECR 2524, ECR 2525, AAK 55-81-2, or AAK 55-83-1, within the next 10 hours time-in-service after the effective date of this AD, insert the following information in "Section I - Limitations" of the Gates Learjet Model 55 AFMS for the J.E.T. FC-550 autopilot/flight director, AFMS W1001, dated 4/14/81, revised 8/31/81:
1. Add the following limitation and Note:
Flight director VOR enroute operations are prohibited.
NOTE: Autopilot-coupled VOR enroute operations and raw data displays are not affected and may be used.
D. For Model 55 airplanes equipped with J.E.T. FC-550 autopilot/flight director.- airplanes S/N 55-003 through 55-011, incorporating ECR 2524, ECR 2525, AAK 55-81-2, or AAK 55-83-I; and airplanes S/N 55-012 through 55-126; within the next 10 hours time-in-service after the effective date of this AD, insert the following information in "Section I - Limitations" of the appropriate Gates Learjet Model 55 AFMS for the J.E.T. FC-550 autopilot/flight director: AFMS WI002, dated 8/25/81, revised 2/15/83 (for airplanes S/N 55-003 through 55-011, incorporating ECR 2524 or AAK 55-81-2, and airplanes S/N 55-012 through 55-042); or AFMS W1003, dated 8/31/81, revised 2/15/83 (for airplanes S/N 55-003 through 55-042, incorporating ECR 2524 and ECR 2525, or AAK 55-83-I; and airplanes S/N 55-043 and 55-126):
1. Add the following limitation and Note:
Flight director VOR enroute and approach operations are prohibited.
NOTE: Autopilot-coupled VOR operations and raw data displays are not affected and may be used.
2. Add the following limitation:For autopilot VOR approach, the flaps must be lowered to 8 degrees or more.
E. In order to comply with the applicable requirements of paragraph A., B., C., or D., above, a copy of this AD may be used as a temporary amendment to the AFMS and carried in the airplane as part of the AFMS until replaced by the appropriate FAA-approved Gates Learjet published temporary Flight Manual (TFM) Supplement Change. These include:
1. TFM Supplement Change to AFMS W1029 for the Models 35/36 series with J.E.T. FC-530 autopilot/flight director: TFM 86-1, dated 4/1/86.
2. TFM Supplement Change to AFMS T1204 for the Models 35A/36A with J.E.T. FC-535 autopilot/flight director: TFM 86-2, dated 4/1/86.
3. TFM Supplement Change to AFMS WI001 for the Model 55 with J.E.T. FC-550 autopilot/flight director: TFM 86-3, dated 4/1/86.
4. TFM Supplement Change to AFMS WI 002 and AFMS WI 003 for the Model 55 with J.E.T. FC-550 autopilot/flight director: TFM 86-4, dated 4/1/86.
F. Installation of the modification described in Gates Learjet Service Bulletins SB35/36-22-5 or SB55-22-2, both dated 1/5/87, as applicable, constitutes terminating action for the requirements of this AD.
G. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, Wichita Aircraft Certification Office, FAA, Central Region.
All persons affected by this directive who have not already received the appropriate Temporary Airplane Flight Manual Supplement Changes and other service information from the manufacturer may obtain copies upon request to Gates Learjet Corporation, P.O. Box 7707, Wichita, Kansas 67277. The service information may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, Central Region, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas.
This amendment becomes effective March 9, 1987.