AD 99-18-16 Airworthiness Directives; Boeing Model 747-400, 757-200, 767-200, and 767-300 Series Airplanes

Models named: 747-400 series, 757-200 series, 767-200, 767-3300 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-400 series airplanes, line numbers 1121 through 1177 inclusive; Model 757-200 series airplanes, line numbers 761 through 828 inclusive; and Model 767-200 and 767-3300 series airplanes, line numbers 668 through 723 inclusive; equipped with either a modular avionics warning electronic assembly (MAWEA) or a warning electronics unit (WEU) power supply, part number 285T0035- 201; certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To detect and correct failure of the MAWEA or WEU, which could result in a gradual degradation and eventual loss of visual, aural, or tactile alerts to the flightcrew, accomplish the following: Model 747-400 Series Airplanes: Checks and Functional Tests (a) For Model 747-400 series airplanes: Within 15 days after the effective date of this AD, check the status page of the engine indication and crew alerting system (EICAS) for any MAWEA failure; and perform the system functional tests required by paragraphs (a)(1), (a)(2), (a)(3), (a)(4), and (a)(5) of this AD to detect loss of any visual, aural, or tactile alert. Thereafter, repeat the EICAS status page check and the system functional tests before each flight. Note 2: The following tests are an abbreviated version of Section 3, Work Instructions, of Boeing Service Bulletin 747-31- 2288, dated December 17, 1998, and Revision 1, dated January 28, 1999. (1) Perform a takeoff (T/O) configuration warning test to check the T/O configuration warning card, master monitors A and B, and left and right aural synthesizer cards. (i) Set the parking brake. (ii) Initiate the following central maintenance computer (CMC) ground test--31 indication/recording: T/O warning. (iii) Verify that the left and right master warning lights (MWL) illuminate and the siren is heard from both the left and right speakers. (2) Perform an altitude alert test to check the crew alert module. (i) Verify the parking brake is still set. (ii) Set the selected altitude on the mode control panel (MCP) to approximately 400 feet above the current altitude. (iii) Verify that the box around the current altitude on the altitude tape becomes bright white. (iv) Set the selected altitude on the MCP to 10,000 feet. (v) Verify the aural warning owl is not activated. (3) Perform a stall warning test to check the left and right stall management module cards. (i) Ensure that the air data computers (ADC) are operational. (ii) Initiate the following CMC ground test--27 stall warning: Left. (iii) Verify that both stick shakers activate. (iv) Initiate the following CMC ground test--27 stall warning: Right. (v) Verify that both stick shakers activate. (4) Perform an autopilot (A/P) disconnect test to check the left and right clacker wailer card. (i) Press and hold the A/P disconnect on either control wheel. (ii) Verify the wailer aural is heard over the left and right speakers and MWL's. (iii) Release the A/P disconnect switch. (5) Perform a MAWEA card light emitting diode (LED) test per Airplane Maintenance Manual (AMM) task 31-51-00-715-014, ``MAWEA operational test,'' to verify that no red LED on the MAWEA circuit cards illuminate. Note 3: The EICAS status page check and the system functional tests are considered maintenance functions that require airplane log book entree and maintenance release prior to flight. Model 757-200, 767-200, and 767-300 Series Airplanes: Checks and Functional Tests (b) For Model 757-200, 767-200, and 767-300 series airplanes: Within 15 days after the effective date of this AD, check the status page of the EICAS for any WEU failure; and perform the Work Instructions in Section 3, Part 1, of Boeing Service Bulletin 757- 31-0066, Revision 1, dated December 17, 1998 (for Model 757-200 series airplanes); or Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998 (for Model 767-200 and 767-300 series airplanes); as applicable; to detect loss of any visual, aural, or tactile alert. Thereafter, repeat the EICAS status page check and the Work Instructions in Section 3, Part 1 of the applicable service bulletin before each flight. Note 4: The EICAS status page check and performance of the Work Instructions in Section 3, Part 1, of the applicable service bulletin are considered maintenance functions that require airplane log book entree and maintenance release prior to flight. Corrective Action (c) If any failure of the MAWEA or WEU, as applicable, or the loss of any visual, aural, or tactile alert is detected during any test required by either paragraph (a) or (b) of this AD, prior to further flight, replace the power supply of the MAWEA or WEU with a new power supply, P/N 285T0035-202 Mod A, in accordance with either Boeing Service Bulletin 747-31-2288, dated December 17, 1998, or Revision 1, dated January 28, 1999 (for Model 747-400 series airplanes); 757-31-0066, Revision 1, dated December 17, 1998 (for Model 757-200 series airplanes); or 767-31-0106, Revision 1, dated December 17, 1998 (for Model 767-200 and 767-300 series airplanes); as applicable. Accomplishment of this action constitutes terminating action for the repetitive inspection requirements of this AD. Note 5: Page 59 of Boeing Service Bulletin 747-31-2288, Revision 1, dated January 28, 1999, incorrectly references the Boeing 767 AMM as the appropriate source of service information for accomplishment of the removal and installation of the power supply. However, the correct reference is the Boeing 747 AMM. Spares (d) As of the effective date of this AD, no person shall install a MAWEA or WEU power supply, part number 285T0035-201, on any airplane. Optional Terminating Action (e) Replacement of the power supply of the MAWEA or WEU with a new power supply, P/N 285T0035-202 Mod A, in accordance with Boeing Service Bulletin 747-31-2288, dated December 17, 1998, or Revision 1, dated January 28, 1999 (for Model 747-400 series airplanes); 757- 31-0066, Revision 1, dated December 17, 1998 (for Model 757-200 series airplanes); or 767-31-0106, Revision 1, dated December 17, 1998 (for Model 767-200 and 767-300 series airplanes); as applicable; constitutes terminating action for the repetitive system functional tests and EICAS status page checks required by this AD. Alternative Methods of Compliance (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 6: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, Seattle ACO. [[Page 47656]] Special Flight Permits (g) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Incorporation by Reference (h) The replacement, if accomplished, shall be done in accordance with Boeing Service Bulletin 747-31-2288, dated December 17, 1998, or Boeing Service Bulletin 747-31-2288, Revision 1, dated January 28, 1999; Boeing Service Bulletin 757-31-0066, Revision 1, dated December 17, 1998; or Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (i) This amendment becomes effective on September 16, 1999. Issued in Renton, Washington, on August 24, 1999. Vi L. Lipski, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-22532 Filed 8-31-99; 8:45 am] BILLING CODE 4910-13-P