92-16-51 EMBRAER: Amendment 39-8355. Docket No. 92-NM-152-AD.
Applicability: All Model EMB-120 series airplanes, certificated in any category.
To prevent an inoperative backup flight idle stop system and potential engine failure, accomplish the following:
(a) Within 5 days after the effective date of this AD, and thereafter prior to the first flight of each day, accomplish paragraph (a)(1) or (a)(2) of this AD, as applicable:
(1) For airplanes on which an inspection window has been installed on the left lateral console panel that permits visibility of the flight idle stop solenoid circuit breakers: Using an appropriate light source, perform a visual check to verify that both "FLT IDLE STOP SOL" circuit breakers CB0582 and CB0583 for engine 1 and engine 2 are closed.
NOTE 1: This check may be performed by a flight crew member.
NOTE 2: Instructions for installation of an inspection window can be found in EMBRAER Information Bulletin 120-076-0003, dated November 19, 1991; or EMBRAER Service Bulletin 120-076- 0014, dated July 29, 1992.
(2) For airplanes on which an inspection window has not been installed on the left lateral console panel: Perform a visual inspection to verify that both "FLT IDLE STOP SOL" circuit breakers CB0582 and CB0583 for engine 1 and engine 2 are closed.
(b) As a result of the check or inspection performed in accordance with paragraph (a) of this AD: If circuit breakers CB0582 and CB0583 are not closed, prior to further flight, reset them and perform the functional test specified in paragraph (c) of this AD.
(c) Within 5 days after the effective date of this AD and thereafter at intervals not to exceed 75 hours time-in-service, or immediately following any maintenance action where the power levers are moved with the airplane on jacks, conduct a functional test of the backup flight idle stop system for engine 1 and engine 2 by performing the following steps:
(1) Move both power levers to the "MAX" position.
(2) Turn the aircraft power select switch on.
(3) Open both "AIR/GROUND SYSTEM" circuit breakers CB0283 and CB0286 to simulate in-flight conditions with weight-off-wheels. Wait for at least 15 seconds, then move both power levers back toward the propeller reverse position with the flight idle gate triggers raised. Verify that the power lever for each engine cannot be moved below the flight idle position, even though the flight idle gate trigger on each power lever is raised.
(4) If the power lever can be moved below the flight idle position, prior to further flight, restore the backup flight idle stop system to the configuration specified in EMBRAER Service Bulletin 120-076-0009, Change No. 4, dated November 1, 1990, and perform a functional test.
NOTE: If the power lever can be moved below flight idle, this indicates that the backup flight idle stop system is inoperative.
(5) Move both power levers to the "MAX" position.
(6)Close both "AIR/GROUND SYSTEM" circuit breakers CB0283 and CB0286. Wait for at least 15 seconds, then move both power levers back toward the propeller reverse position with the flight idle gate triggers raised. Verify that the power lever for each engine can be moved below the flight idle position.
(7) If either or both power levers cannot be moved below the flight idle position, prior to further flight, inspect the backup flight idle stop system and the flight idle gate system, and accomplish either paragraph (c)(7)(i) or (c)(7)(ii) of this AD, as applicable:
(i) If the backup flight idle stop system is failing to disengage with weight- on-wheels, prior to further flight, restore the system to the configuration specified in EMBRAER Service Bulletin 120-076-0009, Change No. 4, dated November 1, 1990.
(ii) If the flight idle gate system is failing to open even though the trigger is raised, prior to further flight, repair in accordance with the EMBRAER Model EMB-120maintenance manual.
(8) Turn the power select switch off. The functional test is completed.
(d) Within 10 days after accomplishing the initial visual inspection/check and initial functional test required by paragraphs (a) and (c) of this AD, report the results of those tests, positive or negative, to the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate, 1669 Phoenix Parkway, Suite 210C, Atlanta, Georgia 30349; fax (404) 991-3606. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.
(e) 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, Atlanta ACO, FAA, Small 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, Atlanta ACO.
NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.
(f) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.
(g) The restoration procedure shall be done in accordance with EMBRAER Service Bulletin 120-076-0009, Change No. 4, dated November 1, 1990. 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 EMBRAER Aircraft Corporation, 276 SW. 34th Street, Fort Lauderdale, Florida 33315. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate, 1669 Phoenix Parkway, Suite 210C, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on September 23, 1992, to all persons except those persons to whom it was made immediately effective by telegraphic AD T92-16-51, issued July 29, 1992, which contained the requirements of this amendment.