Airworthiness Directive · Amendment 39-12001 · Boeing Model 777 Series Airplanes
Boeing Model 777 Series Airplanes
All Model 777 series airplanes, 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 (e) 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.
This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 777 series airplanes, that currently requires repetitive testing of the engine fire shutoff switch (EFSS) to determine if the override mechanism and the switch handle are operational, and replacement of the EFSS, if necessary. That AD also requires, for certain airplanes, installation of a collar on a specific circuit breaker of the standby power management panel, and installation of placards to advise the flightcrew that the override mechanism must be pushed in order to pull the fire switch. This amendment adds various actions that would terminate the repetitive testing requirements. This amendment is prompted by a report indicating that a solenoid and an override mechanism of the EFSS were not operational due to overheating of the solenoid. The actions specified by this AD are intended to prevent damage to the EFSS solenoid and to the override mechanism, and consequent failure of the EFSS due to overheating of the solenoid; such failure could result in the inability of the flightcrew to discharge the fire extinguishing agent in the event of an engine fire.
To prevent damage to the engine fire shutoff switch (EFSS) solenoid and to the override mechanism, and consequent failure of the EFSS, which could result in the inability of the flightcrew to discharge the fire extinguishing agent in the event of an engine fire, accomplish the following:
(a) For all airplanes: Within 14 days after May 27, 1997 (the effective date of AD 97-10-11, amendment 39-10023), perform a test of the EFSS of both the left- and right-hand engines to determine if the override mechanism and the switch handle are operational, in accordance with Boeing Alert Service Bulletin 777-26A0012, dated May 1, 1997.
(1) If the override mechanism and the switch handle of the EFSS are operational, prior to further flight, accomplish the requirements of paragraph (a)(1)(i) or (a)(1)(ii) of this AD, as applicable, in accordance with the alert service bulletin.
(i) For Group 1 airplanes identified in the alert service bulletin: Install a collar on circuit breaker C26612 of panel P310 of the standby power management panel. Following accomplishment of this installation, prior to further flight, install placards near the EFSS of both engines and near the auxiliary power unit (APU) EFSS to advise the flightcrew that the override mechanism must be pushed in order to pull the fire switch.
(ii) For Group 2 airplanes identified in the alert service bulletin: Ensure that a collar is installed on circuit breaker C26612 of panel P310 of the standby power management panel. If a collar is not installed, prior to further flight, install a collar on circuit breaker C26612 of panel P310 of the standby power management panel.
(2) If the override mechanism or the switch handle of the EFSS is not operational, prior to further flight, replace the EFSS with a new or serviceable EFSS, in accordance with the alert service bulletin.
(b) For all airplanes: Repeat the requirements of paragraph (a) of this AD thereafter at intervals not to exceed 500 flight hours.
(c) For all airplanes: Within 2 years after the effective date of this AD, accomplish the actions specified in either paragraph (c)(1) or (c)(2) of this AD, in accordance with Boeing Alert Service Bulletin 777-26A0009, dated October 23, 1997.
(1) Verify that the airplane does not have an engine fire control module having part number (P/N) 233W6201-1, and that the airplane configuration is equivalent to that specified in the alert service bulletin. If the airplane meets the requirements in this paragraph, no further action is required by this AD.
(2) If the airplane does not meet the requirements specified in paragraph (c)(1) of this AD: Remove the engine fire control module, P/N 233W6201-1, and replace it with P/N 233W6201-5; activate the circuit breaker C26612 in the P310 panel; and remove the placards in the flight deck compartment; in accordance with the alert service bulletin. Accomplishment of this paragraph constitutes terminating action for the repetitive testing requirements of paragraph (b) of this AD.
(d) As of the effective date of this AD, no person shall install an engine fire control module, P/N 233W6201-1, or engine fire switches P/N S231W263-1 or -2, on any airplane.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
