Airworthiness Directive · Amendment 39-13938 · Boeing Model 767-300 Series Airplanes
Boeing Model 767-300 Series Airplanes
This AD applies to Boeing Model 767-300 series airplanes, certificated in any category; as listed in Boeing Alert Service Bulletin 767-26A0127, dated July 17, 2003.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 767-300 series airplanes. This AD requires repetitive functional tests and repetitive replacements of the auxiliary power unit (APU) and engine fire shutoff switches. This proposal also provides an optional terminating action for the repetitive functional tests and replacements. This AD is prompted by a report of the failure of the engine fire shutoff switch in the engine fire control module. We are issuing this AD to prevent mineral build-up on the APU and engine fire shutoff switches, which could lead to the switches failing to discharge fire suppressant to the affected fire zone and result in an uncontrolled engine or APU fire and consequent loss of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Alert Service Bulletin 767-26A0127, dated July 17, 2003.
At the later of the compliance times specified in paragraphs (g)(1) and (g)(2) of this AD, do a functional test of the APU and engine fire shutoff switches, in accordance with the service bulletin. Repeat the functional test thereafter at intervals not to exceed 18 months.
(1) Within 18 months since the date of issuance of the original Airworthiness Certificate or the original Export Certificate of Airworthiness.
(2) Within 90 days after the effective date of this AD.
If any APU or engine fire shutoff switch fails during any functional test required by paragraph (g) or (k) of this AD, before further flight, replace the switch with a new or serviceable switch, in accordance with the service bulletin. Repeat the switch replacement thereafter at intervals not to exceed 36 months.
(i) Within 18 months after the effective date of this AD, replace all APU and engine fire shutoff switches that have not been previously replaced in accordance with paragraph (h) of this AD with new or serviceable switches, in accordance with the service bulletin. Repeat the switch replacement thereafter at intervals not to exceed 36 months.
Accomplishment of the actions specified in paragraphs (j)(1) and (j)(2) of this AD, terminates the repetitive requirements of paragraphs (g), (h), and (i) of this AD, except as provided by paragraph (k) of this AD.
(1) Deactivate the Lucas humidifier, part number (P/N) M01AA0101, M01AB0101, M01AB0102, or M01AB0103, in accordance with the service bulletin.
(2) Before further flight following the deactivation specified in paragraph (j)(1) of this AD, replace all APU and engine fire shutoff switches with new or serviceable switches, in accordance with the service bulletin.
For any airplane on which Lucas humidifier, P/N M01AA0101, M01AB0101, M01AB0102, or M01AB0103, is reactivated after the effective date of this AD: Do the actions required by paragraphs (k)(1) and (k)(2) of this AD at the specified compliance times.
(1) Within 18 months after reactivating the humidifier, and thereafter at intervals not to exceed 18 months, do the functional tests required by paragraph (g) of this AD.
(2) Within 36 months after reactivating the humidifier, and thereafter at intervals not to exceed 36 months, replace all APU and engine fire shutoff switches that have not been previously replaced in accordance with paragraph (h) of this AD. Do the replacements in accordance with paragraph (i) of this AD.
