Airworthiness Directive · Amendment 39-11526 · Bombardier Model DHC-7-100 Series Airplanes
Bombardier Model DHC-7-100 Series Airplanes
Superseded. A later AD replaced this one: AD 2000-02-07 R1. Comply with the one in force.
All Model DHC-7-100 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 (d) 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 adopts a new airworthiness directive (AD), applicable to all Bombardier Model DHC-7-100 series airplanes, that requires repetitive high frequency eddy current inspections to detect cracks on the locking pin fittings of the baggage door and locking pin housings of the fuselage; repetitive detailed visual inspections to detect cracks of the inner door structure on all four door locking attachment fittings; and corrective actions, if necessary. In lieu of accomplishing the corrective actions, this amendment also provides a temporary option, for certain cases, for revising the Airplane Flight Manual (AFM), and installing a placard. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to detect and correct fatigue cracking of the baggage door fittings and the support structure, which could result in structural failure, and consequent rapid decompression of the airplane during flight.
To detect and correct fatigue cracking in the baggage door fittings and the support structure, which could result in structural failure, and consequent rapid decompression of the airplane during flight, accomplish the following:
(a) At the latest of the times specified in paragraphs (a)(1) and (a)(2) of this AD, perform a high frequency eddy current inspection to detect fatigue cracks of the locking pin fittings of the baggage door and locking pin housings of the fuselage; and a detailed visual inspection to detect fatigue cracks of the inner door structure on all four locking attachment fittings of the baggage door; in accordance with de Havilland Temporary Revision (TR) 5-100, dated December 23, 1998, for Supplementary Inspection Task 52-1 to the de Havilland Dash 7 Maintenance Manual PSM 1-7-2. Thereafter, repeat the inspections at intervals not to exceed 1,000 flight cycles.
(1) Inspect prior to the accumulation of 12,000 total flight cycles.
(2) Inspect within 600 flight cycles or 3 months after the effective date of this AD, whichever occurs later.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(b) If any crack is detected during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish the requirements of paragraphs (b)(1) and (b)(2) of this AD, as applicable, except as provided in paragraph (c) of this AD. For operators that elect to accomplish the actions specified in paragraph (c) of this AD: After accomplishment of the replacement required by paragraph (b)(1) or (b)(2) of this AD, the AFM revision and placard required by paragraph (c) of this AD may be removed.
(1) If a crack is detected in a baggage door locking pin fitting or fuselage locking pin housing: Replace the fitting or housing with a new fitting or housing, as applicable, in accordance with de Havilland Dash 7 Maintenance Manual PSM 1-7-2.
(2) If a crack is detected in the inner baggage door structure at the locking attachment fittings: Replace the structure with a new support structure in accordance with de Havilland Dash 7 Maintenance Manual PSM 1-7-2, or repair in accordance with a method approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate, or the Transport Canada Civil Aviation (or its delegated agent). For a repair method to be approved by the Manager, New York ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
(c) For airplanes on which only one baggage door stop fitting or its support structure is found cracked at one location, and on which the pressurization system “Dump” function is operational: Prior to further flight, accomplish the requirements of paragraphs (c)(1) and (c)(2) of this AD. Within 1,000 flight cycles after accomplishment of the requirements of paragraphs (c)(1) and (c)(2) of this AD, accomplish the requirements of paragraph (b)(1) or (b)(2) of this AD, as applicable.
(1) Revise the Limitations Section of the FAA-approved DHC-7 Airplane Flight Manual (AFM), PSM 1-71A-1A, to include the following statement. This AFM revision may be accomplished by inserting a copy of this AD into the AFM.
“Flight is restricted to unpressurized flight below 10,000 feet mean sea level (MSL). The airplane must be operated in accordance with DHC-7 AFM, PSM 1-71A-1A, Supplement 20.”
(2) Install a placard on the cabin pressure control panel or in a prominent location that states the following:
“DO NOT PRESSURIZE THE AIRCRAFT UNPRESSURIZED FLIGHT PERMITTED ONLY IN ACCORDANCE WITH DHC-7 AFM PSM 1-71A-1A, SUPPLEMENT 20 FLIGHT ALTITUDE LIMITED TO 10,000 FEET MSL OR LESS.”
