Airworthiness Directive · Amendment 39-14890 · Bombardier Model DHC-8-400 Series Airplanes
Bombardier Model DHC-8-400 Series Airplanes
This AD applies to Bombardier Model DHC-8-400 series airplanes, certificated in any category; serial numbers 4001 and 4003 through 4087 inclusive; equipped with main landing gear (MLG) uplock assembly part numbers (P/Ns) 46500-3 and -5.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Bombardier Model DHC-8-400 series airplanes. That AD currently requires revising the airplane flight manual (AFM) to advise the flightcrew of appropriate procedures to follow in the event that a main landing gear (MLG) fails to extend following a gear-down selection. That AD also currently requires repetitive replacement of the left and right MLG uplock assemblies with new assemblies; and an inspection of the left and right MLG uplock rollers for the presence of an inner low friction liner, and corrective actions if necessary. This new AD revises the requirement for replacing the left and right MLG uplock assemblies by allowing replacement with alternative parts. For a certain MLG uplock assembly, this new AD requires repetitive inspections of the uplock hatch lower jaw for the presence of a wear groove and replacement with an improved part if necessary. For a certain MLG uplock assembly, this new AD requires repetitive inspections of the uplock roller to ensure that it rotates freely and replacement with a new part if necessary. This new AD allows optional replacement of the left and right MLG uplock assemblies with improved parts, which ends the requirements of the AFM revision and repetitive replacement and inspections. This new AD removes airplanes from the applicability. This AD results from development of a terminating action. We are issuing this AD to ensure that the flightcrew has the procedures necessary to address failure of an MLG to extend following a gear-down selection; and to detect and correct such failure, which could result in a gear-up landing and possible injury to passengers and crew.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 3 days after April 23, 2002 (the effective date of AD 2002-08-05), amend all copies of the FAA-approved Bombardier Series 400 AFM, PSM 1-84-1A (for Models 400, 401, and 402), by adding the following procedure to the Limitations section of the AFM and opposite page 4-21-1 of the AFM; and advise all flightcrew members of these changes. (The revision may be accomplished by inserting a copy of this AD into the Limitations section of the AFM and affected paragraphs of the AFM.):
“If ONE main landing gear fails to extend after performing landing gear extension per normal procedures given in paragraph 4.3.7 and alternate extension procedures per paragraph 4.21.1 of the AFM:
1. Visually confirm that the affected gear has not extended and that the associated doors have opened.
2. Ensure No. 2 hydraulic system pressure and quantity are normal and the following landing gear advisory lights are illuminated: selector lever amber, gear green locked down (nose and non-affected main gear), red gear unlocked (affected main gear) and all amber doors open.
3. NOSE L/G RELEASE handle—Return to the stowed position.
4. LANDING GEAR ALTERNATE EXTENSION door—Close fully.
5. MAIN L/G RELEASE handle—Return to the stowed position.
6. LANDING GEAR ALTERNATE RELEASE door—Close fully.
7. LANDING GEAR lever—DN.
8. L/G DOWN SELECT INHIBIT SW—Normal and guarded. Check amber doors open advisory lights out (nose and non-affected main gear) and LDG GEAR INOP caution light out.
9. LANDING GEAR lever—UP Check all gear, door and LANDING GEAR lever advisory lights out.
10. With minimum delay, LANDING GEAR lever—DN. Check 3 green gear locked down advisory lights illuminate, all amber doors open, red gear unlocked and selector lever amber advisory lights out.
11. Items 9 and 10 may be repeated in an effort to achieve 3 gear down and locked.
Should the LDG GEAR INOP caution light illuminate, or loss of no. 2 hydraulic system pressure or quantity, or any abnormality in landing gear system indication other than those associated with the affected main landing gear be experienced, see paragraph 4.21.1 ALTERNATE LANDING GEAR EXTENSION.”
Accomplishing the actions specified in paragraph (k) of this AD terminates the requirements of this paragraph, and after the replacement has been done, the AFM limitation may be removed from the AFM.
At the later of the times specified in paragraph (g)(1) or (g)(2) of this AD: Replace the left and right MLG uplock assemblies, P/N 46500-3, with new or overhauled uplock assemblies having P/N 46500-3, -5, -7, or -9 according to a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent). Using Tasks 32-31-21-000-801 and 32-31-21-400-801 of Chapter 32-31-21 of Bombardier Q400 Dash 8 Aircraft Maintenance Manual (AMM), PSM 1-84-2, is one approved method. For any uplock assembly having P/N 46500-3, repeat the replacement thereafter at intervals not to exceed 2,500 flight hours or 3,000 flight cycles, whichever occurs earlier. For any uplock assembly having P/N 46500-5, do the actions required by paragraph (i) of this AD. Replacing an uplock assembly with a new or overhauled uplock assembly having P/N 46500-7 or -9 terminates the requirements of this paragraph, for that uplock assembly only.
(1) Before the accumulation of 2,500 total flight hours or 3,000 total flight cycles on an uplock assembly, whichever occurs earlier; or
(2) Within 14 days after April 23, 2002.
Within 30 days after April 23, 2002, do a general visual inspection of the left and right MLG uplock rollers for the presence of an inner low friction (black-colored) liner, in accordance with the Accomplishment Instructions of Bombardier DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002; and, before further flight, do the actions required by paragraph (h)(1) or (h)(2) of this AD.
Note 1: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
(1) If a low friction liner is present, reinstall the existing uplock roller; or install a new uplock roller, P/N 46575-1, having a low friction liner; on the shock strut of the MLG in accordance with the service bulletin.
(2) If a low friction liner is not present, replace the existing uplock roller with a new uplock roller, P/N 46575-1, having a low friction liner, on the shock strut of the MLG in accordance with the service bulletin. After the effective date of this AD, if the low friction liner is not present, replace the uplock roller in accordance with paragraph (i)(2) of this AD.
Note 2: Bombardier DHC-8 Alert Service Bulletin A84-32-15, dated February 4, 2002, references Chapter 32-11-01 of Bombardier Q400 Dash 8 AMM, PSM 1-84-2, as an additional source of service information for procedures to replace an MLG uplock roller.
(i) For any MLG uplock assembly having P/N 46500-5, do the inspections specified in paragraphs (i)(1) and (i)(2) of this AD at the later of the following compliance times: Before the accumulation of 2,500 total flight hours or 3,000 total flight cycles on the uplock assembly, whichever occurs first; or within 90 days after the effective date of this AD. Repeat the inspections thereafter at intervals not to exceed 400 flight hours or 480 flight cycles, whichever occurs first. Replacement of an uplock assembly in accordance with paragraph (i)(1) of this AD terminates the repetitive inspections of paragraphs (i)(1) and (i)(2) of this AD, for that uplock assembly only.
(1) Do a detailed dimensional inspection of the surface of the uplock hatch lower jaw for the presence of a wear groove and measure the wear groove depth to an accuracy of 0.001 inch, according to a method approved by either the Manager, New York ACO; or TCCA (or its delegated agent). Using Task 32-31-21-220-801 of the Bombardier Q400 Dash 8 AMM, PSM 1-84-2, is one approved method. If the groove depth exceeds 0.007 inch, before further flight, replace the uplock assembly with a new or serviceable uplock assembly, P/N 46500-7 or -9, according to a method approved by either the Manager, New York ACO; or TCCA (or its delegated agent). Using Tasks 32-31-21-000-801 and 32-31-21-400-801 of Chapter 32-31-21 of the Bombardier Q400 Dash 8 AMM, PSM 1-84-2, is one approved method.
(2) Do a general visual inspection of the uplock roller, P/N 46575-1, of the MLG uplock assembly to ensure that it rotates freely. If the uplock roller does not rotate freely, before further flight, replace the uplock roller with a new uplock roller, P/N 46575-1, in accordance with Bombardier Temporary Revision (TR) 32-191 and Bombardier TR 32-192, both dated May 29, 2006, both to Bombardier Q400 Dash 8 AMM.
(j) When the information in Bombardier TR 32-191 and Bombardier TR 32-192, both dated May 29, 2006, is included in the AMM, the AMM is approved as an acceptable method of compliance for the replacement specified in paragraph (i)(2) of this AD.
Replacing the left and right MLG uplock assemblies having P/N 46500-3 or -5 with new or overhauled uplock assemblies having P/N 46500-7 or -9 according to a method approved by either the Manager, New York Aircraft Certification Office (ACO), FAA; or Transport Canada Civil Aviation (TCCA) (or its delegated agent); terminates the requirements of paragraphs (f), (g), (h), and (i) of this AD, as applicable. Using Tasks 32-31-21-000-801 and 32-31-21-400-801 of Chapter 32-31-21 of Bombardier Q400 Dash 8 Aircraft Maintenance Manual (AMM), PSM 1-84-2, is one approved method. After the replacements have been done, the AFM limitation required by paragraph (f) of this AD may be removed from the AFM.
