Airworthiness Directive · Amendment 39-17931 · Landing gear
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001, 4003 through 4418 inclusive, 4422 and 4423.
We are superseding Airworthiness Directive (AD) 2011-15-09 for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. AD 2011-15-09 required repetitive inspections for proper operation of the main landing gear (MLG) alternate extension system (AES), and corrective actions if necessary. This new AD requires, for certain airplanes, new repetitive inspections for proper operation of the MLG AES, and corrective actions if necessary. This new AD also requires eventually replacing the MLG AES cam mechanism assembly with a new assembly, which terminates the repetitive inspections for those airplanes. This AD was prompted by a determination that, for certain airplanes not affected by AD 2011-15-09, a different MLG AES cam mechanism assembly was installed, resulting in input lever fractures and inability to open the MLG door; those assemblies could be subject to the same unsafe condition in AD 2011-15-09. We are issuing this AD to prevent improper operation of the cam mechanism or rupture of the door release cable, which could result in loss of control of the airplane during landing.
This paragraph restates the requirement in paragraph (i) of AD 2011-15-09, Amendment 39-16756 (76 FR 42033, July 18, 2011), with revised service information. For airplanes with a MLG AES cam mechanism assembly having part number (P/N) 48510-1: Within 50 flight hours or 10 days after August 2, 2011 (the effective date of AD 2011-15-09, Amendment 39-16756 (76 FR 42033, July 18, 2011)), whichever occurs first, do a detailed inspection for proper operation of the MLG AES cam mechanism, in accordance with paragraph A) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. As of the effective date of this AD, use only Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. Repeat the inspection thereafter at intervals not to exceed 50 flight hours or 10 days, whichever occurs first.
(1) If the cam mechanism is found to reset to the normal rested position without any sticking or binding, it is operating properly.
(2) If the cam mechanism has not reset to its normal rested position, or if any sticking or binding is observed, before further flight, remove the cam assembly, in accordance with paragraph A) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012, and do the actions in paragraph (g)(2)(i) or (g)(2)(ii) of this AD. As of the effective date of this AD, use only Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
(i) Repair the cam mechanism assembly, including doing detailed inspections for discrepancies (an inspection to determine proper operation, an inspection for damage, an inspection for corrosion and cadmium coating degradation, and inspections to determine dimensions are within the limits specified in paragraph B) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160 Issue 6, dated June 27, 2012, in accordance with paragraph B) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; and install the repaired cam assembly in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. As of the effective date of this AD, use only Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
(ii) Install a new or serviceable cam assembly, in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. As of the effective date of this AD, use only Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
(3) If the cam mechanism is found damaged or inoperative during the repair specified in paragraph (g)(2)(i) of this AD; or if any discrepancies are found and Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011, or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012, does not specify repairs for those discrepancies; or repairs specified in paragraph (g)(2)(i) of this AD cannot be accomplished: Before further flight, accomplish paragraph (g)(3)(i) or (g)(3)(ii) of this AD.
(i) Repair and reinstall using a method approved by the Manager, New York ACO, ANE-170, Engine and Propeller Directorate, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.
(ii) Install a new or serviceable cam assembly, in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 3, dated February 15, 2011; or Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. As of the effective date of this AD, use only Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012, to install the cam assembly.
For airplanes with a MLG AES cam mechanism assembly having P/N 48510-3: Within 1,800 flight hours or 9 months after installation of the assembly, whichever occurs first after the effective date of this AD, do a detailed inspection for proper operation of the MLG AES cam mechanism, in accordance with paragraph A) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012. Repeat the inspection thereafter at intervals not to exceed 600 flight hours or 3 months, whichever occurs first.
(1) If the cam mechanism is found to reset to the normal rested position without any sticking or binding, it is operating properly.
(2) If the cam mechanism has not reset to its normal rested position, or if any sticking or binding is observed, before further flight, remove the cam assembly, in accordance with paragraph A) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012, and do the actions required by paragraphs (h)(2)(i) or (h)(2)(ii) of this AD.
(i) Repair the cam mechanism assembly, including doing detailed inspections for discrepancies (an inspection to determine proper operation, an inspection for damage, an inspection for corrosion and cadmium coating degradation, and inspections to determine dimensions are within the limits specified in paragraph B) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012), in accordance with paragraph B) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012; and install the repaired cam assembly in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
(ii) Install a new or serviceable cam assembly, in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
(3) If the cam mechanism is found damaged or inoperative during the repair specified in paragraph (h)(2)(i) of this AD; or if any discrepancies are found and Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012, does not specify repairs for those discrepancies; or repairs specified in paragraph (h)(2)(i) of this AD cannot be accomplished: Before further flight, do the applicable actions required by paragraph (h)(3)(i) or (h)(3)(ii) of this AD.
(i) Repair and reinstall using a method approved by the Manager, ANE-170, New York ACO, FAA, or TCCA; or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.
(ii) Install a new or serviceable cam assembly, in accordance with paragraph C) of Bombardier Repair Drawing 8/4-32-0160, Issue 6, dated June 27, 2012.
This paragraph provides credit for actions required by paragraphs (g) and (h) of this AD, if those actions were performed before the effective date of this AD using Bombardier Repair Drawing 8/4-32-0160, Issue 5, dated June 6, 2012, which is not incorporated by reference in this AD.
Within 6,000 flight hours or 36 months after the effective date of this AD, whichever occurs first, replace any MLG AES cam mechanism assembly having P/N 48510-1 or P/N 48510-3 with a new MLG AES cam mechanism assembly having P/N 48510-5, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-32-100, Revision A, dated August 30, 2012. Accomplishing this replacement terminates the repetitive inspections required by this AD.
This paragraph provides credit for actions required by paragraph (j) of this AD, if those actions were performed before the effective date of this AD using Bombardier Service Bulletin 84-32-100, dated August 15, 2012, which is not incorporated by reference in this AD.
