Airworthiness Directive · Amendment 39-18189 · Fire protection
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001 through 4424 inclusive.
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of corrosion in the low-rate discharge tubes of the fire protection system leading to the forward baggage compartment, and perforation of one or more tubes. This AD requires repetitive checks for leakage of the discharge tubes of the fire protection system. This AD also mandates eventual replacement of all existing aluminum tube assemblies with new, improved corrosion-resistant stainless steel tube assemblies. We are issuing this AD to prevent perforation of the low- rate discharge tubes, which could result in insufficient fire extinguishing agent reaching the forward baggage compartment in the event of a fire, which could result in damage to the airplane and injury to the occupants.
At the applicable time specified in paragraph (g)(1) or (g)(2) of this AD, perform an inspection (integrity check) for leakage of the fire protection tube assemblies of the forward baggage compartment, in accordance with paragraph 3.B., “Procedure,” of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-26-15, Revision A, dated January 15, 2014. If no leakage is found, repeat the inspection at intervals not to exceed 2,000 flight hours or 12 months, whichever occurs first. If any leakage is found, before further flight, do the terminating action required by paragraph (h) of this AD, except as provided by paragraph (i) of this AD.
(1) For airplanes that have accumulated 10,000 total flight hours or more, or have been in service for 60 months or more as of the effective date of this AD: Within 2,000 flight hours or 12 months after the effective date of this AD, whichever occurs first.
(2) For airplanes that have accumulated less than 10,000 total flight hours, and have been in service for less than 60 months, as of the effective date of this AD: Before the accumulation of 12,000 total flight hours or 72 months in service, whichever occurs first.
At the applicable time specified in paragraph (h)(1) or (h)(2) of this AD: Replace all existing aluminum tube assemblies of the forward baggage compartment with new, improved corrosion-resistant stainless steel tube assemblies, in accordance with paragraph 3.B., “Procedure,” of Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-26-15, Revision A, dated January 15, 2014. Accomplishing this replacement terminates the repetitive inspections required by paragraph (g) of this AD.
(1) For airplanes that have accumulated 12,000 total flight hours or more, or have been in service for 72 months or more, as of the effective date of this AD: Within 6,000 flight hours or 36 months after the effective date of this AD, whichever occurs first.
(2) For airplanes that have accumulated less than 12,000 total flight hours, and have been in service for less than 72 months, as of the effective date of this AD: Before the accumulation of 18,000 total flight hours or 108 months in service, whichever occurs first.
(1) As an alternative to the immediate tube assembly replacement following any failed inspection (integrity check) required by paragraph (g) of this AD, the airplane may be returned to service for a maximum of 10 days, provided the conditions specified in paragraphs (i)(1)(i), (i)(1)(ii), and (i)(1)(iii) of this AD are met.
(i) The forward baggage compartment is empty. For ballast purposes, the use of bags (made of glass fiber or Kevlar) of sand or ingots of non-magnetic metals (such as lead) are acceptable.
(ii) The flight compartment and forward baggage compartment are placarded to indicate the forward baggage compartment is inoperative.
(iii) An appropriate entry in the aircraft maintenance log is made.
(2) As an alternative to the immediate tube assembly replacement following any failed inspection (integrity check) required by paragraph (g) of this AD, the airplane may be returned to service for a maximum of 10 days provided no additional leakage is found. Any tubes found with a leak are to be replaced before further flight, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-26-15, dated January 7, 2013.
