AD 2021-09-17
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bombardier | Various | Airworthiness Directives; Bombardier, Inc., Airplanes |
Unsafe Condition
MFS PCUs with improperly configured piston seals, which could cause degraded proportional lift dumping (PLD) function. This condition could hinder the airplane from carrying out an emergency descent, resulting in structural damage and injury to occupants.
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Required Actions
Do an inspection to determine if affected MFS PCUs are installed on the airplane in accordance with Paragraph 2.B. of Bombardier Service Bulletin 100-27-17, Revision 03, dated June 19, 2020; or Bombardier Service Bulletin 350-27-010, dated June 19, 2020; as applicable. A review of airplane maintenance records is acceptable in lieu of this inspection if the serial number of the MFS PCU can be conclusively determined. If an affected MFS PCU is found, replace it with a serviceable MFS PCU in accordance with the applicable service bulletin.
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Compliance Time
Within 12 months after the effective date of this AD
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Affected Aircraft
Bombardier, Inc., Model BD-100-1A10 airplanes, certificated in any category, serial numbers 20003 through 20457 inclusive, and 20501 through 22999 inclusive.
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Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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