Airworthiness Directive · Amendment 39-14361 · Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, and 25F Airplanes
Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, and 25F Airplanes
This AD applies to Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, and 25F airplanes, certificated in any category; having serial numbers 23-003 through 23-099 inclusive, 24-100 through 24-284 inclusive, and 25-003 through 25-153 inclusive.
The FAA is adopting a new airworthiness directive (AD) for certain Learjet Model 23, 24, 24A, 24B, 24B-A, 24C, 24D, 24D-A, 24E, 24F, 24F-A, 25, 25A, 25B, 25C, 25D, and 25F airplanes. This AD requires replacement of the spherical accumulator for the main hydraulic system with a new cylindrical accumulator. For certain airplanes, this AD also requires modification of the accumulator pressure gauge. This AD results from reports of the failure of two thrust reverser accumulators (which are similar to the main hydraulic system's spherical accumulator) and fatigue cracks found on four thrust reverser accumulators. We are issuing this AD to prevent failure of the spherical accumulator for the main hydraulic system, due to fatigue cracking on the threads, which could result in the loss of hydraulic power, damage to the surrounding airplane structure, and loss of airplane control. The failure of the accumulator could also result in injury to any persons in the surrounding area. The loss of hydraulic fluid could also leak onto a potential source of ignition and result in a consequent fire.
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 60 days after the effective date of this AD, replace the spherical accumulator having part number (P/N) 2380025-() or P/N 2380167-() with a new cylindrical accumulator having P/N 2497202-801, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A23/24/25-29-4, Revision 1, dated January 17, 2005.
For airplanes having serial numbers 23-003 through 23-014 inclusive: Prior to or concurrently with the actions in Bombardier Alert Service Bulletin A23/24/25-29-4, Revision 1, dated January 17, 2005, relocate the accumulator pressure gauge in accordance with Learjet Service Kit SK23-215, dated April 4, 1966.
As of the effective date, no spherical accumulator having P/N 2380025-() or P/N 2380167-() may be installed on any airplane.
(i) Replacements done before the effective date of this AD in accordance with Bombardier Alert Service Bulletin A23/24/25-29-4, dated August 20, 2004, are acceptable for compliance with the requirements of paragraph (f) of this AD.
Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
