“During our investigation of the problem, we determined that the configuration and quality controls over the production of these parts were so deficient that we do not have confidence that the airplane can be operated safely for any period of time,” a new Airworthiness Directive states. The FAA, last week, grounded 222 Learjet Model 45 business jets until their horizontal stabilizer actuator assemblies are replaced. The new AD issued last Wednesday supercedes an earlier one that called for inspection of the assembly. At the heart of the problem is a screw and nut assembly that can get brittle and fail. New parts are expected to be available soon. The original AD was issued after a report of a severe vibration, followed by a rapid nose-down pitch change, by the pilot of one of the eight-seat bizjets. While the tail problems are being tended to, Lear 45 owners might want to take care of another AD concerning the landing gear. New shear pins must be installed in the trunnion assemblies of the main landing gear to prevent a possible gear failure. The AD is effective August 27.
Lear 45s Grounded By Tail Problems
Key Takeaways:
- The FAA has grounded 222 Learjet Model 45 business jets due to critically deficient configuration and quality controls over horizontal stabilizer actuator assemblies, making them unsafe to operate.
- The core issue is a brittle screw and nut assembly in the horizontal stabilizer actuator, which can lead to severe vibration and rapid nose-down pitch changes.
- The new Airworthiness Directive (AD) supersedes an earlier one that only called for inspection, now requiring replacement of the defective parts.
- Lear 45 owners also face another AD effective August 27, requiring new shear pins in the main landing gear to prevent possible failure.
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