Airworthiness Directive 99-19297
one-timeAirworthiness Directives; Learjet Model 23, 24, 25, 28, 29, 31, 55, and 60 Series Airplanes
What this AD requires
This amendment adopts a new airworthiness directive (AD), applicable to certain Learjet Model 23, 24, 25, 28, 29, 31, 55, and 60 series airplanes, that requires a one-time detailed visual inspection of the electrical wire leads of the horizontal stabilizer anti-ice system to verify that the numbers on the wire leads correctly correspond to the numbers on the connected airframe wiring; installation of a wire ID strap on the left-and right-hand sides of each terminal block; and installation of a warning placard. This amendment is prompted by a report of severe flight control buffeting of a Learjet Model 55 series airplane due to a malfunction of the horizontal stabilizer anti-ice system. The actions specified by this AD are intended to prevent undetected accretion of ice on the leading edge of the horizontal stabilizer, which could result in the loss of pitch control and consequent reduced controllability of the airplane.
Which aircraft AD 99-19297 applies to
Whether AD 99-19297 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.