Airworthiness Directive 99-24-07
one-timeAirworthiness Directives; Boeing Model 757 Series Airplanes Equipped With Rolls Royce Engines
What this AD requires
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757 series airplanes equipped with Rolls Royce RB211 engines, that requires modification of the nacelle strut and wing structure. This amendment is prompted by reports indicating that the actual operational loads applied to the nacelle are higher than the analytical loads that were used during the initial design. Such an increase in loading can lead to fatigue cracking in primary strut structure prior to an airplane's reaching its design service objective. The actions specified by this AD are intended to prevent fatigue cracking in primary strut structure and consequent reduced structural integrity of the strut.
Which aircraft AD 99-24-07 applies to
Applies to Boeing 757 airplanes identified in the (truncated) preceding applicability provision. Requires modifying the nacelle strut and wing structure per Boeing SB 757-54-0035 (dated July 17, 1997) by the later of 37,500 total flight cycles/20 years since manufacture, or 3,000 flight cycles after this AD's effective date; terminating actions from the SB's 'Strut Improvement Bulletins' table (Table I) must be accomplished prior to or concurrently.
Whether AD 99-24-07 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.