Is AD 99-15-01 a recurring Airworthiness Directive?

No — AD 99-15-01 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 99-15-01 apply to?

AD 99-15-01 applies to Pratt & Whitney — models PW4056, PW4152, PW4156A, PW4164, PW4168, PW4460, PW4000. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-15-01

one-time

Official AD 99-15-01 · FR doc 99-17554 · 1999-07-16 · turbine engine

Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD), applicable to certain Pratt & Whitney PW4000 series turbofan engines, that reduces life limits of certain 4th stage low pressure turbine (LPT) disks. It also allows the original life limits of the disks to be restored if reoperation is performed to incorporate the original slotted cooling hole configuration. This amendment is prompted by reports that a change of a cooling hole geometry, which was introduced in the design of certain 4th stage LPT disks, inadvertently caused a reduction on the cooling air flow to the disk and an increased level of stress. The actions specified by this AD are intended to prevent an uncontained disk failure and damage to the aircraft.

Which aircraft AD 99-15-01 applies to

MakesPratt & Whitney

ModelsPW4056, PW4152, PW4156A, PW4164, PW4168, PW4460, PW4000

Part-conditional — 50N924.

Applies only to engines with 4th stage low pressure turbine (LPT) disk, P/N 50N924, S/Ns CLDL BX2061, CLDL BX6620, CLDL BX2054, CLDL BX2055, CLDL BX6596, CLDL BX2059, CLDL BX2060, CLDL BX6600, CLDL BX6597, CLDL BX6599, CLDL BX6601, CLDL BX6598, CLDL BX6604, CLDL BX6605, CLDL BX6602, CLDL BX6609, CLDL BX6607, CLDL BX6612, CLDL BX6611, CLDL BX6610, CLDL BX6608, CLDL BX6606, CLDL BX6615, CLDL BX6616, CLDL BX6619, CLDL BX2058, and CLDL BX6603 installed. Installed on but not limited to Airbus Industrie A330, Boeing 747, and McDonnell Douglas MD-11 series aircraft.

Whether AD 99-15-01 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:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.

Date — When the work was done.

Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.

Signature & certificate — The A&P/IA who returned it to service, with certificate number.

Is AD 99-15-01 complied with on your aircraft?

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.