Is AD 99-23-24 a recurring Airworthiness Directive?

No — AD 99-23-24 is a one-time directive. Verify it was complied with in the aircraft's records.

Which aircraft does AD 99-23-24 apply to?

AD 99-23-24 applies to Alliedsignal, Bendix/King — models RIA-32A. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-23-24

one-time

Official AD 99-23-24 · FR doc 99-29739 · 1999-11-19 · appliance

Airworthiness Directives; AlliedSignal, Instrument Landing System Navigation Receivers, as Installed in, but Not Limited to, Airbus Model A300 Series Airplanes and Boeing Model 747-100, -100B, -100B SUD, - 200B, -200F, -200C, -300, 747SR, and 747SP Series Airplanes

What this AD requires

This amendment adopts a new airworthiness directive (AD), applicable to certain instrument landing system (ILS) navigation receivers manufactured by AlliedSignal. This action requires replacement of certain resistors in the ILS navigation receiver with higher ohm resistors and replacement of the nameplate on the receiver with a new nameplate. This amendment is prompted by reports of ILS navigation receivers incorrectly indicating signals from the glideslope ground station during final approach. The actions specified in this AD are intended to ensure the ILS receiver provides the flight crew with accurate glideslope data. Inaccurate glideslope data could result in an approach off the glideslope, and, consequently, a landing short of the runway or a runway overrun.

Which aircraft AD 99-23-24 applies to

MakesAlliedsignalBendix/King

ModelsRIA-32A

Serial-conditional — narrows to serials 1–2365, 2366–?.

Part-conditional — 2070724-3201, 2070724-3203.

Applies to AlliedSignal RIA-32A ILS navigation receivers having P/N 2070724-3201 and -3203, as installed on any airplane, regardless of airframe modification/alteration/repair. Units with serial numbers 1-2365 require resistor replacement (Bendix/King SB RIA-32A-34-47 Rev 1) plus nameplate replacement (SB RIA-32A-34-48); units with serial number 2366 and subsequent require only the nameplate replacement.

Whether AD 99-23-24 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 99-23-24 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.