Airworthiness Directive 2008-17-12
one-timeAirworthiness Directives; Airbus Model A318, A319, A320, and A321 Series Airplanes Equipped With Certain Northrop Grumman (Formerly Litton) Air Data Inertial Reference Units
What this AD requires
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Airbus Model A319, A320, and A321 series airplanes equipped with certain Litton air data inertial reference units (ADIRUs). That AD currently requires modifying the shelf (floor panel) above ADIRU 3, modifying the polycarbonate guard that covers the ADIRUs for certain airplanes, and modifying the ladder located in the avionics compartment for certain airplanes. This new AD requires those modifications on additional airplanes. This new AD also requires replacing all three ADIRUs with improved ADIRUs. This new AD also adds Model A318 series airplanes to the applicability. This AD results from reports that "NAV IR FAULT" messages have occurred during takeoff due to failure of an ADIRU and subsequent analysis showing that the shelf modification has not sufficiently addressed failure of an ADIRU. We are issuing this AD to prevent failure of an ADIRU during flight, which could result in loss of one source of critical attitude and airspeed data and reduce the ability of the flightcrew to control the airplane.
Which aircraft AD 2008-17-12 applies to
Applies to airplanes equipped with at least one Northrop Grumman (formerly Litton) air data inertial reference unit (ADIRU) of the listed part numbers; excludes airplanes equipped with three ADIRUs P/N 465020-0303 through -0316 on which Airbus Modification 30650 or 30872 has been incorporated in production, or on which Airbus SB A320-25-1248 has been applied in service.
Whether AD 2008-17-12 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.