98-11-01
FR doc 98-13060 · 63 FR 27195AD 98-11-01Published 1998-05-18Effective 1998-06-07
Supersedes 97-23-04
Supersedence is read from the Federal Register text of the newer AD — the FAA publishes no structured field for it — and names only ADs held in our index.
Requires replacing the fuel tank vent valves with modified fuel tank vent valves on certain Pilatus Aircraft Ltd.
Full official abstract
This amendment supersedes Airworthiness Directive (AD) 97-23- 04, which currently requires replacing the fuel tank vent valves with modified fuel tank vent valves on certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. This AD retains the fuel tank vent valves replacement required by AD 97-23-04, and requires drilling a 4.8 millimeter (0.1875 inch) hole in each fuel filler cap. This AD also requires inserting a temporary revision in the Pilot's Operating Handbook (POH) that specifies checking to assure that the fuel filler cap hole is clear of ice and foreign objects. This AD is the result of mandatory continued airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to prevent the fuel tank inward vent valve from freezing, which, if followed by a cold soak at altitude, could result in wing airfoil distortion and structural damage with consequent degradation of the airplane's handling qualities.