22 Airworthiness Directives: 11 airplane, 3 rotorcraft, 5 engine, 1 propeller, 2 glider.
AD 99-08-02 R1 · published Jul 7, 1999, effective May 11, 1999
Boeing Model 747 Series Airplanes
This amendment corrects and clarifies an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires a one-time inspection to detect discrepancies of the center fuel tank wiring and components, and corrective action, if necessary; and a one-time electrical bonding test of the center fuel tank components, and rework, if necessary. For certain airplanes, the existing AD also requires a one-time insulation resistance test and a one-time inspection to detect discrepancies of the wiring and components of the fuel quantity indication system (FQIS), and corrective actions, if necessary; replacement of certain FQIS probes with certain newer probes; a system adjustment and system operational test; and modification (installation of a flame arrestor) of the inlet line of the scavenge pump of the center fuel tank. This amendment corrects an inadvertent omission to reference a specific section of the appropriate service information, and clarifies certain other requirements. This amendment is prompted by a comment received subsequent to issuance of the existing final rule, requesting clarification of certain requirements of the existing AD. The actions specified in this AD are intended to prevent ignition sources and consequent fire/explosion in the center fuel tank.
AD 99-14-07 · published Jul 7, 1999, effective Aug 11, 1999
Dassault Model 2000, 900EX, and Mystere Falcon 900 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all Dassault Model Falcon 2000 series airplanes; and certain Dassault Model 900EX, and Mystere Falcon 900 series airplanes, that requires repetitive operational tests of the flap asymmetry detection system to verify proper functioning, and repair, if necessary; repetitive replacement of the inboard flap jackscrews with new jackscrews; repetitive measurement of the screw/nut play to detect discrepancies; and corrective action, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent jamming of the flap jackscrews, which could result in the inability to move the flaps or an asymmetric flap condition, and consequent reduced controllability of the airplane.
AD 99-15-04 · published Jul 13, 1999, effective Aug 31, 1999
The New Piper Aircraft, Inc. Models PA- 46-310P and PA-46-350P Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to all The New Piper Aircraft, Inc. (Piper) Models PA-46-310P and PA-46-350P airplanes. This AD requires calibrating the turbine inlet temperature system to assure the accuracy of the existing turbine inlet temperature indicator and wiring for all of the applicable airplanes, and repairing or replacing any turbine inlet temperature system that fails the calibration test. This AD also requires repetitively replacing the turbine inlet temperature probe on the Model PA-46-350P airplanes, and inserting a copy of this AD into the Pilot's Operating Handbook of certain airplanes. This AD is the result of field reports that indicate service accuracy problems with the existing turbine inlet temperature system. The actions specified by this AD are intended to prevent improper engine operation caused by improperly calibrated turbine inlet temperature indicators or defective turbine inlet temperature probes, which could result in engine damage/failure with consequent loss of control of the airplane.
AD 99-15-05 · published Jul 14, 1999, effective Aug 18, 1999
The Boeing Company Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, that requires a one-time visual inspection to determine if all corners of the aft lower cargo doorjamb have been previously modified. This amendment also requires low frequency eddy current inspections to detect cracks of the fuselage skin and doubler at all corners of the aft lower cargo doorjamb, various follow-on repetitive inspections, and modification, if necessary. This amendment is prompted by fatigue cracks found in the fuselage skin and doubler at the corners of the aft lower cargo doorjamb. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.
AD 99-15-11 · published Jul 20, 1999, effective Sep 10, 1999
British Aerospace HP137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to all British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes. This AD requires repetitively removing the nose landing gear steering selector valve and installing either a new nose landing gear steering selector valve or one that has been overhauled in accordance with the appropriate component maintenance manual. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent the inability to steer the airplane because of wear in the nose landing gear steering selector differential, which could result in loss of control of the airplane during take-off, landing, or taxi operations.
AD 99-15-07 · published Jul 21, 1999, effective Sep 10, 1999
deHavilland Inc. Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to all deHavilland Inc. (deHavilland) Models DHC-2 Mk. I, DHC-2 Mk. II, and DHC-2 Mk. III airplanes. This AD requires repetitively inspecting the rear fuselage bulkhead at Station 228 for cracks. This AD also requires repairing any crack found or replacing any cracked rear fuselage bulkhead in accordance with a repair or replacement scheme obtained from the manufacturer through the Federal Aviation Administration (FAA). This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Canada. The actions specified by this AD are intended to detect and correct cracking of the rear fuselage bulkhead at Station 228, which could result in structural damage of the fuselage to the point of failure with consequent loss of airplane control.
AD 99-15-08 · published Jul 21, 1999, effective Aug 25, 1999
Boeing Model 747-200 and -300 Series Airplanes Equipped With General Electric CF6-80C2 Series Engines
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747-200 and -300 series airplanes, that currently requires various inspections and functional tests to detect discrepancies of the thrust reverser control and indication system, and correction of any discrepancy found. This amendment reduces the repetitive interval for one certain functional test. This amendment is prompted by reports indicating that several center drive units (CDU) were returned to the manufacturer of the CDU's because of low holding torque of the CDU cone brake. The actions specified by this AD are intended to ensure the integrity of the fail safe features of the thrust reverser system by preventing possible failure modes in the thrust reverser control system that can result in inadvertent deployment of a thrust reverser during flight.
AD 99-15-10 · published Jul 21, 1999, effective Aug 5, 1999
Boeing Model 777 Series Airplanes
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 777 series airplanes. This action requires replacement of a certain engine-driven pump (EDP) supply shutoff valve, which is located in the aft strut fairing, with a new shutoff valve. This amendment is prompted by reports of failure of the shutoff valve due to corrosion in the direct current motor in the shutoff valve. The actions specified in this AD are intended to prevent failure of an EDP supply shutoff valve. Such failure, in the event of an engine fire, could result in an uncontrolled fire in the engine compartment.
AD 99-15-12 · published Jul 22, 1999, effective Aug 6, 1999
Saab Model SAAB 2000 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 2000 series airplanes. This action requires repetitive detailed inspections to detect looseness or gap of the press fit bushing installation of the actuator fittings of the aileron trim tabs, and eventual replacement of the bushings with new, staked bushings. Accomplishment of such replacement terminates the repetitive inspections. This action also provides for an optional temporary preventive action, which, if accomplished, would terminate the repetitive inspections until the terminating action is accomplished. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent looseness or gap of the bushings. In the event of failure of the redundant trim tab actuator, such looseness or gap of the bushings could lead to trim tab flutter and consequent structural failure of the trim tab and reduced controllability of the airplane.
AD 99-15-09 · published Jul 27, 1999, effective Aug 11, 1999
Boeing Model 737-600 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-600 series airplanes. This action requires revising the Airplane Flight Manual (AFM) to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fittings of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. This AD also requires installing an additional fastener on the elevator tab mast fitting, which terminates the AFM revision and extends certain repetitive inspections. This AD also requires replacement of the elevator tab mast fitting with a new, improved fitting, which constitutes terminating action for the requirements of this AD. This amendment is prompted by a report of a severe vibration incident on a Boeing Model 737-800 series airplane; inspection revealed fracturing of the elevator tab mast fitting and excessive freeplay in the elevator tab. The actions specified in this AD are intended to prevent loss of controllability of the airplane due to excessive freeplay in the elevator tab or a free tab.
AD 99-16-01 · published Jul 28, 1999, effective Sep 1, 1999
Airbus Industrie Model A300-600 Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Airbus Industrie Model A300-600 series airplanes, that currently requires repetitive high frequency eddy current inspections to detect cracks in bolt holes where parts of the main landing gear are attached to the rear spar, and repair, if necessary. This amendment requires repetitive ultrasonic inspections to detect cracking in certain bolt holes of the rear spar, and repair, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to detect and correct cracking of the rear spar of the wing, which could result in reduced structural integrity of the airplane.
AD 99-12-01 · published Jul 1, 1999, effective Jul 16, 1999
Eurocopter Deutschland (Eurocopter) Model EC135 Helicopters
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-12-01, which was sent previously to all known U.S. owners and operators of Eurocopter Model EC135 helicopters by individual letters. This AD requires initial and repetitive visual inspections and one dye-penetrant inspection of the main rotor hub shaft (shaft) for cracks. If a crack is found during any of the inspections, this AD requires replacing the shaft with an airworthy shaft before further flight. This amendment is prompted by the discovery of fatigue cracks on the shaft of a helicopter. The actions specified by this AD are intended to detect fatigue cracks in the shaft that could lead to shaft failure and subsequent loss of control of the helicopter.
AD 99-13-09 · published Jul 20, 1999, effective Aug 4, 1999
MD Helicopters, Inc (MDHI) Model 369D and E Helicopters
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-13-09 which was sent previously to all known U.S. owners and operators of MDHI Model 369D and E helicopters by individual letters. This AD requires, prior to further flight, inspecting and replacing, if necessary, a certain four- bladed tail rotor fork (fork) assembly. This AD also requires a repetitive inspection of certain fork assemblies at intervals not to exceed 50 hours time-in-service (TIS) and removing and replacing, if necessary, each unairworthy fork assembly with an airworthy fork assembly before further flight. This amendment is prompted by reports from the manufacturer of the discovery of a discrepant part. The actions specified by this AD are intended to prevent failure of certain fork assemblies, which could cause loss of a tail rotor blade and subsequent loss of control of the helicopter.
AD 99-15-14 · published Jul 22, 1999, effective Aug 26, 1999
Sikorsky Aircraft-Manufactured Model CH-54B Helicopters
This amendment adopts a new airworthiness directive (AD), applicable to Sikorsky Aircraft-manufactured Model CH-54B helicopters, that requires initial and recurring inspections and rework or replacement, if necessary, of the second stage lower planetary plate (plate). This amendment is prompted by two reports of cracked plates that have been found during overhaul and inspections. The actions specified by this AD are intended to prevent failure of the main gearbox plate due to fatigue cracking, which could lead to failure of the main gearbox and subsequent loss of control of the helicopter.
AD 99-14-08 · published Jul 13, 1999, effective Sep 13, 1999
Pratt & Whitney JT9D Series Turbofan Engines
This amendment supersedes an existing airworthiness directive (AD), applicable to Pratt & Whitney (PW) JT9D series turbofan engines, that currently requires initial and repetitive inspections of the sixth stage low pressure turbine (LPT) inner airseal, and modification of the sixth stage LPT inner airseal to reduce the potential for two failure modes. This amendment requires additional repetitive borescope inspections for sixth stage LPT inner airseals found with cracks less than one inch in length. This amendment is prompted by the publication of a revision to a PW service bulletin that introduces the new borescope inspections. The actions specified by this AD are intended to prevent an uncontained failure of the sixth stage LPT inner airseal, which can result in damage to the aircraft.
AD 99-15-01 · published Jul 16, 1999, effective Sep 14, 1999
Pratt & Whitney PW4000 Series Turbofan Engines
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.
AD 99-15-02 · published Jul 16, 1999, effective Aug 16, 1999
Pratt & Whitney JT9D Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines, that requires initial and repetitive in-shop eddy current and on-wing ultrasonic inspections of the Combustion Chamber Outer Casing (CCOC) forward flange (L-flange) fillet radius for cracking, and replacing cracked L-flanges with serviceable parts. Replacement with an improved L-flange constitutes terminating action to the repetitive inspections. This amendment is prompted by reports of CCOC rupture due to cracking in the L-flange fillet radius. The actions specified by the proposed AD are intended to prevent CCOC rupture due to cracking, which could result in an uncontained engine failure and damage to the aircraft.
AD 99-15-06 · published Jul 19, 1999, effective Sep 17, 1999
AlliedSignal Inc. (Formerly Textron Lycoming) Model ALF502R-5 and ALF502R-3A Turborfan Engines
This amendment adopts a new airworthiness directive (AD), applicable to AlliedSignal Inc. Model ALF502R-5 and ALF502R-3A turbofan engines, that requires incorporation of an improved fan core inlet anti-ice system. This amendment is prompted by reports of uncommanded reduction of engine thrust (rollback) and loss of thrust control in icing conditions. The actions specified by this AD are intended to prevent ice accretion on the fan core inlet stator vane surfaces, which can result in engine rollback and loss of thrust control in icing conditions.
AD 98-23-07 R1 · published Jul 30, 1999, effective Jul 30, 1999
Pratt & Whitney JT9D Series Turbofan Engines
This amendment rescinds Airworthiness Directive (AD) 98-23-07, which is applicable to certain Pratt & Whitney (PW) JT9D series turbofan engines. That AD requires a one-time acid etch inspection of the turbine exhaust case (TEC) wall between and on either side of the ``3R'' and ``S'' rails in the engine mount lug area (top quadrant of the case) for the presence of weld material, and if weld material is detected, removal from service and replacement with serviceable parts. The requirements of that AD were intended to prevent TEC structural failure under abnormal operating conditions, which could result in reduced main mount load capability, engine separation from the wing and subsequent loss of control of the airplane. Since the issuance of that AD, the FAA received reports from the manufacturer that describe a new safety analysis that determines the acid etch inspection for weld material is unnecessary.
AD 99-14-06 · published Jul 8, 1999, effective Jul 23, 1999
MT-Propeller Entwicklung GMBH Models MTV-9-B-C and MTV-3-B-C Propellers
This amendment adopts a new airworthiness directive (AD) that is applicable to MT-Propeller Entwicklung GMBH Models MTV-9-B-C and MTV-3-B-C propellers. This action requires initial and repetitive inspections of Torx head blade root lag screws for torque values and breakage, and, if any screws are found broken or with insufficient torque, replacement of all screws with new lag screws. In addition, this AD requires replacement of certain model Torx head blade root lag screws with improved, hexagonal head blade root lag screws. This amendment is prompted by reports of broken Torx head blade root lag screws. The actions specified in this AD are intended to prevent blade root lag screw breakage, which could result in propeller blade separation and loss of control of the airplane.
AD 99-15-03 · published Jul 14, 1999, effective Aug 31, 1999
Stemme GmbH & Co. KG Model S10-VT Sailplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Stemme GmbH & Co. KG (Stemme) Model S10-VT sailplanes. This AD requires modifying the wastegate control in order to eliminate heat damage. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified by this AD are intended to prevent the wastegate control from malfunctioning because of heat damage, which could result in loss of automatic manifold pressure control and engine damage.
AD 99-15-13 · published Jul 26, 1999, effective Sep 13, 1999
Alexander Schleicher Segelflugzeugbau Model ASH 26E Sailplanes
This amendment supersedes Airworthiness Directive (AD) 98-09- 09, which currently requires replacing the internal cooling air fan with a fan that incorporates a white impeller on all Alexander Schleicher Segelflugzeugbau (Alexander Schleicher) Model ASH 26E sailplanes. This AD requires inspecting the internal cooling air fan for damage, and replacing any fan that does not incorporate a black impeller with a fan that incorporates a black impeller either immediately or at a certain time period, depending on the results of the inspection. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified by this AD are intended to prevent failure of the internal cooling system air fan caused by a certain design configuration of the impeller, which could cause the engine to overheat with possible engine failure.
