42 Airworthiness Directives: 31 airplane, 3 rotorcraft, 5 engine, 1 propeller, 2 glider.
AD 99-18-04 · published Sep 1, 1999, effective Oct 6, 1999
Dornier Model 328-100 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes, that requires repetitive inspections to detect cracking of the support beam of the main landing gear (MLG) fairing, and a permanent repair, if necessary. This AD also requires installation of reinforcement parts for the longitudinal beam of the MLG fairing, which terminates the requirements of this AD. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent cracking of the support beam of the MLG fairing, which could result in reduced structural integrity of the lower part of the MLG fairing, and consequent separation of part of the fairing from the airplane and possible damage to the airplane or injury to persons on the ground.
AD 99-18-11 · published Sep 1, 1999, effective Oct 6, 1999
Short Brothers Model SD3-SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all Short Brothers Model SD3-SHERPA, SD3-60 SHERPA, SD3- 30, and SD3-60 series airplanes, that requires replacement of the existing bolts that secure the elevator control torque tube bearing housing retaining plate with hex head bolts. 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 reduced movement of the elevator controls and consequent reduced controllability of the airplane, as a result of bolts coming loose on the elevator control torque tube bearing housing retaining plate.
AD 99-18-14 · published Sep 1, 1999, effective Sep 27, 1999
Cessna Aircraft Company Model 172R Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to Cessna Aircraft Company (Cessna) Model 172R airplanes equipped with a certain modification kit that reduces friction in the elevator control system. This AD requires inspecting the control yoke pivot bolt to assure positive clearance between the pivot bolt's threaded end and aileron direct cable. If positive clearance is not found, this AD requires replacing the control yoke pivot bolt, inspecting the adjacent aileron control cables for damage, and replacing any damaged aileron control cable. This AD is the result of the manufacturer supplying incorrect length control yoke pivot bolts in Cessna Modification Kits MK 172-27-01 that were shipped from September 21, 1998, through April 18, 1999. The actions specified by this AD are intended to prevent failure of an aileron control cable because of an incorrect length control yoke pivot bolt rubbing on one of these cables, which could result in loss of aileron control with loss of directional control of the airplane.
AD 99-18-16 · published Sep 1, 1999, effective Sep 16, 1999
Boeing Model 747-400, 757-200, 767-200, and 767-300 Series Airplanes
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400, 757-200, 767-200, and 767-300 series airplanes. This action requires repetitive checks to detect certain failures in the warning electronic unit (WEU) or modular avionic warning electronic assembly (MAWEA); repetitive tests to detect any failure of tactile, visual, or aural alert generated by the WEU or MAWEA; and corrective action, if necessary. This AD also provides for an optional terminating action for the repetitive checks and tests. This amendment is prompted by a report of a MAWEA power supply failure due to inadequate over-voltage protection. The actions specified in this AD are intended to detect and correct such a failure, which could result in loss of visual, aural, and tactile alerts to the flightcrew. Absence of such alerts could result in the flightcrew being unaware that an immediate or appropriate action should be taken in the event of an unsafe condition.
AD 99-18-19 · published Sep 3, 1999, effective Sep 24, 1999
General Electric Company CF6-80A1/A3 and CF6-80C2A Series Turbofan Engines, Installed on Airbus Industrie A300-600 and A310 Series Airplanes
This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company CF6-80A1/A3 and CF6-80C2A series turbofan engines, installed on Airbus Industrie A300-600 and A310 series airplanes. This action requires, prior to further flight, one of the following: performing a DPV pressure check for leakage, and, if necessary, replacing the DPV assembly with a serviceable assembly and performing an operational check of the thrust reverser, or deactivating the thrust reverser; or replacing the directional pilot valve (DPV) assembly with a serviceable assembly and performing an operational check of the thrust reverser. Thereafter, this AD requires one of these actions on a repetitive basis. If a thrust reverser is deactivated, this action requires, prior to further flight, revising the FAA-approved airplane flight manual (AFM) to require performance penalties to be applied for certain takeoff conditions. The AD also requires a revision to the Emergency Procedures Section of the FAA approved AFM to include a flightcrew operational procedure in the event of any indication of an in-flight thrust reverser deployment. This amendment is prompted by review of thrust reverser safety analyses following a report of inadvertent thrust reverser deployment on another make and model engine. The actions specified in this AD are intended to prevent inadvertent thrust reverser deployment, which, if it occurred in-flight, could result in loss of control of the airplane.
AD 99-18-21 · published Sep 3, 1999, effective Oct 8, 1999
Dornier Model 328-100 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes, that requires a one-time inspection of the propeller de-ice system to verify the proper functioning of the engine indication and crew alert system (EICAS) for the de-ice system; 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 failure of the EICAS to provide a warning to the flightcrew in the event of failure of the propeller de-ice system, which could result in damage to the airplane and consequent loss of controllability of the airplane.
AD 99-18-22 · published Sep 3, 1999, effective Oct 8, 1999
Fokker Model F27 Series Airplanes Equipped With Rolls-Royce 532-7 ``Dart 7'' (RDa-7) Series Engines
This amendment adopts a new airworthiness directive (AD), applicable to certain Fokker Model F27 series airplanes, that requires revising the Airplane Flight Manual (AFM) to provide the flightcrew with modified operational procedures to ensure continuous operation with the high pressure cock (HPC) levers in the lockout position. 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 burnout of the engines during flight by ensuring that the HPC levers are in a permanent lockout position.
AD 99-18-23 · published Sep 3, 1999, effective Oct 8, 1999
McDonnell Douglas Model MD-90-30 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all McDonnell Douglas MD-90-30 series airplanes, that requires revising the Airworthiness Limitations Section of the Instructions for Continued Airworthiness [MD-90-30 Airworthiness Limitations Instructions (ALI)] to incorporate certain replacement times for safe-life limited parts. This amendment is prompted by analysis of data that identified reduced replacement times for certain safe-life limited parts. The actions specified by this AD are intended to prevent fatigue cracking of various safe-life limited parts; such fatigue cracking could adversely affect the structural integrity of these airplanes.
AD 99-19-21 · published Sep 15, 1999, effective Oct 20, 1999
Saab Model SAAB SF340A and SAAB 340B Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that requires repetitive inspections to detect cracking around certain fastener holes and adjacent areas of the front spar of the horizontal stabilizers; and corrective actions, if necessary. This amendment also requires repetitive x-ray inspections, cold working of certain fastener holes of the front spar of the horizontal stabilizers, and follow-on actions; and installation of new fasteners, which constitutes terminating action for the repetitive inspections required by this AD. This amendment is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the front spar due to fatigue cracking around certain fastener holes of the front spar of the horizontal stabilizers, which could result in reduced structural integrity of the airplane.
AD 99-19-24 · published Sep 15, 1999, effective Oct 20, 1999
Dassault Model Mystere-Falcon 900, Falcon 900EX, and Falcon 2000 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Dassault Model Mystere-Falcon 900, Falcon 900EX, and Falcon 2000 series airplanes, that requires replacement of the elevator auxiliary artificial feel unit (AFU) with a new elevator auxiliary AFU. 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 failure of the elevator auxiliary AFU. Failure of an AFU, coupled with a control linkage disconnection upstream of the servo actuator and downstream of the main AFU, could result in reduced controllability of the airplane.
AD 99-19-25 · published Sep 15, 1999, effective Sep 30, 1999
Airbus Model A340 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A340 series airplanes. This action requires a one-time inspection of all gland nuts supplied with certain shock struts of the center landing gear (CLG) to verify that the gland nuts have the correct thread profile, and replacement of any defective gland nut with a new gland nut. 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 the failure of the CLG, and subsequent damage to the airplane structure or injury to airplane occupants.
AD 99-19-26 · published Sep 15, 1999, effective Oct 20, 1999
Airbus Model A300 and A300-600 Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Airbus Model A300 and A300-600 series airplanes, that currently requires inspections to detect cracks in Gear Rib 5 of the main landing gear (MLG) attachment fittings at the lower flange, and repair, if necessary. This amendment establishes repetitive inspection intervals for certain inspections required by the existing AD. This amendment also adds a requirement to modify Gear Rib 5 of the MLG attachment fittings, which constitutes terminating action for the repetitive inspections. 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 fatigue cracking of the MLG attachment fittings, which could result in reduced structural integrity of the airplane.
AD 99-19-27 · published Sep 15, 1999, effective Oct 20, 1999
Boeing Model 737-100, -200, -300, -400, and -500 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, that requires a one-time inspection of the main landing gear (MLG) wheel assemblies to determine whether certain parts are installed, and follow-on corrective actions, if necessary. For certain airplanes, this amendment also requires eventual modification of MLG wheel assemblies, which terminates the requirements of this AD. This amendment is prompted by incidents of multiple tie bolt failures on certain BFGoodrich wheel assemblies. The actions specified by this AD are intended to prevent failure of multiple tie bolts of MLG wheel assemblies, which could result in failure of the wheel rim, rapid release of tire pressure, and possible consequent damage to the airplane and injury to passengers and flightcrew.
AD 99-19-28 · published Sep 15, 1999, effective Oct 20, 1999
Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120RT and -120ER Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain EMBRAER Model EMB-120RT and -120ER series airplanes, that requires repetitive detailed visual inspections to detect discrepancies of the brake assemblies on the main landing gear (MLG), and replacement of the brake assemblies with new or serviceable brake assemblies, if necessary. This amendment is prompted by reports of fatigue cracking or splitting of the brake stator disk at the thermal expansion slots. The actions specified by this AD are intended to prevent failure of the brake assemblies of the MLG due to cracking or splitting of the stator disk, which could result in loss of brake effectiveness and could cause the airplane to leave the runway surface.
AD 99-19-29 · published Sep 15, 1999, effective Oct 20, 1999
Boeing Model 767 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires repetitive inspections of certain H-11 tension bolts at each side-of- body kick-load fitting and on the lower splice plate (both located on the wing rear spar) to detect damaged or broken bolts; and follow-on actions, if necessary. This amendment also requires eventual replacement of the existing bolts with new, improved bolts, which constitutes terminating action for the repetitive inspections. This amendment is prompted by a report that an operator found two broken H- 11 tension bolts on the side-of-body kick-load fitting on one airplane. The actions specified by this AD are intended to prevent cracking of the bolts due to stress corrosion, which could result in reduced structural integrity of the wing-to-body joint structure.
AD 99-19-32 · published Sep 17, 1999, effective Nov 8, 1999
Pilatus Aircraft Ltd. Models PC-12 and PC-12/45 Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC- 12/45 airplanes. This AD requires inspecting all flap actuator internal gear systems to assure that correct end-play and backlash measurements exist, and accomplishing any corrective adjustments as necessary. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. The actions specified by this AD are intended to prevent premature wear of the internal gear system caused by excessive backlash in the flight control flap actuators, which could eventually result in loss of actuator output with possible reduced or loss of airplane control.
AD 99-19-31 · published Sep 20, 1999, effective Oct 5, 1999
Airbus Model A340 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A340 series airplanes. This action requires repetitive inspections to detect cracking of the right inboard attachment lug of the main fitting of the center landing gear (CLG), and replacement with a new or serviceable CLG, if necessary. This action also provides for replacement of the CLG with an improved CLG as an optional terminating action for the repetitive inspections. 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 detect and correct cracks in the attachment lug, which could result in failure of the CLG.
AD 99-19-34 · published Sep 22, 1999, effective Oct 27, 1999
Bombardier Model DHC-8-100 and -300 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100 and -300 series airplanes, that requires modification of certain hydraulic systems that provide hydraulic pressure for the control of the rudder and for the main landing gear brakes. 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 damage to certain hydraulic system components in the number 2 engine nacelle, which could result in loss of the number 1 and number 2 hydraulic systems, and consequent reduced controllability of the airplane.
AD 99-19-35 · published Sep 22, 1999, effective Oct 27, 1999
British Aerospace BAe Model ATP Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace BAe Model ATP airplanes, that requires repetitive tests for the serviceability of the nose landing gear compensator; 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 a nose wheel shimmy, which could lead to the collapse of the nose landing gear during landing.
AD 99-19-36 · published Sep 22, 1999, effective Oct 27, 1999
Dornier Model 328-100 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Dornier Model 328-100 series airplanes, that requires a one-time inspection to measure the offset of the de-icing tubing adjacent to the refueling panel on the right-hand wing, and replacement with new improved tubing, 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 a blockage in the de-icing tubing which could result in a malfunction of the de-icing boot. This malfunction would be unknown to the flight crew, and could lead to reduced controllability of the airplane during flight in icing conditions.
AD 99-19-37 · published Sep 22, 1999, effective Oct 27, 1999
Bombardier Model DHC-8-100 and -300 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100 and -300 series airplanes, that requires replacement of the main landing gear (MLG) uplock actuator on both the left and right MLG with a new redesigned uplock assembly. 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 failure of the MLG to extend when a ``gear down'' selection is made.
AD 99-19-38 · published Sep 22, 1999, effective Oct 27, 1999
Airbus Model A310 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A310 series airplanes, that requires repetitive high frequency eddy current inspections to detect fatigue cracking at the hole in the lower web of the inner and outer attachment fittings of the number 3 wing spoilers; and corrective actions, if necessary. This amendment also provides for an optional modification, which terminates the repetitive inspections. 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 fatigue cracking and eventual failure of the attachment fittings of the number 3 wing spoilers.
AD 99-19-39 · published Sep 22, 1999, effective Oct 27, 1999
Bombardier Model CL-600-2B19 (Regional Jet Series 100) Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) series airplanes, that requires removal of the insulation blankets surrounding the emergency overwing exit hatches. 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 the freezing of moisture entrapped in the fiberglass/foam insulation installed on the fuselage structure between the overwing exit door and the fuselage door frame and intercostal, which could interfere with the opening of the overwing emergency exit hatches during an emergency evacuation of the airplane.
AD 99-19-40 · published Sep 22, 1999, effective Oct 27, 1999
Airbus Model A310 and A300-600 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A310 and A300-600 series airplanes, that requires a detailed visual inspection to detect damage to the terminal lugs on the 12XC and 15XE connectors and the mounting lugs on the 15XE connector; and repair or replacement of the terminal lugs or the 15XE connector with new parts, if necessary. This amendment is prompted by the issuance of a mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to detect and correct broken terminal and mounting lugs on the 15XE and 12XC connectors in the 101VU panel in the avionics compartment, which could result in loss of electrical power from the standby generator.
AD 99-19-41 · published Sep 22, 1999, effective Oct 27, 1999
Saab Model SAAB SF340A and SAAB 340B Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes, that requires modification of the insulation pads in the lower side of the fuselage at the wing aft area. 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 loose insulation from interfering with an aileron control cable, which could result in reduced aileron control.
AD 99-20-01 · published Sep 22, 1999, effective Oct 27, 1999
Fokker Model F.28 Mark 0070 and 0100 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all Fokker Model F.28 Mark 0070 and 0100 series airplanes, that requires modification of the electrical wiring of the flight warning computer (FWC), and installation of upgraded computer software into the FWC. 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 certain nuisance alerts generated by the FWC and to ensure annunciation of certain flight alerts by the FWC during initial climb. Such nuisance alerts or failures to annunciate certain alerts could result in an improper response by the flight crew and consequent reduced controllability of the airplane.
AD 99-20-02 · published Sep 22, 1999, effective Oct 27, 1999
Fokker Model F.28 Mark 0070 and 0100 Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to all Fokker Model F.28 Mark 0070 and 0100 series airplanes, that currently requires Airplane Flight Manual (AFM) and maintenance program revisions, modifications, and repetitive checks associated with ensuring the integrity of the thrust reverser system. This amendment continues to require the modifications and repetitive checks, and adds an AFM revision, repetitive operational tests, and other modifications related to the thrust reverser system. The new modifications terminate the repetitive operational checks and tests. This amendment is prompted by results of a review, which indicated that a potential latent failure of the secondary lock actuator switch 1 of the thrust reverser system in the open position may occur, in addition to the potential failure of the secondary lock relay 1 in the energized position. The actions specified by this AD are intended to ensure protection against inadvertent deployment of the thrust reversers during flight, which could result in reduced controllability of the airplane.
AD 99-20-05 · published Sep 24, 1999, effective Oct 29, 1999
Airbus Model A319, A320, and A321 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that requires modification of the 90VU electronics rack umbrellas, the 91VU upper shelf assembly, the cockpit drain circuit, and the electrical wire routing above the 90VU electronics rack. 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 damage to computer electrical connectors due to ingress of water into the avionics bay, which could result in malfunctioning of the avionics computers.
AD 99-20-06 · published Sep 24, 1999, effective Oct 29, 1999
Airbus Industrie Model A320 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Industrie Model A320 series airplanes, that requires replacement of the disc valve and spring in the low pressure non-return valve of the airborne ground check module (AGCM) of the ram air turbine (RAT). 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 malfunction of the low pressure non-return valve in the AGCM. If the RAT is being used due to the loss of other systems, a malfunction of the valve could result in loss of the blue hydraulic system, and consequent loss of certain flight control and electrical systems of the airplane.
AD 99-20-07 · published Sep 28, 1999, effective Nov 2, 1999
Fokker Model F.28 Mark 0070 and Mark 0100 Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to all Fokker Model F.28 Mark 0070 and Mark 0100 series airplanes, that currently requires revising the Airplane Flight Manual to provide the flightcrew with instructions not to arm the liftdumper system prior to commanding the landing gear to extend. This amendment requires modification of the grounds of the shielding of the wheelspeed sensor wiring of the main landing gear (MLG) and installation of new electrical grounds for the wheelspeed sensor channel of the anti-skid control box of the MLG. 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 electromagnetic interference generated by electrical wiring that runs parallel to the wheelspeed sensor wiring, which could result in inadvertent deployment of the liftdumpers during approach for landing or reduced brake pressure during low speed taxiing, and consequent reduced controllability and performance of the airplane.
AD 99-20-08 · published Sep 28, 1999, effective Oct 13, 1999
McDonnell Douglas Model MD-11 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to all McDonnell Douglas Model MD-11 series airplanes. This action prohibits installation of a certain In-flight Entertainment Network system. This amendment is prompted by the results of a special certification review of the in-flight entertainment system installed on a Model MD-11 series airplane that was involved in a recent accident. The actions specified in this AD are intended to prevent possible confusion as the flightcrew performs their duties in response to a smoke/fumes emergency, which could impair their ability to correctly identify the source of the smoke/fumes and subsequently affect the continued safe flight and landing of the airplane.
AD 99-19-30 · published Sep 17, 1999, effective Oct 4, 1999
Sikorsky Aircraft Corp. Model S76A, B, and C Helicopters
This amendment adopts a new airworthiness directive (AD) applicable to Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters. This action requires conducting a visual inspection to detect disbonding of the attachment angle between the tail gearbox forward fairing (fairing) and the pylon and replacing or repairing the attachment angles as necessary. This amendment is prompted by incidents, two in flight and eight on the ground, of fairing bonding failures. The actions specified in this AD are intended to prevent separation of the fairing, damage to the tail rotor blades, and subsequent loss of control of the helicopter.
AD 99-17-17 · published Sep 22, 1999, effective Oct 7, 1999
Robinson Helicopter Company Model R44 Helicopters
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-17-17 which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (RHC) Model R44 helicopters by individual letters. This AD requires, prior to further flight, replacing certain yoke assemblies with airworthy yoke assemblies. This amendment is prompted by an incident in which, during cruise flight, the pilot heard a loud bang and no tail rotor effectiveness due to a cracked yoke assembly. RHC has identified the manufacturing lots associated with the failed yoke assembly. The actions specified by this AD are intended to prevent failure of the yoke assembly, which could result in loss of main and tail rotor drive and subsequent loss of control of the helicopter.
AD 99-20-12 · published Sep 30, 1999, effective Nov 4, 1999
MD Helicopters Inc. Model 369D, D369E, 369FF, 500N, and 600N Helicopters
This amendment adopts a new airworthiness directive (AD), applicable to MD Helicopters, Inc. Model 369D, 369E, 369FF, 500N, and 600 N helicopters, that requires replacing the oil cooler blower bracket (bracket). This amendment is prompted by three reports of cracked brackets. The actions specified by this AD are intended to prevent failure of a bracket, loss of cooling of engine oil and transmission oil, and subsequent forced landing.
AD 99-18-20 · published Sep 3, 1999, effective Nov 2, 1999
General Electric Company CF6-50, -80A1/ A3, and -80C2A Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to General Electric Company (GE) CF6-50, -80A1/A3, and - 80C2A series turbofan engines installed on Airbus A300 and A310 series airplanes, that requires initial and repetitive thrust reverser inspections and checks, and allows extended repetitive inspection intervals if an optional double p-seal configuration is installed. This amendment is prompted by the report of a higher than anticipated center drive unit (CDU) cone brake failure rate which reduces the overall thrust reverser system protection against inadvertent deployment. The actions specified by this AD are intended to prevent inadvertent in- flight thrust reverser deployment, which can result in loss of control of the airplane.
AD 99-19-01 · published Sep 15, 1999, effective Sep 30, 1999
Teledyne Continental Motors O-470, IO- 470, TSIO-470, IO-520, TSIO-520, LTSIO-520, GTSIO-520, IO-550, TSIO- 550, and TSIOL-550 Series Reciprocating Engines
This amendment adopts a new airworthiness directive (AD) that is applicable to Teledyne Continental Motors (TCM) O-470, IO-470, TSIO- 470, IO-520, TSIO-520, LTSIO-520, GTSIO-520, IO-550, TSIO-550, and TSIOL-550 series reciprocating engines. This action supersedes priority letter AD 99-09-17 that currently requires a one-time visual and ultrasonic (UT) inspection of the No. 2 and No. 5 crankshaft cheeks for cracks. All crankshafts found with a cracked cheek must be replaced with a serviceable crankshaft prior to further flight. This action adds to the applicability TCM GTSIO-520 series engines and additional engines, identified by serial numbers (S/Ns), of currently affected engine series; references a revised service bulletin that clarifies snap ring installation; increases to 500 hours time-in-service (TIS) the cutoff for engines that require a more immediate inspection; and corrects the contact telephone number for TCM. This amendment is prompted by inspection results from the current priority letter AD. The actions specified by this AD are intended to prevent crankshaft failure due to crankshaft cheek cracks, which could result in total engine power loss, in-flight engine failure, and possible forced landing.
AD 99-20-03 · published Sep 24, 1999, effective Nov 23, 1999
Pratt & Whitney PW2000 Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney (PW) PW2000 series turbofan engines, that requires initial and repetitive inspections of certain High Pressure Turbine (HPT) stage 1 and stage 2 disks utilizing an improved ultrasonic inspection method performed at an approved facility when the disk is exposed during a shop visit, and if a crack indicating a subsurface anomaly is found, removal from service and replacement with a serviceable part. This amendment is prompted by the results of a stage 1 HPT disk fracture investigation, which has identified a population of HPT stage 1 and 2 disks that may have subsurface anomalies formed during a forging process. The actions specified by this AD are intended to prevent HPT disk fracture, which could result in an uncontained engine failure, and damage to the aircraft.
AD 99-20-04 · published Sep 24, 1999, effective Oct 29, 1999
Pratt & Whitney JT9D-7R4 Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT9D-7R4 series turbofan engines, that requires an initial and repetitive inspections of certain High Pressure Turbine (HPT) stage 1 and stage 2 disks utilizing an improved ultrasonic inspection method performed at an approved facility when the disks are exposed during a shop visit, and if a crack indicating a subsurface anomaly is found, removal from service and replacement with a serviceable part. This amendment is prompted by the results of a stage 1 HPT disk fracture investigation which has identified a population of HPT stage 1 and 2 disks that may have subsurface anomalies formed during the forging process. The actions specified by this AD are intended to prevent an HPC disk fracture, which could result in an uncontained engine failure, damage to the airplane, and an in-flight engine shutdown.
AD 98-17-01 R1 · published Sep 29, 1999, effective Nov 29, 1999
AlliedSignal Inc. TFE731 Series Turbofan Engines
This amendment revises an existing airworthiness directive (AD), applicable to AlliedSignal Inc. TFE731 series turbofan engines, that currently requires installation of an improved flexible (flex) fuel tube. This amendment clarifies that installation of the improved flex fuel tube and that the use of a clamp on the original rigid fuel tube are optional for engines installed on Learjet 35, 36, and 55 series airplanes. This amendment is prompted by confusion from operators regarding the applicability of these Learjet engine installations. The actions specified by this AD are intended to prevent cracking of the fuel tube and the subsequent leakage of fuel on or around electrical components, which can cause an engine fire.
AD 99-18-18 · published Sep 1, 1999, effective Sep 16, 1999
Dowty Aerospace Propellers Model R381/ 6-123-F/5 Propellers
This amendment adopts a new airworthiness directive (AD) that is applicable to Dowty Aerospace Propellers Model R381/6-123-F/5 propellers. This action requires initial and repetitive visual and ultrasonic (UT) inspections of propeller blades for cracks across the camber face, and, if blades are found cracked, replacement with serviceable blades. This amendment is prompted by reports of a cracked composite propeller blade. The actions specified in this AD are intended to prevent propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control.
AD 99-19-33 · published Sep 17, 1999, effective Nov 8, 1999
LET Aeronautical Works Model L-13 ``Blanik'' Sailplanes
This amendment adopts a new airworthiness directive (AD) that applies to all LET Aeronautical Works (LET) Model L-13 ``Blanik'' sailplanes. This AD requires painting (using a contrasting color, i.e., red paint) the left hand elevator drive mechanism in order to not have the elevator drive bellcrank inadvertently installed backwards. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic. The actions specified by this AD are intended to prevent the elevator drive bellcrank from being installed backwards, which could result in an incorrect rigging of the elevator flight control with potential reduced or loss of control of the sailplane.
AD 99-20-11 · published Sep 29, 1999, effective Oct 21, 1999
Burkhart Grob Luft-Und Raumfahrt GmbH & CO KG Models G103 TWIN II and G103A TWIN II ACRO Sailplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Burkhart Grob Luft-Und Raumfahrt GmbH & CO KG (Grob) Models G103 TWIN II and G103A TWIN II ACRO sailplanes. This AD requires accomplishing preflight checks of the fastening (knurled) nut at the rear control stick for cracks, and replacing the nut with one made of stainless steel either immediately or at a certain time period depending on whether a crack(s) is found. The checks are no longer required after the knurled nut is replaced. 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 inability to use the rear control stick because of a cracked knurled nut, which could result in loss of control of the sailplane during flight instruction operations.
