29 Airworthiness Directives: 19 airplane, 5 rotorcraft, 3 engine, 1 appliance, 1 glider.
AD 99-08-05 R1 · published Jun 3, 1999, effective May 12, 1999
McDonnell Douglas Model DC-9 and C-9 (Military) Series Airplanes
This amendment corrects information in an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes, that currently requires repetitive inspections to detect fatigue cracking of the fuselage frames and longerons 16R and 17R above the forward lower cargo door; repair, if necessary; and modification of the fuselage frames and longerons, if necessary, and follow-on repetitive inspections to detect fatigue cracking of the skin adjacent to the modification. That AD was prompted by numerous instances of fatigue cracking of the fuselage frames and longerons. The actions specified by that AD are intended to prevent fatigue cracking of the fuselage frames and longerons 16R and 17R, which could result in reduced structural integrity of the airplane. This amendment corrects an erroneous reference to a certain volume of the Supplemental Inspection Document.
AD 99-11-13 · published Jun 3, 1999, effective Jun 21, 1999
Cessna Aircraft Company Model 402C Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Cessna Aircraft Company (Cessna) Model 402C airplanes. This AD requires inspecting the forward, aft, and auxiliary wing spars for cracks; repairing any cracks found; and reporting the results of the inspection to the Federal Aviation Administration (FAA). This AD is the result of an accident of one of the affected airplanes where the right-hand wing failed just inboard of the nacelle at Wing Station (WS) 87. Investigation of this accident revealed fatigue cracking of the forward main spar that initiated at the edge of the front spar forward lower spar cap. The actions specified by this AD are intended to detect and correct any cracks in the forward, aft, and auxiliary wing spars, which could result in reduced or loss of control of the airplane.
AD 99-11-14 · published Jun 3, 1999, effective Jul 8, 1999
Boeing Model 767 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires detailed visual inspections to detect corrosion or chrome plating cracks on the fuse pins of the outboard support of the main landing gear (MLG) beam. This AD also would require either installation of the existing fuse pins and repetitive inspections; or installation of newer-type fuse pins, which constitutes terminating action for the repetitive inspections. This amendment is prompted by a report indicating that corrosion was found on a fuse pin in the outboard support of the MLG beam. The actions specified by this AD are intended to detect and correct such corrosion and cracking, which could result in the failure of a fuse pin and, consequently, lead to collapse of the MLG.
AD 99-11-15 · published Jun 3, 1999, effective Jul 8, 1999
Boeing Model 747 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires a one-time detailed visual inspection to detect improperly installed or frayed aileron cables, and a one-time detailed visual inspection to detect improper identification or location of the cable markers, and corrective actions, if necessary. This amendment is prompted by a report that an aileron cable failed, due to improper installation onto the wrong groove of an aileron cable drum. The actions specified by this AD are intended to detect and correct an improperly installed aileron cable; such installation could lead to the failure of the aileron cable, and consequent reduced lateral control capability of the airplane.
AD 99-12-07 · published Jun 11, 1999, effective Jul 23, 1999
Raytheon Aircraft Company Model 1900D Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Raytheon Aircraft Company (Raytheon) Model 1900D airplanes. This AD requires replacing the passenger oxygen container and mask assembly with an improved design passenger oxygen container and mask assembly. This AD is the result of an incident where a passenger had put on the oxygen mask and the lanyard pin did not automatically pull and initiate oxygen flow during a loss of airplane pressurization while in-flight. The actions specified by this AD are intended to prevent the above situation from occurring on other airplanes, which could result in passenger injury if the lanyard pin is not manually pulled in a timely manner.
AD 99-12-08 · published Jun 11, 1999, effective Jul 16, 1999
Boeing Model 737-200C Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 737-200C series airplanes, that currently requires a one-time external detailed visual inspection to detect cracks of the fuselage skin in the lower lobe cargo compartment; repetitive internal detailed visual inspections to detect cracks of the frames in the lower lobe cargo compartment; and repair of cracked parts. That AD also provides for an optional preventative modification that constitutes terminating action for the repetitive inspections. This amendment requires accomplishment of the previously optional terminating modification. This amendment is prompted by reports of cracking in the body frames between stringers 19 left and 25 left and at body stations 360 to 500B. The actions specified by this AD are intended to prevent opening or loss of the cargo door during flight, and consequent rapid decompression of the airplane.
AD 99-12-02 · published Jun 14, 1999, effective Jul 9, 1999
Raytheon Aircraft Company Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) Airplanes
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-12-02, which was sent previously to all known U.S. owners and operators of Raytheon Aircraft Corporation (Raytheon) Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes. This AD requires incorporating operating limitations that restrict operation of the airplanes to normal category operation and prohibit them from acrobatic and utility category operations; limit the flight load factor to 0 to 2.5 G; and limit the maximum airspeed to 175 miles per hour (mph) (152 knots). This AD resulted from a report of an in-flight separation of the right wing on a Raytheon Beech Model A45 (T-34A) airplane. The actions specified by this AD are intended to assure the operational safety of the above- referenced airplanes.
AD 99-12-05 · published Jun 14, 1999, effective Jul 23, 1999
The New Piper Aircraft, Inc. Models PA- 31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 airplanes. This AD requires installing access holes for the inspection of the elevator spar; inspecting the elevator ice protection boots for looseness and reinstalling or replacing the elevator ice protection boots if looseness is found. This AD also requires repetitively inspecting the elevator spars for cracks, and replacing the elevators or elevator spar assemblies with parts of improved design either at a certain time period or when cracks are found, whichever occurs first. This AD is the result of reports of cracks developing in the elevator spar inboard of the outboard hinge location on the affected airplanes. The actions specified by this AD are intended to prevent failure of the elevator spar caused by fatigue cracking, which could result in reduced airplane controllability.
AD 99-13-04 · published Jun 18, 1999, effective Jul 13, 1999
Cessna Aircraft Company Models 206H and T206H Airplanes
This amendment adopts a new airworthiness directive (AD) that applies to certain Cessna Aircraft Company (Cessna) Models 206H and T206H airplanes. This AD requires inspecting the left and right wing aileron control bellcrank stop bolts and lock nuts for flush and tight contact with the surface of the threaded boss on each end of the yoke assemblies, and accomplishing follow-on and corrective actions, as applicable. This AD is the result of an inspection on one of the affected airplanes that showed that the aileron control bellcrank stop bolt had partially backed out of the threaded boss. The actions specified by this AD are intended to detect and correct loose aileron control bellcrank stop bolts, which could result in restricted movement of the ailerons with possible partial or complete loss of aileron control.
AD 99-12-52 · published Jun 23, 1999, effective Jun 28, 1999
Boeing Model 727 Series Airplanes
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T99-12-52 that was sent previously to all known U.S. owners and operators of all Boeing Model 727 series airplanes by individual telegrams. This AD requires a boost pump dry bay inspection to detect leakage of fuel through an arced- through conduit, and corrective action, as necessary. This AD also requires repetitive detailed visual inspections of the in-tank fuel boost pump wiring to detect chafing of the wire insulation, evidence of electrical arcing, or arc-through of the conduit wall on Model 727 series airplanes, and applicable corrective action; and installation of sleeving over the in-tank fuel boost pump wires as a method to protect the wiring from chafing. This action is prompted by reports of severe wear of in-tank fuel boost pump wiring, and arc-through of the surrounding conduit on two Model 727 series airplanes. The actions specified by this AD are intended to prevent fuel tank explosion resulting from arc-through of the fuel boost pump wiring conduits.
AD 99-13-05 · published Jun 23, 1999, effective Jul 8, 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 repetitive inspections to detect cracking of the upper cutout and lower flange of the outboard support assembly of the flaperons on the wings; and corrective actions, if necessary. This amendment also provides an optional terminating action for the repetitive inspections. This amendment is prompted by results of flight testing conducted by the manufacturer indicating that high engine thrust conditions during takeoff cause excessive cyclic loads and could lead to fatigue cracking of the outboard support of the flaperon. The actions specified in this AD are intended to detect and correct such fatigue cracking, which could result in fracture of the flaperon support structure, loss of the flaperon, and consequent reduced controllability of the airplane.
AD 99-13-07 · published Jun 23, 1999, effective Jul 28, 1999
McDonnell Douglas Model DC-9-80 Series Airplanes, Model MD-88 Airplanes, and Model MD-90-30 Airplanes
This amendment adopts a new airworthiness directive (AD); applicable to certain McDonnell Douglas Model DC-9-80 series airplanes, Model MD-88 airplanes, and Model MD-90-30 airplanes; that requires repetitive inspections to detect cracking of the main landing gear (MLG) shock strut pistons, and replacement of a cracked piston with a new or serviceable part. This amendment is prompted by reports indicating that, while an airplane was positioned on the taxiway, the right MLG shock strut piston failed due to fatigue cracking. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in failure of the piston, and consequent damage to the airplane structure or injury to the passengers and flightcrew.
AD 99-13-08 · published Jun 23, 1999, effective Jul 28, 1999
Lockheed Model L-1011-385 Series Airplanes
This amendment supersedes an existing airworthiness directive (AD), applicable to all Lockheed Model L-1011-385 series airplanes, that currently requires inspections to detect cracking and other discrepancies of certain web-to-cap fasteners of the rear spar between inner wing stations 310 and 343, and of the web area around those fasteners; and various follow-on actions. That AD also provides for an optional modification, which, if accomplished, would defer the initiation of the inspections for a certain period of time. This amendment requires accomplishment of the previously optional modification. This amendment is prompted by an FAA determination that the optional terminating modification specified in the existing AD must be accomplished within a specified period of time to ensure an acceptable level of safety of the affected fleet. The actions specified by this AD are intended to prevent fatigue cracking in the web of the rear spar of the wing, which could result in failure of the rear spar of the wing and consequent fuel spillage.
AD 99-13-13 · published Jun 28, 1999, effective Aug 2, 1999
The Boeing Company Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9, DC-9-80, and C-9 (military) series airplanes; Model MD-88 airplanes; and Model MD-90 airplanes, that requires a one-time inspection of the forward attach pins of the outboard flight spoiler actuators to determine whether the pins are of correct length, and follow-on corrective actions. This amendment is prompted by a report that forward attach pins of incorrect length were found to be installed in the flight spoiler actuators on several in-service and in-production airplanes. The actions specified by this AD are intended to prevent failure of the piston of the flight spoiler actuator and consequent puncturing of the aft spar web, which could result in fuel leakage and reduced structural integrity of the wings.
AD 99-14-01 · published Jun 28, 1999, effective Aug 17, 1999
Piper Aircraft Inc. Airplanes
This amendment supersedes Airworthiness Directive (AD) 98-04-27, which currently requires incorporating certain icing information into the FAA-approved airplane flight manual (AFM) of The New Piper Aircraft, Inc. (Piper) PA-23, PA-30, PA-31, PA-34, PA-39, PA-40, and PA-42 series airplanes. The Federal Aviation Administration (FAA) inadvertently omitted Piper Models PA-31P, PA-31T, PA-31T1, PA-31T2, and PA-31P-350 airplanes from the Applicability section of AD 98-04-27. This AD retains the requirement of incorporating the icing information into the AFM for all airplanes affected by AD 98-04-27, and adds Piper Models PA-31P, PA-31T, PA-31T1, PA-31T2, and PA-31P-350 airplanes to the Applicability section of the AD. The actions specified by this AD are intended to minimize the potential hazards associated with operating these airplanes in severe icing conditions by providing more clearly defined procedures and limitations associated with such conditions.
AD 99-14-03 · published Jun 28, 1999, effective Aug 17, 1999
Pilatus Aircraft Limited Airplanes
This amendment supersedes Airworthiness Directive (AD) 98-13-08, which currently requires replacing and re-routing the power return cables on the starter generator and the generator 2 on certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. AD 98-13-08 also requires inserting a temporary revision to the pilot operating handbook (POH), and installing a placard near the standby magnetic compass. This AD retains the actions currently required by AD 98-13-08 on all airplanes affected by that AD, and requires replacing the temporary revision to the POH and the placard near the standby magnetic compass with an improved procedural POH revision and placard. This AD also requires the placard and the temporary revision to the POH for additional manufacturer serial number Models PC-12 and PC-12/45 airplanes; and requires accomplishing improved Standby Magnetic Compass Swing procedures and incorporating a temporary revision to the maintenance manual on all of theaffected airplanes. 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 directional deviation on the standby magnetic compass caused by modifications made to the airplane since manufacture, which could result in flight-path deviation during critical phases of flight. The incorporation by reference of Pilatus PC-12 Maintenance Manual Temporary Revision No. 34-03, dated July 16, 1998, as specified in Pilatus Service Bulletin No. 34-006, dated September 3, 1998, as listed in the regulations is approved by the Director of the Federal Register as of August 17, 1999. The incorporation by reference of Pilatus PC XII Service Bulletin No. 24-002, Rev. No. 1, dated September 20, 1996, as listed in the regulations was previously approved by the Director of Federal Register as of July 31, 1998 (63 FR 32975, July 17, 1998).
AD 99-14-04 · published Jun 29, 1999, effective Jul 14, 1999
Boeing Model 747-300 and -400 Series Airplanes
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-300 and -400 series airplanes. This action requires repetitive inspections of the E-42 satellite communications (SATCOM) rack and fuselage (supporting) structure to detect cracking in the area surrounding the fastener holes, and to detect broken and missing fasteners; and corrective actions, if necessary. This amendment is prompted by reports indicating that cracking and broken and/or missing fasteners were found on the E- 42 SATCOM equipment rack structure that attaches to the fuselage structure. The actions specified in this AD are intended to detect and repair cracking of the E-42 SATCOM rack and its supporting structure, which could result in the SATCOM equipment falling from the rack, loss of SATCOM capabilities, injury to passengers, and reduced controllability of the airplane.
AD 99-13-51 · published Jun 30, 1999, effective Jul 6, 1999
Boeing Model 737-700 and -800 Series Airplanes
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T99-13-51 that was sent previously to all known U.S. owners and operators of certain Boeing Model 737-700 and -800 series airplanes by individual telegrams. This AD requires revising the Airplane Flight Manual (AFM) to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fitting of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. This AD also provides for optional terminating action for certain repetitive inspections. This AD requires installing an additional fastener on the tab mast fitting, which terminates the AFM revision and extends certain repetitive inspections. This action 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 by this AD are intended to prevent reduced controllability of the airplane due to excessive freeplay in the elevator tab or a free tab.
AD 99-14-05 · published Jun 30, 1999, effective Aug 4, 1999
Boeing Model 777-200 Series Airplanes
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 777-200 series airplanes, that requires inspections to verify correct installation of certain fasteners located on the trailing edges of the horizontal and vertical stabilizer; replacement of the existing fasteners with new fasteners installed with wet sealant; and follow-on actions, if necessary. This amendment is prompted by reports indicating that, during manufacture of the horizontal and vertical stabilizers, certain fasteners attaching the aluminum ribs and brackets to the trailing edges on the empennage were not correctly installed with wet sealant. The actions specified by this AD are intended to prevent corrosion and possible cracking of those aluminum parts, which could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane.
AD 99-13-02 · published Jun 17, 1999, effective Jul 2, 1999
Eurocopter France Model AS 332C, L, L1, and L2 Helicopters
This amendment supersedes an existing priority letter airworthiness directive (AD), applicable to Eurocopter France Model AS 332C, L, L1, and L2 helicopters, that currently requires conducting a filter clogging warning test, and, if necessary, replacing a jammed valve with an airworthy valve. This amendment requires the same corrective actions required by the existing AD; however, the applicability is reduced to encompass only certain part-numbered fuel filters. This amendment is prompted by jammed fuel filter by-pass valves and new information that justifies a reduction in the applicability of the superseded priority letter AD. The actions specified by this AD are intended to prevent engine power loss due to fuel starvation, which could cause one or both engines to flameout and a subsequent forced landing.
AD 99-13-03 · published Jun 17, 1999, effective Jul 2, 1999
Bell Helicopter Textron Canada (BHTC) Model 206L-4 Helicopters
This amendment adopts a new airworthiness directive (AD) that is applicable to BHTC Model 206L-4 helicopters. This action requires a reduction in the retirement lives of certain collective idler links and collective levers, and re-identifying certain collective idler links and collective levers. This amendment is prompted by the discovery of two types of collective idler links and collective levers--manufactured from different materials--that are identified with the same part numbers but should have substantially different retirement lives. The actions specified in this AD are intended to prevent use of a collective idler link (link) or collective lever (lever) beyond its retirement life, which could lead to failure of the link or lever and subsequent loss of control of the helicopter.
AD 99-11-04 · published Jun 24, 1999, effective Jul 9, 1999
Sikorsky Aircraft Model S-76A Helicopters
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-11-04 which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Model S-76A helicopters by individual letters. This AD requires, before further flight, either revising the flight manual to show reduced single-engine rotorcraft performance or determining if an AC generator interlock system is installed. If an interlock system is installed, the flight manual revision is not required. This amendment is prompted by the discovery that Sikorsky Aircraft Model S-76A helicopters with Turbomeca Arriel 1S1 engines may fail to achieve the specified single- engine rotorcraft performance if an AC generator interlock system is not installed. The actions specified by this AD are intended to prevent the inability of the rotorcraft to achieve certain published one- engine-inoperative performance.
AD 99-13-11 · published Jun 24, 1999, effective Jul 29, 1999
Robinson Helicopter Company (Robinson) Model R44 Helicopters
This amendment adopts a new airworthiness directive (AD), applicable to Robinson Model R44 helicopters, that requires installing a shutoff clamp on the auxiliary fuel tank sump drain tube (drain tube) and a placard decal to alert operators as to the proper use of the auxiliary fuel tank drain. This amendment is prompted by a report of fuel leaking from a drain tube opening in the area of the horizontal and vertical firewalls. The actions specified by this AD are intended to prevent fuel leaks from the drain tube that could cause a fire and subsequent loss of control of the helicopter.
AD 99-13-12 · published Jun 24, 1999, effective Jul 9, 1999
Bell Helicopter Textron Canada Model 206L, 206L-1, 206L-3, and 206L-4 Helicopters
This amendment supersedes an existing priority letter airworthiness directive (AD), applicable to Bell Helicopter Textron Canada (BHTC) Model 206L, 206L-1, 206L-3, and 206L-4 helicopters, that currently requires visual inspections and visual checks at specified time intervals, and a fluorescent-penetrant inspection (FPI) for any cracks in the tailboom skins around the horizontal stabilizer openings. Inserting a copy of the priority letter AD into the Rotorcraft Flight Manual (RFM) is also required. This amendment revises the inspection procedures and specified time intervals mandated by the priority letter AD. This amendment is prompted by crack growth analysis that indicates the need to detect cracks before they propagate from underneath the horizontal stabilizer supports. The actions specified by this AD are intended to detect a crack in the tailboom skin that could result in separation of the tailboom from the helicopter and subsequent loss of control of the helicopter.
AD 99-12-03 · published Jun 8, 1999, effective Jul 8, 1999
Pratt & Whitney JT8D-1, -1A, -1B, -7, - 7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR series turbofan engines, that requires revisions to the engine manufacturer's Time Limits Section (TLS) of the JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR Turbofan Engines Manual to include enhanced inspection of selected critical life-limited parts at each piece-part exposure. This amendment will also require an air carrier's approved continuous airworthiness maintenance program to incorporate these inspection procedures. This amendment is prompted by a Federal Aviation Administration (FAA) study of in-service events involving uncontained failures of critical rotating engine parts that indicated the need for improved inspections. The improved inspections are needed to identify those critical rotating parts with conditions that if allowed to continue in service, could result in uncontained failures. The actions specified by this AD are intended to prevent critical life- limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.
AD 99-12-04 · published Jun 8, 1999, effective Jul 8, 1999
Pratt & Whitney JT8D-200 Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT8D-200 series turbofan engines, that requires revisions to the engine manufacturer's Time Limits Section (TLS) of the JT8D-200 Turbofan Engine Manual to include enhanced inspection of selected critical life-limited parts at each piece-part exposure. This amendment will also require an air carrier's approved continuous airworthiness maintenance program to incorporate these inspection procedures. This amendment is prompted by a Federal Aviation Administration (FAA) study of in-service events involving uncontained failures of critical rotating engine parts that indicated the need for improved inspections. The improved inspections are needed to identify those critical rotating parts with conditions that if allowed to continue in service, could result in uncontained failures. The actions specified by this AD are intended to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.
AD 99-13-01 · published Jun 15, 1999, effective Jun 25, 1999
International Aero Engines AG V2500-A1 and V2500-A5 Series Turbofan Engines
This amendment adopts a new airworthiness directive (AD) that is applicable to certain International Aero Engines AG (IAE) V2500-A1 and V2500-A5 series turbofan engines. This action requires determining the need for a special borescope inspection of the high pressure turbine (HPT) stage 1 inner rotating airseal (TOBI ID seal) for oil wetting after an in-flight shutdown (IFSD). It also requires, if necessary, the tear down and inspection of HPT hardware. This amendment is prompted by reports of overheat damage to the HPT hardware caused by ignition of oil that leaked into the HPT from the No. 4 bearing compartment during an IFSD. The actions specified in this AD are intended to prevent failure of the HPT hardware due to ignition of oil trapped by the HPT TOBI ID seal, which could result in an uncontained engine failure and damage to the airplane.
AD 99-12-06 · published Jun 11, 1999, effective Jul 23, 1999
AlliedSignal Inc. VN 411B Very High Frequency (VHF) Navigation Receivers
This amendment adopts a new airworthiness directive (AD) that requires replacing certain AlliedSignal Inc. VN 411B VHF navigation receivers installed on aircraft if the receivers do not have Modification 21 incorporated. This AD is the result of a report of navigation receiver interference during landing operations. The actions specified by this AD are intended to prevent VHF navigation receiver interference from frequency modulation (FM) radio station broadcasts, which could cause distortion of the navigation audio and deflection of the desired flight path of the airplane during landing operations with possible loss of control of the airplane.
AD 99-14-02 · published Jun 28, 1999, effective Aug 17, 1999
BLANIK LIMITED Gliders
This amendment adopts a new airworthiness directive (AD) that applies to certain LET Aeronautical Works (LET) Model L33 SOLO sailplanes. This AD requires replacing the main wing attachment and wing spar root pins and modifying the corresponding area. 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 structural failure of the wing attachments caused by the current design configuration, which could result in the wing separating from the sailplane with consequent loss of control.
