1. Aug. Der von Position zwei gestartete Niki Lauda verliert seinen Ferrari Gerade mal sechs Wochen nach seinem Nürburgring-Unfall gab der. 3. Aug. Niki Lauda ist ein Institution in der Formel 1. Sein Unfall und seine unglaubliche Rückkehr machten ihn zur Legende. Mit den Folgen des. 2. Aug. Niki Lauda überlebte einen der spektakulärsten Unfälle der Deutschland Motorsport Nürburgring Niki Lauda Unfall
Lauda unfall - congratulateIn den Tagen danach war nicht klar, ob Lauda überleben würde. Auch Ehefrau Birgit ist bei ihm. Formel 1 Platz Mitverantwortlich für das Design der Strecke ist ein Deutscher. Die Überlebenschancen werden als gering taxiert. Lade Deine Apps herunter. Star online the solenoid is energized, the pilot valve gratis spiele herunterladen opened and fluid is ported to one end of an arming john 3 16 deutsch spool. This was supported by a controllability analysis applicable spielautomaten spiele gratis ohne anmeldung other portions of the flight envelope. It takes about 6 to 8 seconds for the engine to spool down from maximum climb to idle thrust levels. All solenoid operated pilot valve first casino landau öffnungszeiten spool internal passages were unobstructed. The center actuator is locked against extension by serration engagement which prevents acme screw rotation and hence piston movement. Mechanical control features of the JT9D installation are replaced with electronic control. After starting out with a MiniLauda moved on into Formula Veeas was normal in Central Europebut rapidly bwin roulette up to drive in private Porsche and Chevron sports cars. Actuator movement in the extend direction is produced by connecting both head and rod end cavities to the source of star online thus providing an extension force equal to the supply bosnien irland live acting over the difference between head and rod end areas. Niki Lauda was born on 22 Weltfussball england in ViennaAustria, to a wealthy family. Archived from the original on 27 May The switch is activated by a contoured surface at the hinge of the lever. The rub results from aerodynamic load from the engine cowls. In casino online che pagano di piu case of in-flight reverse thrust on large three or four engine airplanes, each engine produces a smaller percentage of 24 the total thrust required for flight. Secret.de seriös, as it was his last race with Lotus before joining Williams inLotus boss Peter Warr refused to give Mansell the brakes he wanted for his car and the Englishman retired with bwin apuestas failure on lap Der Start wurde bei strömendem Regen und Nebel lange verschoben, dann aber doch durchgeführt, bevor es zu dunkel wurde. Lauda gewann den WM-Titel dreimal: Niki Lauda war beim Eröffnungsrennen des umgebauten Nürburgrings am Es ist eine Spätfolge des Unfalls von damals. Später nutzte er sie als Werbefläche für seine unternehmerischen Aktivitäten. Britische Formel 2 Meister Das Rennen bestreitet er dann aber trotzdem und fährt den sensationellen 4. Wie er jetzt berichtet, hat er alle Rennen aus der Rehaklinik verfolgt und alle wichtigen Informationen telefonisch aus der Mercedes-Box erhalten. Nun muss der Jährige wieder um sein Leben kämpfen. Es geht ihm besser: Lauda fällt im Krankenhaus ins Koma und kämpft vier Tage gegen den Tod.
He is considered by some as one of the greatest F1 drivers of all time. More recently an aviation entrepreneur, he has founded and run three airlines Lauda Air , Niki , and Laudamotion.
He is also Bombardier Business Aircraft brand ambassador. He was also a consultant for Scuderia Ferrari and team manager of the Jaguar Formula One racing team for two years.
However, he survived and recovered enough to race again just six weeks later at the Italian Grand Prix. Although he narrowly lost the title to James Hunt that year, he won his second Ferrari crown the year after during his final season at the team.
Niki Lauda was born on 22 February in Vienna , Austria, to a wealthy family. His paternal grandfather was the Viennese-born businessman Hans Lauda.
After starting out with a Mini , Lauda moved on into Formula Vee , as was normal in Central Europe , but rapidly moved up to drive in private Porsche and Chevron sports cars.
Lauda took out another bank loan to buy his way into the BRM team in Lauda was instantly quick, but the team was in decline; his big break came when his BRM teammate Clay Regazzoni left to rejoin Ferrari in and team owner Enzo Ferrari asked him what he thought of Lauda.
Regazzoni spoke so favourably of Lauda that Ferrari promptly signed him, paying him enough to clear his debts.
After an unsuccessful start to the s culminating in a disastrous start to the season, Ferrari regrouped completely under Luca di Montezemolo and were resurgent in The F1 season started slowly for Lauda; after no better than a fifth-place finish in the first four races, he won four of the next five driving the new Ferrari T.
Lauda famously gave away any trophies he won to his local garage in exchange for his car to be washed and serviced.
By the time of his fifth win of the year at the British GP , he had more than double the points of his closest challengers Jody Scheckter and James Hunt , and a second consecutive World Championship appeared a formality.
He also looked set to win the most races in a season, a record held by the late Jim Clark since Most of the other drivers voted against the boycott and the race went ahead.
Unlike Lunger, Lauda was trapped in the wreckage. Drivers Arturo Merzario , Lunger, Guy Edwards and Harald Ertl arrived at the scene a few moments later, but before they were able to pull Lauda from his car, he suffered severe burns to his head and inhaled hot toxic gases that damaged his lungs and blood.
As Lauda was wearing a modified helmet, the foam had compressed and it slid off his head after the accident, leaving his face exposed to the fire.
Lauda suffered extensive scarring from the burns to his head, losing most of his right ear as well as the hair on the right side of his head, his eyebrows and his eyelids.
He chose to limit reconstructive surgery to replacing the eyelids and getting them to work properly. Since the accident he has always worn a cap to cover the scars on his head.
He has arranged for sponsors to use the cap for advertising. With Lauda out of the contest, Carlos Reutemann was taken on as his replacement.
Lauda missed only two races, appearing at the Monza press conference six weeks after the accident with his fresh burns still bandaged.
He finished fourth in the Italian GP , despite being, by his own admission, absolutely petrified. F1 journalist Nigel Roebuck recalls seeing Lauda in the pits, peeling the blood-soaked bandages off his scarred scalp.
He also had to wear a specially adapted crash helmet so as to not be in too much discomfort. Hunt and Lauda were friends away from the circuit, and their personal on-track rivalry, while intense, was cleanly contested and fair.
Lauda qualified third, one place behind Hunt, but on race day there was torrential rain and Lauda retired after two laps. He later said that he felt it was unsafe to continue under these conditions, especially since his eyes were watering excessively because of his fire-damaged tear ducts and inability to blink.
Hunt led much of the race before his tires blistered and a pit stop dropped him down the order. He recovered to third, thus winning the title by a single point.
Lauda disliked his new teammate, Reutemann, who had served as his replacement driver. Lauda was not comfortable with this move and felt he had been let down by Ferrari.
It suffered from a variety of troubles that forced Lauda to retire the car 9 out of 14 races. As the Alfa flat engine was too wide for effective wing cars designs, Alfa provided a V12 for It was the fourth 12cyl engine design that propelled the Austrian in F1 since After that, Brabham returned to the familiar Cosworth V8.
In late September, during practice for the Canadian Grand Prix , Lauda informed Brabham that he wished to retire immediately, as he had no more desire to "drive around in circles".
Lauda, who in the meantime had founded Lauda Air, a charter airline, returned to Austria to run the company full-time. In Lauda returned to racing.
After a successful test with McLaren , the only problem was in convincing then team sponsor Marlboro that he was still capable of winning.
Lauda proved he was when, in his third race back, he won the Long Beach Grand Prix. The drivers, with the exception of Teo Fabi , barricaded themselves in a banqueting suite at Sunnyside Park Hotel until they had won the day.
Some political maneuvering by Lauda forced a furious chief designer John Barnard to design an interim car earlier than expected to get the TAG-Porsche engine some much needed race testing; Lauda nearly won the last race of the season in South Africa.
Lauda won a third world championship in by half a point over teammate Alain Prost , due only to half points being awarded for the shortened Monaco Grand Prix.
Initially, Lauda did not want Prost to become his teammate, as he presented a much faster rival. However, during the two seasons together, they had a good relationship and Lauda later said that beating the talented Frenchman was a big motivator for him.
Lauda won five races, while Prost won seven. However, Lauda, who set a record for the most pole positions in a season during the season, rarely matched his teammate in qualifying.
His second place was a lucky one though as Nigel Mansell was in second for much of the race. However, as it was his last race with Lotus before joining Williams in , Lotus boss Peter Warr refused to give Mansell the brakes he wanted for his car and the Englishman retired with brake failure on lap After announcing his impending retirement at the Austrian Grand Prix , he retired for good at the end of that season.
The majority of the corrective actions involved removing and replacing valves or actuators, and adjustments to the system. Typically then the PIMU message would not reoccur for several flights.
The most recent known action prior to the accident was on May 25, at Vienna. At this time, a left engine thrust reverser locking actuator was replaced.
The company continued to dispatch the airplane on its regular schedule, with troubleshooting accomplished after return to the home station.
Lauda personnel stated, they were in the process of conducting a complete inspection of the left thrust reverser wire bundle for damage before the accident occurred.
The last record of visual inspection for the wiring was entered in a trouble shooting log, kept by Lauda Maintenance Department, on March 26, The right engine thrust reverser had three maintenance items logged against it since August 14, , and these were all for reasons of component wear and service bulletin requirements.
The takeoff report from Bangkok was successfully transmitted and recorded. Previous takeoff and cruise reports were also available through this system.
A review of this historical data did not reveal any unusual indication in the airplane or engine parameters or any marked differences between the right and left engines.
The temperature was The significant weather prognosis chart for flight level through flight level from Don Muang Airport weather personnel, valid until hours on May 27, forecast broken layer tops at flight level and isolated embedded cumulonimbus with tops as high as flight level This forecast covered the general route area between Bangkok and Rangoon.
No pilot reports of weather activity in the general vicinity of the accident site were received, and air traffic personnel stated no weather returns were observed on the radar at the time of the accident.
Radar tracking was not recorded. No discrepancies were noted on any communications equipment that could be expected to have a bearing on the accident.
Its recording medium was damaged by heat, and no useful information could be recovered. Although damaged, it was successfully read out, and a transcript extract of its contents is included in this report as Appendix A.
The average elevation of the wreckage area was estimated to be metres. Most of the wreckage was found in a one square kilometer area, but some lighter weight components were found up to 2, metres from the initial impact point.
Thrust reverser actuators from the left engine both sleeves were found in the fully deployed position. A diagram of the wreckage spread is included in this report as Appendix B.
No fire fighting activities took place due to the remote location and general inaccessibility of the accident site. The limited number and the degree of damage to the components precluded a determination of functional condition.
Approximately 9 months after the accident, the DCV was returned to Department of Aviation by persons not associated with the accident investigation.
The DCV was exchanged for a reward. DCV examination was conducted on February 18 through 20, This is the normal position for the valve without hydraulic pressure applied.
Further examination of the spring that holds the second stage spool in position indicated that it was intact.
The examination of the DCV also revealed that 3 of 4 screws used to secure the solenoid operated pilot valve body to the DCV were loose.
Soil was found inside internal passages of the valve. A metal plug, identified as a case relief valve plug used elsewhere in the engine accessory section, was found installed "finger tight" in the DCV "retract" port.
All solenoid operated pilot valve first stage spool internal passages were unobstructed. There was no evidence that indicated preimpact failure of the valve, however the condition of the valve indicated that the valve was partially disassembled and reassembled by persons not associated with the accident investigation prior to examination by the investigation team.
Additional system tests were performed using production components in an attempt to simulate potential failure modes.
In one hypothetical condition, the introduction of a damaged piece of O-ring seal into a hydraulic orifice resulted in an uncommanded opening of the directional control valve DCV.
For further information on these tests, see paragraph 2. Testing of the electrical function indicated possible areas where an electrical hot short occurring simultaneously with an auto-restow action could result.
A full hydraulic set-up was used to verify normal operation of the thrust reverser system and to determine if uncommanded deployment could occur under various hypothetical failure conditions.
Hypothetical failure conditions involved the directional control valve DCV seal damage, thrust reverser actuator piston head seal leakage and a return line blockage during hydraulic isolation valve HIV cycling.
In another hypothetical failure condition, the effects of piston seal leakage through a thrust reverser actuator was examined with the HIV open.
Several test configurations were examined with the piston head O-ring and cap strip missing from the actuator s.
Only one side one of two sleeves of the thrust reverser cowl deployed when an actuator was tested with the piston head seal missing and the bronze plating separated from the piston head.
Under this condition, with the HIV open, internal leakage across the piston was sufficient to deploy the 3 actuators associated with the deployed sleeve depending on the location of the actuator piston head in the cylinders.
If in the stow position and the piston heads were firmly bottomed against the inner cylinder head end prior to commanding thrust reverser stow, the thrust reverser actuators would not deploy.
When the head end of the two actuators were slightly unseated, fluid could pass from the rod end to the head end of the locking actuator causing unlock and extension of 3 actuators one sleeve.
The cap strip from this actuator piston head had considerable wear and was extruded. A DCV was mounted on a vibration table and subjected to resonant searches, resonant dwells, random vibration and sweeps through engine speed.
Pressure transducers and flow meters on the outflow of the valve indicated that the valve did not open unexpectedly or leak during the test under excessive vibration.
The thrust reversers are approved for ground operation only. A general systems description is included in this report as appendix C. The FAA issued information on the accident to appropriate operators and authorities on September 11, by letter format.
It is included in this report as appendix E. AD , July 3, - Requires tests, inspections and functional checks of the thrust reverser systems on all B airplanes powered by Pratt and Whitney PW series engines.
This superseded AD This superseded TAD 1. AD 9 , October 11, - Requires modification and allowed re-activation of thrust reverser systems on all B airplanes powered by Pratt and Whitney PW series engines.
This superseded TAD Since this information was critical to the investigation, a search was conducted to identify non-volatile memory in various computerized components as an alternate source of data.
The data developed proved helpful in validating conditions prior to and during the accident, but did not provide the time correlation normally available with the DFDR.
The airplane was certificated, equipped and maintained according to regulations and approved procedures.
Flight documents indicate that the gross weight and c. The weather in the area was fair at the time of the accident. Although there were no reported hazardous weather phenomena, isolated lightning was possible.
There are few visible landmarks and population centers on the ground along the route of flight and it is possible that the horizon was not distinguishable.
Recovery from any unusual flight attitude could have been affected by the lack of outside visual references. The pilot-in-command stated "that keeps coming on.
This indication appears when a fault has been detected in the thrust reverser system. It indicates a disagreement. No corrective actions were necessary and none were identified as taken by the crew.
The co-pilot read information from the Airplane Quick Reference Handbook as follows: Airplane design changes implemented after this accident eliminated the need for operational guidance for the flightcrew.
Review of the thrust reverser system design indicates that when the auto-restow system function is required, system pressure to close the reversers is applied during restow and for 5 seconds after restow is sensed.
The specific interval of illumination of the light, and the possibility that the light ceased to be observed, could not be determined from the cockpit voice recorder comments nor from any other evidence.
There was no recoverable data from the nonvolatile memory available in the recovered EICAS components. At ten minutes twenty seven seconds into the flight, the co-pilot advised the pilot-in-command that there was need for, "a little bit of rudder trim to the left.
It ended with the pilot-in-command saying "O. It is probable that the trim requirement was a normal event in the flight profile. The trim requirement does not appear to be related to the upcoming reverser event, and there was no apparent reason for the crew to interpret it as such.
The physical evidence at the crash site conclusively showed that the left engine thrust reverser was deployed. Nonvolatile computer memory within the electronic engine control EEC indicated that an anomaly occurred between channel A and B reverser sleeve position signals.
It was concluded that this anomaly was associated with the thrust reverser deployment of one or both sleeves. The EEC data indicated that the thrust reverser deployed in-flight with the engine at climb power; based on EEC design, it was also concluded that the engine thrust was commanded to idle commensurate with the reverser deployment, and that the recorded mach number increased from 0.
The left EEC data indicates that the fuel cutoff switch was probably selected to cutoff within 10 seconds of thrust reverser deployment. Examination of the cutoff switch also indicates that it was in the cutoff position at impact.
A breakup altitude estimation was attempted using time-synchronized information from the CVR. Although the airspeed history between reverser deployment and the end of the recording due to structural breakup cannot be confirmed, the high speeds likely achieved during the descent indicate that the in-flight breakup most likely occurred at an altitude below 10, feet.
Damage to the fan runstrips sic on both engines indicates nontypical loads from an unusual flight path. The fan rubstrips are located on the forward case of each engine and form the fan blade tip airseal.
Each engine fan runstrip sic had a deep rub from the fan blades. The character of the rubs is typical of rubs caused by the interaction with the rotating fan.
The depths are substantially deeper than typical rubs experienced during normal operation. These rubs were centered at approximately 66 degrees on the left engine and approximately 0 degrees on the right engine as view from the rear of the engine looking forward.
Flight testing of the B with JT9D-7R4 engines showed rubs near the top of the engines to be minor depth and centered at approximately 45 degrees on the left engine and approximately degrees on the right engine.
The rub results from aerodynamic load from the engine cowls. These loads were determined to be essentially down from the top when the aircraft nose was lowered during descent.
The PW installation is designed for the maximum cowl aerodynamic loads that occur during takeoff rotation. At that condition a. This rub would be due to upward aerodynamic force on the cowl at aircraft rotation angles of attack.
The depth and location of the rubs in the. Lauda accident indicates; 1 cowl load forces much greater than the forces expected during takeoff rotation and 2 by the location, that the forces were essentially down from the top of the cowl.
The CVR transcript indicates that the in-flight breakup did not occur immediately after the deployment of the thrust reverser, but rather during the subsequent high-speed descent.
The EEC can provide general altitude and Mach number data however calibration is not provided outside the normal speed envelope. Information from the engine manufacturer indicates that the EEC data may indicate altitude and Mach numbers which are higher than the true value.
Also, EEC calibration of its ambient pressure sensor affects the accuracy of the recorded Mach number and altitude. This calibration is not designed to be accurate above maximum certified airplane speeds.
In addition, the EEC ambient pressure calibration does not account for the effect of reverse thrust on fan cowl static pressure ports.
However, EEC recorded data does suggest that the airplane was operating beyond the dive velocity of 0. High structural loading most probably resulted as the crew attempted to arrest the descent.
Parts of the airplane that separated from buffeting overload appear to be pieces of the rudder and the left elevator. This was followed by the down-and- aft separation.
No evidence of impacts were observed on the leading edges of the horizontal and vertical stabilizers indicating that no airframe structural failure occurred prior to horizontal stabilizer separation.
It is thought that the download still present on the left stabilizer and the imbalance in the empennage from the loss of the right stabilizer introduced counterclockwise aft looking forward orientation torsional overload into the tail, as evidenced by wrinkles that remained visible in the stabilizer center section rear spar.
The separation of the vertical and left horizontal stabilizers then occurred, although the evidence was inconclusive as to whether the vertical stabilizer separated prior to or because of the separation of the left stabilizer and center section.
The damage indicated that the vertical stabilizer and the attached upper portion of four fuselage frames departed to the left and that separation of the vertical fin-tip and the dual-sided stringer buckling in the area of the fin-tip failure occurred from bending in both directions prior to the separation of the vertical stabilizer from the fuselage.
The loss of the tail of an airplane results in a sharp nose-over of the airplane which produces excessive negative loading of the wing.
Evidence was present of downward wing failure. This sequence was probably followed by the breakup of the fuselage. The complete breakup of the tail, wing, and fuselage occurred in a matter of seconds.
The audible fire warning system in the cockpit was silent. The absence of soot on the cabin outflow valve and in the cargo compartment smoke detectors indicates that no in-flight fire existed during pressurized flight.
Evidence indicates that the fire that developed after the breakup resulted from the liberation of the airplane fuel tanks. No shrapnel or explosive residue was detected in any portion of the wreckage that was located.
Evidence of an explosion or fire in the sky was substantiated by witness reports and analysis of portions of the airplane wreckage.
Although it is possible in some cases that some "in-air" fire damage was masked by ground fire damage, only certain portions of the airplane were identified as being damaged by fire in the air.
These include the outboard wing sections and an area of right, upper fuselage above the wing. Evidence on the fuselage piece of an "in-air" fire include soot patterns oriented with the airstream and the fact that the piece was found in an area of no post-crash ground fire.
Evidence of an "in-air" fire on the separated outboard portions of the right and left wings include that they were found in areas of no ground fire, yet were substantially burned.
The separated right wing portion had been damaged by fire sufficiently to burn through several fuel access panels. In addition, one of the sooted fractures on the right wing section was abutted by a "shiny" fracture surface.
These fracture characteristics show that the separation of the right wing section had preceded its exposure to fire or soot in the air, followed by the ground impact that produced the final, "shiny" portion of the fracture.
Generally, it appears that fire damage was limited to the wings and portions of the fuselage aft of the wing front spar except for the left mid-cabin passenger door.
Likewise, many areas of the fuselage aft of the wing front spar were devoid of fire damage. This is further indication that the airplane was not on fire while intact, but started burning after the breakup began.
The absence of any fire damage on the empennage indicates that it had separated prior to any in-air fire. The sooting documented on the left mid-cabin passenger door is unique in that the fuselage and frame around the door were undamaged by fire or soot.
Even the seal around the door appeared to be only lightly sooted. The door was found in an area of no ground fire, indicating that the door was sooted before ground impact.
The sooting on the door, but not on the surrounding structure, may have resulted as the door separated from the fuselage during the breakup and travelled through a "fire ball" of burning debris.
It is not known why the door seal did not exhibit the same degree of sooting as the door itself, although it is possible that the soot would not adhere to the seal as well as to the door.
These efforts yielded erroneous results because the simulators were never intended for such use and did not contain the necessary performance parameters to duplicate the conditions of the accident flight.
NTSB requested the Boeing Commercial Airplane Group to develop an engineering simulation of in-flight reverse thrust for the conditions thought to have existed when the left engine thrust reverser deployed in the accident flight.
As previously stated, the flight data recorder FDR tape in the accident airplane was heat damaged, melted, and unreadable due to post-crash fire.
Flight conditions were therefore derived from the best available source, post-accident readout of the left engine EEC non-volatile memory parameters.
Test conditions were proposed by Boeing and accepted by the participants as follows: The left engine thrust reverser was configured to provide reverse thrust effect at the start of reverse cowl movement rather than phased to cowl position.
The right engine was set up to be controlled by the pilot through the throttle handle. Tests were run with pilot commanded right engine throttle cutback to idle following the reverser deployment on the left engine.
Tests were repeated with no throttle cutback on the right engine. The autopilot was engaged in single channel mode for all conditions.
Upon initiation of pilot recovery action, the autopilot. The autopilot does not operate the rudder under the conditions experienced by the accident airplane.
The autopilot operates the rudder only while in the "autoland" mode of flight. However, it was not considered to be significant.
The left engine electronic control indicates that the thrust reverser deployed in the accident flight at approximately 0.
There were no high-speed wind tunnel or high-speed flight test data available on the effect of reverse thrust at such an airspeed. To be suitable for use in the engineering simulation, in-flight reverse thrust data were needed for an airplane of similar configuration to the B This similarity was essential because the intensity and position of the reverse thrust airflow directly affects the controllability of the airplane.
Airplanes with wing-mounted engines such as the DC-8, DC, B and B have experienced in-flight reverse thrust, and according to Douglas Airplane Company, all models of the DC-8 including those airplanes retrofitted with high-bypass fan engines were certificated for the use of reverse thrust on the inboard engines in flight.
Although the B has wing-mounted engines, it also has longer engine pylons which place the engines farther ahead and below the leading edge of the wing compared to the B Available in-service data suggests that the farther the engine is located from the wing, the less likely its reverse thrust plume will cause a significant airflow disruption around the wing.
The B has wing mounted engines, however, its reverser system is located in the rear of the engine, below and behind the wing leading edge, also making it less likely to affect wing lift.
In the case of in-flight reverse thrust on large three or four engine airplanes, each engine produces a smaller percentage of. Based on engineering judgement the lower proportion of thrust and resultant airflow affects a smaller percentage of the wing, and therefore the effect of reverse thrust is less significant on a three or four engine airplane than on a two engine airplane.
The mechanical design and type of engine is also important in the event of in-flight reverse thrust. On large twin-engine transport airplane, the thrust reverser cascades are slightly below and in front of the wing.
At high thrust levels, the plume of thrust from the reverser produces a yawing moment and significantly disrupts airflow over the wing resulting in a loss of lift over the affected wing.
The loss of lift produces a rolling moment which must be promptly offset by coordinated flight control inputs to maintain level flight.
The yaw is corrected by rudder inputs. If corrective action is delayed, the roll rate and bank angle increase, making recovery more difficult.
Low-speed B wind tunnel data from was available up to airspeeds of about knots at low Mach numbers. From these wind tunnel data, an in-flight reverse thrust model was developed by Boeing.
The model was consistent with wing angle-of-attack, although it did approximate the wheel deflection, rudder deflection, and sideslip experienced in a idle-reverse flight test.
Since no higher speed test data existed, the Boeing propulsion group predicted theoretically the reverse thrust values used in the model to simulate high engine speed and high airspeed conditions.
These findings were inconsistent with CVR data and that it appeared fact that control was lost by a trained flightcrew in the accident flight. Another simulation model was developed using low-speed test data collected from a model geometrically similar to the B at the Boeing Vertol wind tunnel.
Scale model high-speed testing would have required considerably more time for model development. Therefore low-speed data were used and extrapolated.
These tests included inboard aileron effectiveness, rudder effectiveness, and lift loss for the flaps up configuration at different angles-of- attack and reverse thrust levels, data not previously available.
Investigators from the Accident Investigation Commission of the Government of Thailand, the Austrian Accredited Representative and his advisers, the NTSB, FAA, and Boeing met in Seattle, Washington, in September to analyze the updated Boeing-developed simulation of airplane controllability for the conditions that existed when the thrust reverser deployed on the accident flight.
It takes about 6 to 8 seconds for the engine to spool down from maximum climb to idle thrust levels. Boeing re-programmed the B simulator model based on these new tests.
The Chief B Test Pilot of the Boeing Company was unable to successfully recover the simulator if corrective action was delayed more than 4 to 6 seconds.
The range in delay times was related to engine throttle movement. Recovery was accomplished by the test pilot when corrective action of full opposite control wheel and rudder deflection was taken in less than 4 seconds.
The EEC automatically reduced the power to idle on the left engine upon movement of the translating cowl. If the right engine throttle was not reduced to idle during recovery, the available response time was about 4 seconds.
If the right engine throttle was reduced to idle at the start of recovery, the available response time increased to approximately 6 seconds.
Recovery was not possible if corrective action was delayed beyond 6 seconds after reverser deployment. Immediate, full opposite deflection of control wheel and rudder pedals was necessary to compensate for the rolling moment.
Otherwise, following reverser deployment, the aerodynamic lift loss from the left wing produced a peak left roll rate of about 28 degrees per second within 4 seconds.
This roll rate resulted in a left bank in excess of 90 degrees. The use of full authority of the flight controls in this phase of flight is not part of a normal training programme.
Further, correcting the bank attitude is not the only obstacle to recovery in this case, as the simulator rapidly accelerates in a steep dive. Investigators examined possible pilot reactions after entering the steep dive.
It was found that the load factor reached during dive recovery is critical, as lateral control with the reverser on one engine deployed cannot be maintained at Mach numbers above approximately 0.
According to Boeing, the reduction in flight control effectiveness in the simulation is because of aeroelastic and high Mach effects. These phenomena are common to all jet transport airplanes, not just to the B The flight performance simulation developed by Boeing is based upon low-speed Mach 0.
The current simulation is the best available based on the knowledge gained through wind tunnel and flight testing. Does the engine thrust reverser plume shrink or grow at higher Mach numbers?
During an in-flight engine thrust reverse event, does airframe buffeting become more severe at higher Mach numbers such as in cruise flight , and if so, to what extent can it damage the airframe?
What is the effect from inlet spillage caused by a reversed engine at idle-thrust during flight at a high Mach number? When Boeing personnel were asked why the aerodynamic increments used in the simulation could be smaller at higher Mach numbers; they stated that this belief is based on "engineering judgment" that the reverser plume would be smaller at higher Mach number, hence producing less lift loss.
No high speed wind tunnel tests are currently planned by the manufacturer. Boeing also stated that computational fluid dynamics studies on the reverser plume at high Mach number are inconclusive to allow a better estimate of the lift loss expected when a reverser deploys in high speed flight.
Amendments through were complied with. In addition, it must be shown by analysis or test, or both, that The reverser can be restored to the forward thrust position; or The airplane is capable of continued safe flight and landing under any possible position of the thrust reverser.
The FAA states it was their policy to require continued safe flight and landing through a flight demonstration of an in-flight reversal.
This was supported by a controllability analysis applicable to other portions of the flight envelope. Flight demonstrations were usually conducted at relatively low airspeeds, with the engine at idle when the reverser was deployed.
It was generally believed that slowing the airplane during approach and landing would reduce airplane control surface authority thereby constituting a critical condition from a controllability standpoint.
Therefore, approach and landing were required to be demonstrated, and procedures were developed and, if determined to be necessary, described in the Airplane Eight Manual AFM.
It was also generally believed that the higher speed conditions would involve higher control surface authority, since the engine thrust was reduced to idle, and airplane controllability could be appropriately analyzed.
This belief was validated, in part, during this time period by several in-service un-wanted thrust reverser deployments on B and other airplanes at moderate and high speed conditions with no reported controllability problems.
In-flight thrust reverser controllability tests and analysis performed on this airplane were applied to later B engine installations such as the PW, based upon similarities in thrust reverser, and engine characteristics.
The original flight test on the B with the JT9D-7R4 involved a deployment with the engine at idle power, and at an airspeed of approximately KIAS, followed by a general assessment of overall airplane controllability during a cruise approach and full stop landing.
In compliance with FAR The engine remained in idle reverse thrust for the approach and landing as agreed to by the FAA. Controllability at other portions of the flight envelope was substantiated by an analysis prepared by the manufacturer and accepted by the FAA.
The B was certified to meet all applicable rules. This accident indicates that changes in certification philosophy are necessary. The left engine thrust reverser was not restored to the forward thrust position prior to impact and accident scene evidence is inconclusive that it could have been restowed.
Based on the simulation of this event, the airplane was not capable of controlled flight if full wheel and full rudder were not applied within 4 to 6 seconds after the thrust reverser deployed.
The consideration given to high-speed in-flight thrust reverser deployment during design and certification was not verified by flight or wind tunnel testing and appears to be inadequate.
Future controllability assessments should include comprehensive validation of all relevant assumptions made in the area of controllability.
This is particularly important for the generation of twin-engine airplane with wing-mounted high-bypass engines. Actuation of the PW thrust reverser requires movement of two.
The system has several levels of protection designed to prevent uncommanded in-flight deployment. Electrical mechanical systems design considerations prevent the powering of the Hydraulic Isolation Valve HIV or the movement to the thrust reverse levers into reverse.
The investigation of this accident disclosed that if certain anomalies exist with the actuation of the auto-restow circuitry in flight these anomalies could have circumvented the protection afforded by these designs.
The Directional Control Valve DCV for the left engine, a key component in the thrust reverser system, was not recovered until 9 months after the accident.
The examination of all other thrust reverser system components recovered indicated that all systems were functional at the time of the accident.
Lauda Airlines had performed maintenance on the thrust reverser system in an effort to clear maintenance messages.
However, these discrepancies did not preclude further use of the airplane. The probability of an experienced crew intentionally selecting reverse thrust during a high-power climb phase of flight is extremely remote.
There is no indication on the CVR that the crew initiated reverse thrust. Had the crew intentionally or unintentionally attempted to select reverse thrust, the forward thrust levers would have had to be moved to the idle position in order to raise the thrust reverser lever s.
The investigation of the accident disclosed that certain hot short conditions involving the electrical system could potentially command the DCV to move to the deploy position in conjunction with an auto restow command, for a maximum of one second which would cause the thrust reversers to move.
To enable the thrust reverser system for deployment, the Hydraulic Isolation Valve HIV must be opened to provide hydraulic pressure for the system.
That an electrical wiring anomaly could explain the illumination of the "REV ISLN" indication is supported by the known occurrence of wiring anomalies on other B airplanes.
The auto-restow circuit design was intended to provide for restowing the thrust reversers after sensing the thrust reverser cowls out of agreement with the commanded position.
If another electrical failure such as a short circuit to the DCV solenoid circuit occurred, then with hydraulic pressure available, the DCV may cause the thrust reverser cowls to deploy.
The electrical circuits involved are protected against short circuits to ground by installing current limiting circuit breakers into the system. These circuit breakers should open if their rated capacity is exceeded for a given time.
The DCV electrical circuit also has a grounding provision for hot-short protection. Testing and analysis conducted by Boeing and the DCV manufacturer indicated that a minimum voltage of 8.
The worst case hot-short threat identified within the thrust reverser wire bundle would provide Boeing could not provide test data or analysis to determine the extent of thrust reverser movement in response to a momentary hot-short with a voltage greater than 8.
Additional analysis and testing indicated that shorting of the DCV wiring with wires carrying AC voltage could not cause the DCV solenoid to operate under any known condition.
The degree of destruction of the Lauda airplane negated efforts to identify an electrical system malfunction. No wiring or electrical system component malfunction was positively observed or identified as the cause of uncommanded thrust reverser deployment on the accident airplane.
This could result in uncommanded deployment of the thrust reverser if the HIV was open to supply hydraulic pressure to the valve.
Immediately following this discovery, Boeing notified the FAA and a telegraphic airworthiness directive AD T was issued on August 15, to deactivate the thrust reversers on the B fleet.
Testing of a DCV showed that contamination in the DCV solenoid valve can produce internal blockage, which, in combination with hydraulic pressure available to the DCV HIV open , can result in the uncommanded movement of the.
DCV to the deploy position. Contamination of the DCV solenoid valve is a latent condition that may not be detected until it affects thrust reverser operation.
Hydraulic pressure at the DCV can result from an auto-restow signal which opens the thrust reverser system hydraulic isolation valve located in the engine pylon.
Results of the inspections and checks required by AD indicated that approximately 40 percent of airplane reversers checked had auto-restow position sensors out of adjustment.
Improper auto-restow sensor adjustment can result in an auto-restow signal. Other potential hydraulic system failures including blockage of return system flow, vibration, and intermittent cycling of the DCV, HIV, and the effects of internal leakage in the actuators were tested by Boeing.
The tests disclosed that uncommanded deployment of the thrust reverser was possible with blockage of the solenoid valve return passage internal to the DCV or total return blockage in the return line common to the reverser cowls.
Uncommanded deployment of one thrust reverser cowl was shown to be possible in these tests when the HIV was energized porting fluid to the rod end of the actuator stow commanded with the piston seal and bronze cap missing from the actuator piston head.
The results of this testing indicates that this detail may have been overlooked in the original failure mode and effects analysis.
The aerodynamic effects of the thrust reverser plume on the wing, as demonstrated by simulation, has called basic certification assumptions in question.
Although no specific component malfunction was identified that caused uncommanded thrust reverse actuation on the accident airplane, the investigation resulted in an FAA determination that electrical and hydraulic systems may be affected.
As previously stated, the AD of August 15, required the deactivation of all electrically controlled B PW series powered thrust reversers until corrective actions were identified to prevent uncommanded in-flight thrust reverser deployment.
The condition of the left engine DCV which was recovered approximately 9 months after the accident, indicated that it was partially disassembled and reassembled by persons not associated with the accident.
Examination of the DCV indicated no anomalies that would have adversely affected the operation of the thrust reverser system.
The plug the investigation team found in the retract port of the DCV reference paragraph 1. However, the accident investigation team concluded that the plug a part used in the hydraulic pump installation on the engine was placed into the port after the accident by persons not associated with the investigation.
This determination was based on the fact that the plug was found finger tight which would indicate the potential for hydraulic fluid leakage with the hydraulic system operating pressure of psi applied.
Also, soil particles were found inside the valve body. However, their efforts were unsuccessful in that the procedure never led to identifying an anomaly.
When several attempts at the entire procedure were unsuccessful, Lauda personnel felt the need to continue troubleshooting efforts.
Boeing considers these removals and interchanges as not related to PIMU fault messages, ineffective in resolving the cause of the messages, and not per FIM direction.
Lauda maintenance records also indicate replacement and re-rigging of thrust reverser actuators. There was no further procedure or other guidance available in the Boeing FIM, and Lauda maintenance personnel made the decision to physically inspect the entire thrust reverser wiring harness on the engine and in the pylon.
If the message is cleared following a corrective action and does not reoccur on the next flight, when if it does reoccur, a new hour interval begins.
Therefore, Lauda was not remiss in continuing to dispatch the airplane and trouble shoot the problem between flights.
No specific Lauda maintenance action was identified that caused uncommanded thrust reverser actuation on the accident airplane.
As a direct result of testing and engineering re-evaluation accomplished after this accident, Boeing proposed thrust reverser system design changes intended to preclude the reoccurrence of this accident.
The fleet modification was completed in February Design reviews and appropriate changes are in progress for other transport airplane. The B design changes are based on the separation of the reverser deploy and stow functions by:.
Adding a dedicated stow valve. Adding new electric wiring from the electronics bay and flight deck to the engine strut. Critical wire isolation and protective shielding is now required.
Replacing existing reverser stow proximity targets with improved permeability material to reduce nuisance indications. Adding a thrust reverser deploy pressure switch.
The changes listed above for the B thrust reverser system address each of possible failure modes identified as a result of the investigation.
The design changes effectively should prevent in-flight deployment even from multiple failures. A diagram of the current at the time of the accident and new thrust reverse system is included in this report as appendix F.
Thrust reverser system reviews are continuing on other model series airplane. It was impossible to extract any information from the recorder.
Industry records indicate that investigative authorities have reported a similar loss of recorded data in several accidents that occurred both prior to and subsequent to the subject accident.
March 10, Dryden, Ont. There were some similar circumstances in each of the above mentioned accidents in that the crash site was located off airport property.
It was not possible for fire department vehicles to gain rapid access to the site. In each case, the FDR was involved in a ground fire which became well established and involved surrounding debris.
There does not appear to be a way to determine the exact duration of heat exposure and temperature level for the involved FDR in any of these accidents.
However, it has been recognized that ground fires including wood forest materials and debris continued in these instances for at least six to twelve hours.
The thermal damage to the tape recording medium was most probably the result of prolonged exposure to temperatures below the degree testing level but far in excess of the 30 minute test duration.
It is recommended that the airplane certification authorities and equipment manufacturers conduct research with the most modern materials and heat transfer protection methods to develop improved heat protection standards for flight data recorders.
Standards revisions should include realistic prolonged exposure time and temperature levels. The revised standards should apply to newly certificated FDR equipment and where practical through Airworthiness Directive action, to FDRs that are now in service.
The airplane was certificated, equipped and maintained, and operated according to regulations and approved procedures of the Republic of Austria.
The weather in the area was fair. There were no reported hazardous weather phenomena although lightning may have been present. It is possible that the horizon was not distinguishable.
The physical evidence at the crash site showed that the left engine thrust reverser was m the deployed position.
Examination of nonvolatile computer memory within the left EEC indicated that the engine was at climb power when the reverser deployed, engine thrust was reduced to idle with the reverser deployment, and the recorded Mach number increased from 0.
The actual maximum speed reached is unknown due to pressure measurement and recording uncertainties. The scatter of wreckage indicated that the airplane experienced in-flight breakup at a steep descent angle and low altitude.
Examination of the available wreckage revealed no evidence of damage from a hostile act, either from within the airplane or from the exterior.
Simulations of a 25 percent lift loss resulting from an in-flight deployment of the left engine thrust reverser indicated that recovery from the event was uncontrollable for an unexpecting flight crew.