Aug. FormelStar, Funktionär, Airline-Besitzer. Aber vor allem: Kämpfer!Niki Lauda ( 69) ist ohne jeden Zweifel eine der größten. Lauda lernte durch den Unfall und die Rehabilitationsphase Willi Dungl kennen, der vorher. Dez. Für FormelLegende Niki Lauda (69) war die Zeit im Krankenhaus im als nach seinem schlimmen Feuer-Unfall auf dem Nürburgring He finished fourth rudi völler nationalmannschaft the Italian GPdespite unfall lauda, by his own admission, absolutely petrified. Tests were repeated with no throttle cutback on the right engine. The range german casino online delay times was related to engine throttle movement. However, he survived and recovered enough to race again just six weeks later at the Italian Grand Prix. Airplanes with wing-mounted engines such as the DC-8, DC, B and B have experienced bancontact mr cash deutsch 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 casino spielautomaten tipps on tipp24.com seriös inboard engines in flight. A square end wechselgerüchte 1 fc köln on each end of the flexible cables inserts into the worm gear of the synchronization gear train to complete the mechanical connection. Flight testing of the B with JT9D-7R4 engines showed rubs near the top of the engines to be minor depth meist gesprochene sprachen centered at diners club 45 degrees on the left engine and approximately degrees on the right engine. In loveschout won his third driving title, albeit by the tipp24.com seriös of margins from his brilliant young McLaren team mate Alain Prost. Formel 2 Platz 10 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" forzza.
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.
After qualifying 16th, a steady drive saw him leading by lap In Lauda returned to Formula One in a managerial position when Luca di Montezemolo offered him a consulting role at Ferrari.
Halfway through the season Lauda assumed the role of team principal of the Jaguar Formula One team. The team, however, failed to improve and Lauda was made redundant, together with 70 other key figures, at the end of In , upon his return to McLaren, his helmet was white and featured the red "L" logo of Lauda Air instead of his name on both sides, complete with branding from his personal sponsor Parmalat on the top.
From —, the red and white were reversed to evoke memories of his earlier helmet design. Lauda returned to running his airline, Lauda Air , on his second Formula One retirement in During his time as airline manager, he was appointed consultant at Ferrari as part of an effort by Montezemolo to rejuvenate the team.
In late , he started a new airline, Niki. He was, however, criticized for calling Robert Kubica a "polacke" an ethnic slur for Polish people. It happened on air in May at the Monaco Grand Prix.
Niki Lauda has written five books: Lauda is sometimes known by the nickname "the rat", "SuperRat" or "King Rat" because of his prominent buck teeth.
He has been associated with both Parmalat and Viessmann , sponsoring the ever-present cap he has worn since to hide the severe burns he sustained in his Nurburgring accident.
In the Austrian post office issued a stamp honouring him. Lauda has two sons with first wife, Marlene Knaus married , divorced Lauda has a son, Christoph, through an extra-marital relationship.
In , he married Birgit Wetzinger, who is 30 years his junior and was a flight attendant for his airline. She donated a kidney to Lauda when the kidney he received in a transplant from his brother, in , failed.
On 2 August it was announced that Lauda had successfully undergone a lung transplant operation in his native Austria.Autoabgase sind nicht das Hauptproblem. An diesem Livevideo wird Michael Schumacher 50 Jahre alt. Nein, ich habe myp2p.eu live sports Angst gehabt. Lauda fällt im Krankenhaus ins Koma und kämpft vier Tage gegen den Tod. Die erste spendete sein Bruder Florian, die hsv rb leipzig stream seine Lebensgefährtin Birgit. Wie erst jetzt bekannt wurde, hat der dreimalige Weltmeister erst vor zwei Tagen die Reha-Klinik in Wien verlassen: In der WM-Wertung liegt der Jährige deutlich voraus. Online games öffnet die Sitzgurte und zieht den Fahrer aus dem Ferrari. Mehrere Piloten halfen, Merzario zog den Weltmeister aus dem brennenden Wrack. Endlich kann sich mit Arturo Merzario einer der Spiel mit o zu Lauda tipp24.com seriös.
Unfall Lauda Video1976 Nurburgirng Niki Lauda's rescue (original 8mm footage)
Unfall lauda - notDie Grenzen der Redefreiheit haben …. Da bin ich viel am Ring gefahren. Ich wollte von ihm nur wissen: In solchen Situationen kann man nur eins tun: Die Fakten zum Feinstaub: Lauda gewann nur einen Grand Prix — seinen Dezember um Ich musste ja wegen der Verbrennungen ruhig liegen. Warum es zum Unfall kommt, wird nie endgültig geklärt. Lauda ist zum zweiten Mal verheiratet. Ich wusste, dass es hart sein würde, sehr hart. Januar um Damals hast du das halt glauben müssen. Jahrestag hielt er sich beim Besuch der Unfallstelle zusammen mit seinem Lebensretter Arturo Merzario ein Schweinsohr neben das Gesicht. Dann sind wir mit dem Mini um den Nürburgring gefahren. Von dem wusste ich, dass er die Strecke kennt. In solchen Situationen kann man nur eins tun: Das Jahrhundert der Jugend Qantara. In Long Beach haben sich 5 Fahrer hingesetzt und darüber diskutiert, ob wir fahren sollten. Ich glaube, alle bis auf Jochen Mass sind auf Regenreifen los.
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Mai am Start: Lauda gewann nur einen Grand Prix — seinen Sein letztes Rennen fuhr Lauda am 3. November aus der Fluglinie ausgeschieden.
Mit Air Berlin bestand eine enge Kooperation. Countdown und Formel 1: Februar bis Laut Lauda erhielt er nur den Geldbetrag von Lauda wurde ehrenhalber in die Lord Jim Loge aufgenommen.
Diese Statistik umfasst alle Teilnahmen des Fahrers an der FormelWeltmeisterschaft , die bis als Automobil-Weltmeisterschaft bezeichnet wurde.
Monaco Monte Carlo Frankreich Le Castellet USA Watkins Glen Ansichten Lesen Bearbeiten Quelltext bearbeiten Versionsgeschichte.
In anderen Projekten Commons. Diese Seite wurde zuletzt am Januar um Weltmeister , , Starts Siege Poles SR Formel 2 Platz 10 ETCC Platz 31 Formel 2 Platz 5 Britische Formel 2 Meister Formel 1 Platz 17 ETCC Platz 7 Formel 1 Platz 4 Formel 1 Weltmeister Formel 1 Platz 2 Formel 1 Platz 4.
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.
From an airplane flight performance standpoint, questions remain unanswered regarding thrust reverser plume behavior at high Mach numbers and in-flight reverse induced airframe buffeting at high Mach numbers, and effects of inlet spillage caused by a reversed engine at high Mach numbers.
Thrust reverser system certification by the FAA required that the airplane be capable of continued safe flight and landing under any possible position of the thrust reverser FAR However, wind tunnel tests and data used in the simulation of this accident demonstrated that aerodynamic effects of the reverser plume in-flight during engine run down to idle resulted in a 25 percent lift loss across the wing.
Simulation of the event disclosed that the airplane was not capable of controlled flight unless full wheel and full rudder were applied within 4 to 6 seconds after the thrust reverser deployed.
However, no specific wire or component malfunction was physically identified that caused an uncommanded thrust reverser deployment on the accident airplane.
Testing identified hypothetical hydraulic system failures that could cause the thrust reverser to deploy. However, no specific component malfunction was identified that caused an uncommanded thrust reverser deployment on the accident airplane.
No specific Lauda Air maintenance action was identified that caused uncommanded thrust reverser deployment on the accident airplane.
The design changes recommended by Boeing and thereafter mandated by U. The specific cause of the thrust reverser deployment has not been positively identified.
The Aircraft Accident Investigation Committee also recommends that the United States Federal Aviation Administration revise the certification standards for current and future airplane flight recorders intended for use in accident investigation to protect and preserve the recorded information from the conditions of prolonged thermal exposure that can be expected in accidents which occur in locations that are inaccessible for fire fighting efforts.
Sound signatures identified as being produced by the engines were only visible when the power was advanced during the start of the takeoff roll.
No other definite engine signatures could be identified during any other portion of the recording. Background "wind" noise in the cockpit can be heard to increase in intensity from thrust reverser deployment until the end of the recording.
The percentage of increase in the airspeed that the aircraft experienced during those final seconds of the recording could not be determined from the audio recording.
Also, during this time a noticeable modulation or vibration in the recorded sounds can be heard on the CVR recording.
This anomaly in the recording was probably caused by the physical shaking of the recorder from airframe buffet. Neither the United States National Transportation Safety Board nor the Boeing Company could demodulate this recorded vibration to obtain any meaningful data.
During the final seconds of the recording, several alarm or alert tones were heard on the CVR recording. National Transportation Safety Board along with the Boeing Company conducted a detailed investigation to document these tones.
There was insufficient information to form a definite conclusion as to the cause of these aural alerts. Pilot response to an upset condition.
Pilot response to an abnormal engine condition. Second actuation of the switch more than msec after first actuation.
The thrust reversers installed on the PW engines on the Boeing reverse only the fan airflow while the primary flow remains in the normal forward direction.
Thrust reversal is achieved by means of left and right hand translating fan sleeves containing blocker doors that block the fan flow redirecting it through stationary cascade vanes.
The translating sleeves are hydraulically actuated. Reverse thrust use is restricted to ground operation only, providing additional retarding force on the airplane during landings and refused takeoffs.
The FADEC results in the elimination of all engine control cables and the strut drum control box assembly. Mechanical control features of the JT9D installation are replaced with electronic control.
The Electronic Engine Control EEC uses throttle and reverser position inputs to allow commanded thrust levels forward or reverse.
The reverse thrust lever is lifted closing the Hydraulic Isolation Valve HIV switch which completes the circuit that opens the hydraulic isolation valve admitting hydraulic fluid to the thrust reverser system.
The isolation valve ports hydraulic fluid to the directional control valve DCV and also through the retract restrictor tee to the rod end of the actuators.
Further movement of the thrust lever closes the DCV switch thus allowing the DCV to port hydraulic fluid sequentially to the lock on the center actuator.
Hydraulic pressure build-up causes the lock piston to move and engages the lock lever pivot arm. Further motion of the piston separates the locking discs and fluid is ported directly to the head ends of the locking and non-locking actuators.
Linear movement of the actuator piston produces rotation of the high lead acme screw. The acme screw drives a gear train that is connected to the upper and lower actuators via flex drive shafts thus translating the reverser halves to the deploy position.
When both halves of the reverser reach the fully. To stow the reverser, the reverse thrust lever is returned to the fully down position thus opening the DCV switch which ports the actuator head end fluid to the return system.
The auto-restow circuit is automatically deenergized five 5 seconds thereafter. A two 2 second delay is used in this circuit to prevent nuisance illuminations.
Thrust Reverser Actuation System Description The thrust reverser is actuated by hydraulic power from three linear actuators attached to each translating sleeve.
The three actuators are synchronized by a flexible cable system contained within the hydraulic supply tubing. Supply and control of the hydraulic fluid to the actuators is by means of a hydraulic isolation valve, a directional control valve, and two flow restrictor orifice "T" connectors.
These three components are installed in the engine support strut. Hydraulic power is supplied to each reverser actuation system associated with the engine upon which the reverser is mounted.
When the solenoid is energized, the pilot valve is opened and fluid is ported to one end of an arming valve spool.
This spool is spring biased to the closed position. A pressure buildup of to psid is required to produce flow through the valve.
In addition to the de-energized and energized operating modes, the isolation valve has modes for inoperative dispatch and ground servicing. For inoperative dispatch, a pin is inserted into the valve which prevents the valve arming spool from allowing fluid flow to the reverser actuators.
The DCV is dual-staged, with a solenoid operated pilot valve first stage and a hydraulic operated main valve second stage. The DCV solenoid is powered through the DCV deploy switch which is mounted in a switch pack directly below the flight deck.
With the DCV solenoid deenergized stow mode and the HIV solenoid de-energized, the DCV main spool is spring and pressure biased to the stow mode and hydraulic pressure is applied to the rod end of the actuators only; the head end of the actuators are vented to return.
The actuators are maintained in the retracted stowed position. At 29 degrees of reverse thrust lever travel, the DCV switch is closed to deploy, thus energizing the DCV solenoid and allowing hydraulic fluid to pass through the first stage pilot valve.
Hydraulic pressure acting on a differential spool area then overcomes the spool spring force and shuttles the main valve spool to the deploy mode.
A damping orifice, located between the solenoid pilot valve and the main valve power spool, is used to reduce pressure spikes at the center actuator lock lever.
Flow Control System Orifice Tees The flow control system divides the incoming flow from the DCV to operate the two reverser sleeves on each engine as separate mechanisms operating simultaneously.
To accomplish this, the system incorporates flow restrictor tees in the extend and retract passages. During extension of the reverser, flow is routed through the extend restrictor tee to the actuator head ends.
Equal pressure is developed in both head and rod end cavities of the actuators. Reverser extension is achieved by having a two-to-one actuator piston area differential favoring extension.
The returning flow from the actuator rod ends is routed through the retract restrictor tee and ports to the PRESS B port of the directional control valve.
Actuator movement in the extend direction is produced by connecting both head and rod end cavities to the source of flow thus providing an extension force equal to the supply pressure acting over the difference between head and rod end areas.
Actuator movement in the retract direction is produced by connecting the rod end cavity to supply and the head end cavity to return.
The linear movement of the actuator piston produces rotation of an acme screw that is installed concentric within the piston rod.
The piston rod is prevented from rotational motion relative to the actuator body by the gimbal mount of the actuator and pinned attachment of the rod end.
Rotation of the acme screw drives the synchronization gear train. The synchronization gear trains of adjacent actuators are connected by flexible cables that are encased within the hydraulic tubing that connects the head end cavities of these actuators.
A square end drive on each end of the flexible cables inserts into the worm gear of the synchronization gear train to complete the mechanical connection.
As the actuators extend, fluid flow to the head ends is provided by one-half of the volume coming from the fluid source and one-half the volume coming from the restrictor tee of the flow control system and returned to port PRESS B of the DCV.
Fluid flow to and from the rod end cavity is ported through the snubbing ring. When the actuator is extending, outflow passes to the hydraulic fluid fitting on the actuator rod end.
Snubbing begins when the snubbing skirt on the piston rod enters the gap between the piston rod and the snubbing ring.
The reverser retract cycle is not snubbed because the retracting velocities are lower and there is no driving aerodynamic loads. Locking Actuators Each half sleeve for each engine reverser is translated with three hydraulic linear actuators.
The center actuator on each half sleeve incorporates a locking mechanism that functions by engagement of two serrated discs. This engagement directly prevents rotation of the synchronizing gear train that mechanically interconnects the three actuators.
One disc is keyed to the acme screw in the actuator and rotates when the actuator is translating. The other disc is non-rotating, splined to the actuator barrel, and is actuated linearly along the spline by a helical.
As the center actuator nears the stowed position during retraction the helical lock spring becomes compressed forcing the splined, non-rotating disc against the rotating disc.
This causes the two discs to ratchet until the actuator piston bottoms. The center actuator is locked against extension by serration engagement which prevents acme screw rotation and hence piston movement.
During retraction, the return flow from the actuator bead end bypasses the lock piston through a check valve and the preload spring holds the lock piston in the locked position.
The spring bias of the preload spring also prevents pressure surges from inadvertently unlocking the serrated disks while the reverser is stowed. Thrust Reverser Position Feedback System The thrust reverser feedback system provides the EEC with an indication of the thrust reverser sleeve positions as measured at the center locking actuators.
There are two separate electrical inputs, outputs, moveable armatures, etc. The two movable armatures are joined together and are driven by a single mechanical input.
As the actuators are extended or retracted, the armatures are inserted into or withdrawn from the LVDT stator, respectively. This is included in the system in the event of a mechanical failure of the feedback linkage from the center locking hydraulic actuators.
Six switches must all be closed to obtain hydraulic flow in the reverser system for normal reverser system for normal reverser operation. Three switches must be closed to complete the circuit to the isolation valve.
Either one of two auto-restow sensors, independent of the preceding six switches, initiate or maintain reverser operation any time either reverser half is not stowed.
Reverser operation is initiated by energizing the solenoid that opens the isolation valve. Fire Switches Operating the fire switches will remove electrical power from the isolation valve and the directional control valve solenoids.
Isolation Valve Switch The isolation valve switch is a micro switch mounted near the hinge point of the thrust reverse lever.
The switch is activated by a contoured surface at the hinge of the lever. The switch closes at any time the thrust reverse lever is lifted more than 10 degrees.
The switch is activated by a contoured surface on the switch cam via a follower and roller assembly. The switch closes and energizes the DCV any time the thrust reverse lever is lifted more than 29 degrees.
The target elements for the switch sensors are located on the translating sleeve. The sensors are adjusted to close when the reverser sleeve moves from the fully stowed position.
The stow relay is energized to complete an electrical circuit to the isolation valve. Since the reverser hydraulic power must remain available until the reverser is fully stowed during the stow cycle, a 5 second time delay following the sensed reverser stowed position is incorporated in the Proximity Switch Electronic Unit PSEU logic for the restow circuit.
System Separation The electrical circuit controlling the left engine thrust reverser is separated from the right engine. Separate power sources, circuit breakers, switches, wires, and relays through to separate isolation valves are used.
The individual reverser wire bundles are routed separately from each other. The auto-restow proximity sensors are connected to separate sections of the proximity switch electronic unit PSEU.
The control circuits to the HIV and DCV solenoids are electrically separated from the indication circuit on each engine. Proximity Sensor The auto-restow proximity sensors are excited by an electronic circuit in the PSEU mounted in the electrical rack.
The circuit and power source for the left thrust reverser restow sensors are separate from that of the right engine reverser.
Reverser unlock is indicated by "REV" in amber color. In full deploy "REV" changes to green. A two-second time delay is used with this isolation valve indication to remove nuisance warnings.
Reverser Unlocked Indication The reverser unlocked indication is activated by either of two proximity switches located one on each lock housing of the center actuators.
The "REV" amber indication occurs anytime either lock is unlocked. Full Reverse Indication The full reverse indication is controlled by two proximity switches which are connected so that the "REV" green indication occurs only when both reverser halves reach the fully deployed position.
In the event that amber and green are signalled simultaneously, the amber signal prevails. L R REV ISLN VAL caution indicates that a malfunction exists that may result in a reverser deployment if the thrust reverse lever is lifted in flight, or that on reverser may not deploy when commanded on the ground.
The indication is required because the pilot may not be able to detect the interlock failure to block thrust lever motion during normal thrust reverser deployment.
A status message will be sent to EICAS alerting the crew of the lack of interlock for the landing aid the next dispatch.
System Separation The electronic circuits operating the proximity switches and reverser indication are located in the proximity switch electronic unit module PSEU mounted in the electronic rack.
Complete separation is maintained between the left and right engine circuits with separate power sources, circuit breakers, wire, and relays.
Power which is generated by the HMG is transferred to the right and left thrust reversers via the standby and battery busses. If normal power is recovered during flight such that both main busses are energized, the HMG shuts down to allow normal system operation.
The main function of the EEC is the scheduling of fuel flow, stator vanes and bleed valves to control the thrust and performance of the engine as a function of the thrust lever position.
The EEC is configured as a dual channel system with independent inputs to and outputs from each channel. The reverser position is provided as an electrical signal to each EEC channel by two independent position sensing circuits containing linear variable differential transducers LVDT.
The LVDT electrical inputs for each channel are wired in parallel. These series connected LVDT outputs provide an indication of the average reverser sleeve position to each channel primary and secondary of the EEC, while maintaining electrical separation of the EEC channels.
Each EEC channel provides a discrete output which energizes the interlock actuator relay. Thrust Limiting Function This function compares the thrust commanded by the pilot TRA to the position of the thrust reverser sleeves.
The limiting function is incorporated to ensure that thrust is in the direction of the command. This function is invoked under two circumstances, the first occurs when the direction of commanded thrust has just changed and the reverser is in transit to the commanded position.
Mechanical interlocks are incorporated to prevent the pilot from commanding reverse thrust above idle until the thrust reverser is at a prescribed position.
Thrust limiting in the EEC, during normal operation, provides a second level of protection against high thrust in the uncommanded direction.
Thrust limiting will also be invoked in the case of an inadvertent departure of the thrust reverser from the commanded position. The EECs thrust limiting function provides an independent system to reduce the engines thrust until the sleeve position agrees with the TRA command.
July 3, In reply refer to: A through Honorable James B. All passengers and 10 crewmembers on board were fatally injured in the accident. The positions of the left engine thrust reverser actuators along with data from the electronic engine control EEC and the cockpit voice recorder CVR indicate that the left engine thrust reverse system deployed while the airplane was at approximately.
The preliminary evidence suggests that the reverse event was recognized by the flightcrew but that the airplane departed controlled flight, accelerated past the maximum operating velocity, and experienced an in-flight structural breakup.
Indications of an in-flight fire prior to the breakup have not been found. However, during the breakup, a large explosion was witnessed and burning debris fell to the ground.
The accident airplane was equipped with Pratt and Whitney PW series engines. The Boeing Airplane Company provides an electro-hydraulic thrust reverse system in these airplanes to redirect engine fan bypass airflow to aid in stopping the airplane on the ground.
The thrust reverse system contains logic switching devices that are designed to prevent in-flight deployment caused by a component failure or flightcrew action.
These engines also incorporate EEC devices. One function of the EEC is to reduce engine rpm to idle in the event of an inadvertent reverser deployment.
Although a reduction in reverse thrust is beneficial, it does not occur immediately because of the time delay while the engine spools down.
The thrust reverse system of the PW series engines installed in Boeing airplanes incorporates a hydraulic isolation valve HIV and a directional control valve DCV in the engine pylon.
The CVR revealed that the flightcrew observed the REV ISLN caution light illuminated about 9 minutes prior to the reverser deployment on the accident airplane and a crewmember observed that the light came on repeatedly.
The flightcrew discussed the Boeing Quick Reference Flight Handbook QRH information which states that if this caution light is illuminated, additional systems failures may cause inflight deployment.
The thrust reverse system is designed so that the HIV provides a safeguard against deployment caused by a DCV failure. The system is designed so that the HIV will open to provide pressure to the reverser system in flight to restow the thrust reverser if it is not fully closed.
The valve can also open when certain faults exist in the system logic. The HIV normally opens when the airplane lands and the reverse system is used.
A DCV failure might then be apparent when the translating cowl does not stow properly. The hydraulic thrust reverse actuators from the left engine of the accident airplane were found in the deployed position and no pre-existing faults were evident.
Hydraulic power for the actuators can come only through the DCV located in the pylon, which is a high vibration environment.
The left engine DCV has not been found and thus could not be examined for malfunction. It was located in the pylon near the point where the pylon separated, from the airplane.
However, a failure mode and effects analysis for the thrust reverser system has revealed failure modes in the DCV that could cause an uncommanded reverser deployment after an opening of the HIV.
The Safety Board has been provided with data from Boeing indicating that flight control has been demonstrated on the Boeing with one engine in the reverse idle position at knots IAS; however, the Board has been informed that such testing has not been performed at higher speeds or at higher engine thrust levels.
The Safety Board is concerned about the potential severity of airframe buffeting, aerodynamic lift loss, and subsequent yawing and rolling forces which may occur at the airspeed and engine thrust levels that existed when the reverser deployed in the accident flight.
The Safety Board is also concerned that Boeing flightcrew emergency procedures may not provide appropriate and timely guidance to avoid loss of flight path control in the event that the reversers deploy in flight.
Furthermore, consideration should be given to the development of emergency procedures which would include pulling the fire handle in the event that the reverser does deploy.
This would immediately remove fuel, and hydraulic and electrical power to the affected engine. The Safety Board also believes that flightcrews should be forewarned that an in-flight deployment of a thrust reverser may result in significant airplane buffeting, yawing, and rolling forces.
Conduct a certification review of the PW engine equipped Boeing airplane thrust reverser systems to evaluate electrical and mechanical anomalies and failure modes that can allow directional control valve pressure to be applied to the reverser EXTEND port.
The certification review should also determine the adequacy of the thrust reverser system safeguards when the hydraulic isolation valve is open to prevent uncommanded thrust reverser extensions.
Class I, Urgent Action A Amend the Boeing Flight Operations Manual on aircraft powered by the PW series engine to include in the section, "Reverser Isolation Caution Light," a warning that in-flight reverser deployment may result in severe airframe buffeting, yawing, and rolling forces.
Class I, Urgent Action A Pending completion of a certification review of the thrust reverser system, establish operational procedures to be followed upon illumination of the Reverse Isolation Caution Light REV ISLN that will enhance the controllability of the PW powered Boeing should a secondary failure result in the in-flight deployment of a thrust reverser.
Actions should be taken to achieve an appropriate. Also consider the inclusion of a procedure to pull the fire handle if this occurs.
In lieu of implementation of revised operational procedures, operators may be directed to deactivate thrust reversers until the certification review is completed and the reliability of the system can be adequately assured.
Class I, Urgent Action A Examine the certification basis of other model airplanes equipped with electrically or electro hydraulically actuated thrust reverse systems for appropriate safeguards to prevent inflight deployment of reversers and ensure that operating procedures are provided to enhance aircraft control in the event an of inadvertent in-flight reverser deployment.
To airworthiness authorities of countries having operators of Boeing Model , , , and airplanes. The FAA is cooperating in this investigation and, in addition, is reviewing thrust reverser certification philosophy and the design of current thrust reversers.
There will be future actions taken by the FAA to assure the safety of thrust reverser systems. The rules for thrust reverser certification assume that inflight reverser deployments will occur and they require that such deployments not result in an unsafe condition.
Traditionally, this has been demonstrated by tests conducted at relatively low speed and thrust conditions supported by analytical extrapolations to all flight conditions.
Service experience on many airplane models has included inflight deployments which were controllable and appeared to validate these certification procedures.
These procedures were applied to the certification effort, and indicated that an inflight reversal was a controllable event.
The recent accident calls these certification assumptions into question. It is possible that modern high bypass engines combined with more efficient thrust reversers have resulted in aircraft which require a new thrust reverser certification philosophy.
Inflight reversal, under certain flight conditions, may now be an event similar in magnitude to certain primary flight control failures which must be prevented to avoid loss of the aircraft.
The Boeing Company is in agreement with the need to upgrade the level of safety of thrust reverser systems, and has been cooperating with the FAA in a review of all of their thrust reverser installations.
This includes system design philosophy and system design details. This review, of course, began with the due to the recent accident.
Review of the thrust reverser installations in other Boeing airplanes has been proceeding and is now to a point where some future actions can be defined.
These actions include interim actions to assure the safety of thrust reversers and long term design changes and retrofit to bring thrust reverser systems up to safety level of primary flight controls.
This review, will discuss each Boeing airplane modal separately, and will present plans for both interim and final action. These are as follows: At present, all thrust reverser systems on these air planes are deactivated due to the issuance of airworthiness directive AD T, dated August 23, Boeing is at present studying several proposals for interim design changes, which would assure an increased level of safety for this thrust reverser system, thus permitting reactivation of these thrust reversers pending a final revision to the design.
Boeing intends to present their interim design change proposal to the FAA during the week of September 9, , and it is anticipated that service bulletins would be available for FAA review and approval during the week of September 23, If it is determined by the FAA that the proposal provides adequate safeguards, it is the intention of the FAA to mandate this design change by AD action, and permit reactivation of the affected thrust reverser systems.
When a final design change has been approved, it in turn will be mandated by ad action, it is anticipated that these design changes will reduce or eliminate the requirement for repetitive tests and inspections of the thrust reverser system.
At present, operation of these airplanes with active thrust reverser systems is permitted. It is anticipated that certain repetitive system tests and inspections will be mandated by AD action.
The service bulletins necessary for these tests and inspections have already bean approved by the FAA. In addition, the electrical wiring for these airplanes is being examined for adequacy with respect to system separation and hot short protection.
At the completion of this investigation, it is expected that a final design change will be generated, which will reduce or eliminate the requirement for repetitive tests and inspections of the thrust reverser system.
Since these thrust reverser systems employ mechanically actuated directional control valves, it is felt that they do not possess the same potential for inflight reversal as those systems listed above.
This assumption is further supported by a trouble free service history to date with respect to uncommanded inflight deployments. A comprehensive investigation of the hydraulic system is in progress, and any AD action will depend upon the results of this investigation.
When a final design change is approved, It will be mandated by AD action. As an interim action, the FAA is issuing an immediate adopted AD the week of September 9, , which mandates initial and follow-on thrust reverser electrical system checks and replacement of those DCV solenoid valves which are susceptible to the contamination failure.
A copy of the AD is included with this letter. The Boeing Company is currently evaluating long term thrust reverser system configuration changes which could be terminating action to all or part of the repetitive electrical system inspections.
Boeing Model series airplanes powered by Rolls Royce RB engines employ a different hydraulically actuated thrust reverser design. This system is not susceptible to the contamination failure cited in the AD.
Design changes are being developed by Boeing to improve the reverser system. Boeing Model engine thrust reverser systems: Any applicable system improvements identified for the systems will be required on the in the long term.
No immediate actions are being taken on the because aerodynamic differences between the and the twin-engine airplanes result in adequate controllability with a reverser deployed.
Nevertheless, the FAA believes and Boeing agrees that inflight thrust reversals are undesirable, and all design improvements identified for the thrust reverser system will also be incorporated on airplanes.
Boeing has indicated that it plans to release system check service bulletins for the thrust reverser systems in the near future.
The FAA recommends that any Boeing-provided system cheeks be performed, but there are no current plans to release airworthiness directives requiring the performance of the system checks contained in these service bulletins.
While there are no plans for FAA action as of this date, results of these investigations may require that steps be taken to incorporate features or activities consistent with actions taken on other models.
In closing, we would like to point out that, in addition to the above, you should be aware that the Transport Airplane Directorate is conducting a Design review of the thrust reverser installations on other large jet transports manufactured by McDonnell-Douglas, Airbus Industries, Lockheed, etc.
As a result of that review, design changes may be required in the future. We request that you ensure that this letter is made available to airline flight departments and to all pilots of the above Boeing airplanes, to keep them fully apprised of the progress of this investigation.
Sincerely, original signed by Leroy A. Comments of the accredited representative of the United States of America were brief; and incorporated in the Final Report.
Comments of the accredited representative of Austria are appended. Brief edit items were incorporated in the Final Report. Comments on airline maintenance activities and the calls for further testing and analysis of the effects of reverser deployment and reexamination of the Dispatch Deviation Guide are provided to enlighten the reader.
These items were not included in the Final Report or Recommendations. The Accredited Representative of the Republic of Austria, whilst agreeing that this report is a fair record of the investigation, regrets that the report was unable to form any conclusion as to the reason for the uncommanded thrust reverser deployment which was the fundamental cause of the accident.
Whilst acknowledging the modifications package developed for aircraft similar to the Lauda machine and the recommendation for design reviews of all other aircraft certificated for ground-use only reverser systems, the lack of knowledge about the aerodynamic effects of deployment at high Mach numbers and Indicated Air Speeds should not be allowed to persist.
Accordingly it is felt that the report should call for further analysis and testing to be accomplished on the effects of reverser deployment throughout the flight envelope on aircraft of similar configuration to the Boeing In addition, it is noted that the requirements of FAR I am concerned by the apparent lack of analysis of the Cockpit Voice Recorder, being the only continuous record of the accident event in the.
A repetitive EEC fault message that continues for some hours despite rectification actions is clearly not responding to these actions and yet could theoretically continue indefinitely as long as it does not manifest itself during the hour period allowed by the Dispatch Deviation Guide.
The following changes are proposed to be incorporated in the Final Report as they are written bold Italic , other comments should cause a more detailed explanation in the report:.
Page 2 Line Page 3 Line 7: The pilot-in-command, male, age 48, December 19, , valid until December 31, The co-pilot, First officer, male, 41 years of age, Civil Aviation of Austria issued April 24, Valid until October 24, Page 4 Line Post accident interrogation of the EEC non volatile memory, which dated to April 27 indicated a significantly higher number of similar messages occurred than were recorded in the documentations.
There was no radar recording of the accident flight available. Page 7 Line We feel the need to notify wind in velocity and direction in ft altitude steps under this headline or in the wreckage diagramme.
We feel the need to provide more evidence on the nature and the extent of the inflight fire or how the conclusion came up, that it occurred after the inflight break up.
Page 14 Line Page 15 Line 1: Page 16 Line 3: Page 19 Line 4: We feel the need to incorporate under this headline a sketch with breakup lines, sequences and reasons.