aircraft maintenance
What causes abnormal aircraft maintenance

Maintenance of aircraft and fatal mistake.


In January 2000, the jet airliner, owned by "Alaska Airlines"88 with passengers and crew on board crashed and fell into the water. Negligence and irresponsibility led to a terrible catastrophe. When one of the engineers said the repairs are not enough quality, he was suspended from work. The investigation revealed the glaring facts of neglect of duty. It showed that a number of unforgivable mistakes led to the tragedy, which may again be repeated. Next you will see the consequences of improper aircraft maintenance.


Puerto Vallarta - known Mexican resort on the Pacific coast. Most of the passengers of the flight back to 261 rest. They are tuned to the long flight to San Francisco. At the helm of the aircraft were experienced pilots. Captain - Ted Thompson and co-pilot - William Tang. They have flown thousands of hours MD-83 and we knew very well this car. MD-83 was very reliable, well-controlled aircraft.


January 31 2000 years 261 when the board was preparing to take off, the pilots did not anticipate that the tail of the aircraft lurking danger of death. Shortly after takeoff, the captain and co-pilot felt that the car is not right. Jammed horizontal stabilizer, located in the tail of the plane. The pilots were trying to figure out what to do next.


The stabilizer on the plane MD-83 is a horizontal plane 12 meters wide. There, in the rear, were two of the elevator. With the stabilizer and elevators to adjust the angle of the flight. The stabilizer jammed, and the pilots thought it was due to the motor that moved the stabilizer up and down. They did not know that the situation is much more serious. The pilots thought that they themselves deal with this problem.


Expert: They are not alerted by the fact that the stabilizer jammed. They thought it was a small problem and concern for no particular reason.


The crew believed that the regulator did not act because the jack was not working. To bring it into effect, the pilots immediately tried to use two switches, one of which was at the wheel and the other on the control panel. Without the stabilizer it was impossible to align the plane. He always pulled to the ground. At the height of 8500 meters pilots disengage the autopilot and fly a plane manually. They had to pull forces from all over the helm to align the plane. It took a huge physical effort. 7 minutes later they scored the flight height - 10000 meters. Flying over the coast, they are connected with the repair service of its airlines. Unfortunately, the repair service does not able to help them.


Expert: Pilots acted blindly. They pulled all the switches, which are responsible for the stabilizer, and hoped that it will work.


Pilots concerned about whether they can land safely. It was not known how to behave in a plane in the next second. All the flight crew flew the plane manually. Airliner permanently bury the nose, and they descended to an altitude of 6100 meters. The crew made another attempt to activate the stabilizer. To this end, they have set in motion just two of the motor. However, the next moment they heard a click, and the plane suddenly dropped his nose and went into a steep dive. Almost a minute pilots tried to keep the wheel and align the plane. MD-83 550 dived at speeds of km / h. Pilots from all the forces pulling the wheel itself, and they were able to time raise the nose. To keep the aircraft in a horizontal position, the pilots decided to use the elevator. This mobile panel located in the rear, which is connected by wires to the controls. The pilots pulled them over. The fate of the aircraft depended on the strength of their muscles. Inside, immediately rose panic. Passengers do not know what happened to the plane. Meanwhile, the crew tried to adjust the speed of the aircraft to be able to land.


Expert: They were very experienced pilots, but the situation is more complicated. It became clear that a disaster could happen.


The plane was heading to Los Angeles to make an emergency landing there. For some time, the situation has stabilized, and the pilots asked the manager to give them the space above and below the plane. They wanted to find out the cause of the failure.


aircraft maintenance 1


The pilots realized that they were faced with a very serious problem. The situation is worse because they had to decline, but the reaction of the airplane on their actions were unpredictable. They again contacted the ground services, and asked for help.


Judge: Well, when it is possible to contact with the ground by the technical service which has the necessary references. In addition, the technical service to obtain advice from the manufacturer. However, they are not always able to offer any assistance.


Unfortunately, the technical service failed to realize the danger of the situation. The pilots did not get them any practical assistance. In fact, they were left alone with a defective stabilizer of the aircraft.


The pilots tried to reassure the terrified passengers and informed them that during 20-30 minutes they landed in Los Angeles. Unfortunately, this did not happen. The crisis that began on board ended the terrible disaster.


The crew tried to play it safe. The pilots asked the controller to give them the way to the Gulf. They were to remain above water until they would take control of the management. Again and again they pulled stabilizer switches, hoping that it will work. But all their attempts to rectify the situation were unsuccessful.


261 board was preparing to land in Los Angeles as in the tail of something knocked. The plane's nose dropped again strongly. They began to fall from the height of the stone 5500 meters. The aircraft overturned. He was thrown from side to side, but the pilots still trying to take it out of pique.


Expert: They led the plane even in an inverted position and believe that they will succeed.


            After seconds 60 261 terrible dive aboard crashed into the Pacific Ocean at the speed of 400 km / h.


            Aircraft MaintenanceSoon on the scene of the accident rescue helicopters arrived, but there was no one to save. The plane crashed into pieces. The crew and passengers were killed 88. Investigation of the disaster began immediately, but the wreckage lying at a depth of 200 meters.


Expert: During the operation of raising the wreckage, we used a special vessel equipped with scanning radars.


When the "black boxes" were found, the National Transportation Safety Committee (NTSB) investigation records began talks in the cockpit.


Expert: We immediately realized that the problem was in the tail section of the plane of the deceased. It was there and it was necessary to find the cause of this terrible disaster.


Airliner MD-83 at that time was in high demand. More than 2000 of such aircraft flew all over the world. The peculiarity of their design was that they had a T-shaped tail. The horizontal plane on the vertical stabilizer provided the balance of the aircraft in the air. A specific MD-83 model uses an automatic screw jack located in the tail. He moved the horizontal stabilizer up and down. When the stabilizer moved upwards, the nose of the plane fell. And when the stabilizer moved down, the nose of the plane rose. This device was very reliable.


What was the role of the jack screw length 70 centimeters tragedy Flight 261? We had to pick it up from the ocean floor.


Expert: We are very surprised when they inspected the wreckage. Jackscrew was threaded into the coupling. He was lying on his own. Coupling jackscrew and are spaced from each other. It is not clear how a jack which is to be screwed into the sleeve, turned away from it. We have also discovered that the thread inside the sleeve was nearly erased and its remnants are wound on the screw thread of the jack. It was more than enough.


Since the thread inside the sleeve has been erased, the jack to spin. Pilots could not understand what the problem. There was no answer in any book. It just never happened. Even when the pilots realized that the problem lay in the rear of the aircraft, they did not know what they need to do. The crew included two alternate engine jackHowever, all their efforts only aggravated the situation.


Expert: Their mistake was that they included both engines at once. And primary and secondary.


When the pilots included just two engine began to rotate jackscrew. However, he just wiped the remnants of thread, but does not affect the stabilizer. The plane was doomed. Under the influence of aerodynamic loads jack completely out of order. No one, even the most experienced pilot could not do anything in this situation. Locknut could not hold the jack in the seats. Some time later, she broke down.


Expert: When the lock nut is broken, the horizontal stabilizer completely out of order, and the aircraft became uncontrollable.


Without the stabilizer the nose sloped down, and soon they entered into a deadly peak. Pilots have nothing depended. Experts were absolutely sure, that a faulty screw jack It was the cause of the crash bead 261. Investigators asked the following question: why is it broken?


          aircraft maintenance 2Finding out the problem, the investigators noticed that the jack almost no lubrication. This fact is very guarded experts, and they reported it to the Aviation Administration. Those, in turn, ordered to check all aircraft MD-83. It made a startling discovery. It turned out that the company «Alaska Airlines» at 6 34 from aircraft that node was in the same condition as in the ship perished.


Expert: Lack of lubrication - That's the reason. That is what led to the fact that the screw thread has worn off.


            Thus, the simple lack of lubrication cost the lives of all the passengers of flight 261. Attention experts focused on how to carry out repair and maintenance work in the airline. Soon the scandalous facts were revealed.


Investigator: We talked to all the mechanics who worked in "Alaska Airlines". They said that they often had to write false reports on the work performed. In fact, they had not been served.


All the mechanics, said that authorities ignore their recommendations. In fact, the aircraft was sent to flight without a proper repair. «Alaska Airlines» has been a successful company, but crisis of the early 90-ies affected everyone. Then the management has reduced prices on airline tickets. But this situation is also reflected in the chartaircraft maintenance.


IlliterateAircraft Maintenance It led to the tragedy.


In October 1998, one of the airline's mechanics applied to the Aviation Administration complaining about the «Alaska Airlines». He described in detail the situation with the repair of aircraft. A year before the catastrophe «Alaska Airlines» raided check state. services. They seized documents of the company, which dealt with the repair of aircraft. However, serious punishment followed. The company was able to convince the inspection bodies that repair and aircraft maintenance were carried out properly. On the company was fined. And then disaster struck. As shown on the records of the deceased liner service, He already 2 years needed to replace a screw jack. This replacement has not been performed.


Experts continued to investigate the cause of the disaster voyage 261 and made some more discoveries. When the company lowered ticket prices, it has significantly increased the intervals between maintenance work. It was unacceptable, since each node and each item has a certain lifespan. Incorrect aircraft maintenance and led to the accident flight 261.


Judge: If the plane flies 600 hours without inspection - it is a lot. During this time, can wear away the grease and metal parts will wear. But if the range is 2000-2500 hours, as it was in "Alaska Airlines"- This will inevitably lead to disaster. It happened with the flight 261.


The NTSB's final report concluded that «Alaska Airlines» not promptly replaced the horizontal stabilizer jackscrew on the plane MD-83. In the pursuit of profit, the safety of passengers was in last place. Also, the investigation has revealed weaknesses in the structure of the aircraft. Faulty unit was the cause of death of all aircraft.


Relatives of the victims hope that the airlines and manufacturers to make the necessary findings and such tragedies will no longer be.


List of air crashes