DC-10 United Flight UA232 Air Crash 'Engine Catastrophe'

Did the DC10 have too many safety problems?

United Airlines Flight 232 was a scheduled flight from Stapleton International Airport in Denver, Colorado, to O'Hare International Airport in Chicago. On July 19, 1989, the DC-10 (registered N1819U) operating the route crash-landed in Sioux City, Iowa, after suffering catastrophic failure of its tail-mounted engine, which led to the loss of all flight controls. Of the 296 people on board, 111 died in the accident while 185 survived. Despite the deaths, the accident is considered a prime example of successful crew resource management due to the manner in which the flight crew handled the emergency, and the high number of survivors considering that the airplane was landed without conventional control. The flight crew became well known as a result of their actions, in particular the captain, Alfred C. Haynes, and a DC-10 instructor on board who offered his assistance, Dennis E. Fitch.

The uncontained manner in which the engine failed resulted in high-speed shrapnel being hurled from the engine; this shrapnel penetrated the hydraulic lines of all three independent hydraulic systems on board the aircraft, which rapidly lost their hydraulic fluid. As the flight controls on the DC-10 are hydraulically powered, the flight crew lost their ability to operate nearly all of them. Despite these losses, the crew were able to attain and then maintain limited control by using the only systems still workable: the two remaining engines. By utilizing each engine independently, the crew made rough steering adjustments, and by using the engines together they were able to roughly adjust altitude. The crew guided the crippled jet to Sioux Gateway Airport and lined it up for landing on one of the runways. Without the use of flaps and slats, they were unable to slow down for landing, and were forced to attempt landing at a very high airspeed. The aircraft also landed at an extremely high rate of descent due to the inability to flare (reduce the rate of descent prior to touch down by increasing pitch). As a result, upon touchdown the aircraft broke apart, rolled over and caught fire. The largest section came to rest in a cornfield next to the runway. Despite the ferocity of the accident, 185 (62.5%) passengers and crew survived owing to a variety of factors including the relatively controlled manner of the crash and the early notification of emergency services.

The cause of the engine failure was traced back to a manufacturing defect in the fan disk, which had microscopic cracks due to impurities. The cracking was present during maintenance inspections and should have been detected by maintenance personnel, revealing shortcomings in the maintenance processes.

The accident had a strong impact on the industry. DC-10s were modified with hydraulic fuses to prevent catastrophic loss of hydraulic fluid should a similar failure occur again. These modifications were also included in the DC-10's direct successor, the MD-11. Research has been conducted to see whether computers might be able to control aircraft using the engines alone, improving on what humans can do unaided.

Japan Airlines JAL Flight 123 'Explosive Decompression'

Japan Airlines Flight 123 was a scheduled domestic Japan Airlines passenger flight from Haneda Airport (Tokyo International Airport) to Osaka International Airport, Japan. On Monday, August 12, 1985, a Boeing 747SR operating this route suffered mechanical failure 12 minutes into the flight and, 32 minutes later, crashed into two ridges of Mount Takamagahara in Ueno, Gunma Prefecture, 100 kilometres (62 miles) from Tokyo. The crash site was on Osutaka Ridge (御巣鷹の尾根 Osutaka-no-One), near Mount Osutaka. All 15 crew members and 505 of the 509 passengers on board died.

It is the deadliest single-aircraft accident in history, the deadliest aviation accident to occur on Japanese soil, and the second-deadliest 747 air disaster and deadliest accident behind the 1977 Tenerife airport disaster. The fatalities added to August 1985 being commercial aviation's single deadliest month for passenger and crew deaths, part of the single deadliest such year, coming just ten days after the crash of Delta Air Lines Flight 191 killing 137 people and ten days before a fire on board British Airtours Flight 28M killed a further 55 people.

Flight 123 pushed back from gate 18 at 6:04 pm and took off from Runway 15L at Tokyo International Airport (commonly referred to as Haneda Airport) in Ōta, Tokyo, Japan, at 6:12 pm, 12 minutes behind schedule. About 12 minutes after takeoff, at near cruising altitude over Sagami Bay, the aircraft's aft pressure bulkhead tore open due to a preexisting defect, stemming from a panel that had been incorrectly repaired after a tailstrike accident years earlier. This caused an explosive decompression, causing pressurized air to rush out of the cabin and bring down the ceiling around the rear lavatories. The air then blew the vertical stabilizer off the aircraft, severing all four hydraulic lines. A photograph taken from the ground some time later confirmed that the vertical stabilizer was missing. Loss of cabin pressure at high altitude caused a lack of oxygen throughout; emergency oxygen masks for passengers were deployed. Flight attendants, including one off-duty, administered oxygen to various passengers using hand-held tanks.

This photograph shows the plane as it looked after explosive decompression. The vertical stabilizer is missing (circled in red).
The pilots set their transponder to broadcast a distress signal. Tokyo Area Control Center directed the aircraft to descend and follow emergency landing vectors. Because of control problems, Capt. Takahama requested a vector to Haneda, knowing it was ideally suited for a 747 in case of an emergency.

Hydraulic fluid completely drained away through the rupture. With total loss of hydraulic control and non-functional control surfaces, plus the lack of stabilizing influence from the vertical stabilizer, the aircraft began up and down oscillation in a phugoid cycle. In response, pilots exerted efforts to establish stability using differential engine thrust. Further measures to exert control, such as lowering the landing gear and flaps, interfered with control by throttle; the aircrew's ability to control the aircraft deteriorated.

Upon descending to 13,500 feet (4100 m), the pilots reported an uncontrollable aircraft. Heading over the Izu Peninsula the pilots turned towards the Pacific Ocean, then back towards the shore; they descended below 7,000 feet (2100 m) before returning to a climb. The aircraft reached 13,000 feet (4000 m) before entering an uncontrollable descent into the mountains and disappearing from radar at 6:56 pm at 6,800 feet (2100 m). In the final moments, the wing clipped a mountain ridge. During a subsequent rapid plunge, the plane then slammed into a second ridge, then flipped and landed on its back. The aircraft's crash point, at an elevation of 1,565 metres (5,135 ft), is located in Sector 76, State Forest, 3577 Aza Hontani, Ouaza Narahara, Ueno Village, Tano District, Gunma Prefecture. The east-west ridge is about 2.5 kilometres (8,200 ft) north north west of Mount Mikuni. Ed Magnuson of Time magazine said that the area where the aircraft crashed was referred to as the "Tibet" of Gunma Prefecture.

The elapsed time from the bulkhead explosion to when the plane hit the mountain was estimated at 32 minutes – long enough for some passengers to write farewells to their families. Subsequent simulator re-enactments with the mechanical failures suffered by the crashed plane failed to produce a better solution, or outcome; despite best efforts, none of the four flight crews in the simulations kept the plane aloft for as long as the 32 minutes achieved by the actual crew.

Hidden Danger - United Airlines Flight 585

United Airlines Flight 585 was a scheduled passenger flight from the now-decommissioned Stapleton International Airport in Denver to Colorado Springs, Colorado.

On March 3, 1991, the Boeing 737-291 operating the flight, registered N999UA[1] (previously N7356F with Frontier Airlines), carrying 20 passengers plus a flight crew of 5, crashed while on final approach to runway 35 at Colorado Springs Municipal Airport. There were no survivors

USAir Flight 427 was a scheduled flight from Chicago's O'Hare International Airport to Pittsburgh International Airport, with a final destination of West Palm Beach, Florida. The flight crashed on Thursday, September 8, 1994, killing all 132 on board. The Boeing 737-3B7 flying the route, registered N513AU, and previously registered as N382AU, was approaching runway 28R of Pittsburgh International Airport, located in Findlay Township, Allegheny County, Pennsylvania, which was at the time the largest hub for the airline.

Eastwind Airlines Flight 517 was a scheduled domestic passenger flight from Trenton-Mercer Airport in Trenton, New Jersey to Richmond International Airport in Richmond, Virginia. On June 9, 1996 the crew of the Boeing 737-200 operating the flight lost rudder control but was able to land successfully. Only one flight attendant suffered minor injuries. No damage occurred to the aircraft as a result of the incident.

The flight crew of the Boeing 737-200, Captain Brian Bishop and First Officer Spencer Griffin, experienced loss of rudder control while on approach to Richmond. The airplane's airspeed was about 250 knots (460 km/h; 290 mph) and it was flying at an altitude of about 4,000 feet (1,200 m) MSL at the time of the incident. The crew experienced unexpected movement of the rudder, causing the airplane to roll to the right. They applied opposite aileron input to keep the plane from rolling over and thirty seconds later the plane righted itself back to leveled flight. As the crew performed the emergency checklist, the plane again rolled over to the right. After another thirty seconds, the plane snapped back to leveled flight. The crew declared an emergency and landed safely in Richmond. The resulting investigation of this incident would help to establish the cause of two earlier accidents involving 737's which had occurred several years prior, United Airlines Flight 585 (March 3, 1991) and USAir Flight 427 (September 8, 1994).

It was later reported that the airplane previously had problems with uncommanded rudder deflections. These reports consisted of "rudder bumps" during departure and a lack of proper trim.[1]

British Midland Flight 92 'Motorway Plane Crash'

Random Fact: The 'brace position' used today was introduced after examination of passenger injuries from this accident!

The Kegworth air disaster occurred on 8 January 1989 when British Midland Flight 92, a Boeing 737-400, crashed onto the embankment of the M1 motorway near Kegworth, Leicestershire, UK. The aircraft was attempting to conduct an emergency landing at East Midlands Airport. Of the 126 people aboard, 47 died and 74, including seven members of the flight crew, sustained serious injuries.

After taking off from Heathrow at 7:52 pm, Flight BD 092 was climbing through 28,300 feet to reach its cruising altitude of 35,000 feet when a blade detached from the fan of the port (left) engine. While the pilots did not know the source of the problem, a pounding noise was suddenly heard, accompanied by severe vibrations. In addition, smoke poured into the cabin through the ventilation system and a burning smell entered the plane. Several passengers sitting near the rear of the plane noticed smoke and sparks coming from the left engine.

The flight was diverted to nearby East Midlands Airport at the suggestion of British Midland Airways Operations.

After the initial blade fracture, Captain Kevin Hunt had disengaged the plane's autopilot. When Hunt asked First Officer David McClelland which engine was malfunctioning, McClelland replied: "It's the le... No, the right one". In previous versions of the 737, the left air conditioning pack, fed with compressor bleed air from the left (number 1) engine, supplied air to the flight deck, while the right air conditioning pack, fed from the right (number 2) engine supplied air to the cabin. On the 737-400 this division of air is blurred; the left pack feeds the flight deck but also feeds the aft cabin zone, while the right feeds the forward cabin. The pilots had been used to the older version of the aircraft and did not realise that this aircraft (which had only been flown by British Midland for 520 hours over a two-month period) was different. The smoke in the cabin led them to assume the fault was in the right engine. The pilots throttled back the working right engine instead of the malfunctioning left engine. They had no way of visually checking the engines from the cockpit, and the cabin crew—who did not hear the commander refer to the right hand engine in his cabin address—did not inform them that smoke and flames had been seen from the left engine.

When the pilots completely shut down the right engine, they could no longer smell the smoke, which led them to believe that they had correctly dealt with the problem. As it turned out, this was a coincidence: when the autothrottle was disengaged to shut down the right engine, the fuel flow to the left engine was reduced, and the excess fuel which had been igniting in the jet exhaust disappeared; therefore, the ongoing damage was reduced, the smoke smell ceased, and the vibration reduced, although it would still have been visible on cockpit instruments.

During the final approach to the East Midlands Airport, more fuel was pumped into the damaged engine to maintain speed, which caused it to cease operating entirely and burst into flames. The flight crew attempted to restart the right engine by windmilling, using the air flowing through the engine to rotate the turbine blades and start the engine, but the aircraft was by now flying at 185 km/h, too slow for this. Just before crossing the M1 motorway, the tail struck the ground and the aircraft bounced back into the air and over the motorway, knocking down trees and a lamp post before crashing on the far embankment and breaking into three sections approximately 519yd (1/4-mile or 475 metres) short from the active runway's paved surface and approximately 689yd (1/3-mile or 630 metres) from its threshold. Remarkably, there were no vehicles on that part of the motorway at the moment of the crash.

EL AL Israel Flight 1862 'Amsterdam Crash'

On 4 October 1992, El Al Flight 1862, a Boeing 747 cargo plane of the state-run Israeli airline El Al, crashed into the Groeneveen and Klein-Kruitberg flats in the Bijlmermeer (colloquially "Bijlmer") neighbourhood (part of Amsterdam-Zuidoost) of Amsterdam, the Netherlands. For the location in the Bijlmermeer, the crash is known in Dutch as the "Bijlmerramp" (or Bijlmer disaster). A total of 43 people were killed, including the plane's crew of three, a non-revenue passenger in a jump seat, and 39 people on the ground. Many more were injured. This accident remains the deadliest aviation accident to ever occur in The Netherlands (though not the deadliest accident involving Dutch people, a distinction that belongs to the Tenerife airport disaster). The disaster was made worse by the large fire that resulted from the crash.

Flight 1862 was scheduled to depart at 5:30 pm, but the flight was delayed until 6:20 pm. At 6:22 pm, Flight 1862 departed from runway 01L on a northerly heading. Once airborne, the aircraft turned to the right on its departure route. Soon after the turn, at 6:27 pm, above the Gooimeer, a lake near Amsterdam, a sharp bang was heard while the aircraft was climbing through 1950 meters (6500 feet). The bang was the result of the two fuse pins attaching engine three to the right wing failing due to microscopic fatigue cracks. The engine separated from the right wing of the aircraft, shot forward, damaged the wing flaps, then fell back and struck engine number four, tearing it from the wing. The two engines fell away from the aircraft, also ripping out a 9-meter (30-foot) stretch of the wing's leading edge. The loud noise attracted the attention of some pleasure boaters on Gooimeer. The boaters notified the Netherlands Coastguard of two objects they had seen falling from the sky. One boater, a police officer, said he initially thought the two falling objects were parachutists, but as they fell closer he could see they were both plane engines.

The captain made a mayday call to air traffic control (ATC) and indicated that he wanted to return to Schiphol. At 6:28:45 pm, the captain reported: "El Al 1862, lost number three and number four engine, number three and number four engine." ATC and the flight crew did not yet grasp the severity of the situation. Although the flight crew knew they had lost power from the engines, they did not see that the engines had completely broken off and that the wing had been damaged. The outboard engine on the wing of a 747 is visible from the cockpit only with difficulty and the inboard engine on the wing is not visible at all. Given the choices that the captain and crew made following the loss of engine power, the Dutch parliamentary inquiry commission that later studied the crash concluded that the crew did not know that both engines had broken away from the right wing.

At 6:35:25 pm, the first officer radioed to ATC: "Going down, 1862, going down, going down, copied, going down." In the background, the captain was heard instructing the first officer in Hebrew to raise the flaps and lower the landing gear.

DHL Flight 611 Deadly Mid Air Crash 'The Überlingen Disaster'

Bashkirian Airlines Flight 2937 was a chartered flight from Moscow, Russia to Barcelona, Spain, carrying sixty passengers and nine crew. Forty-five of the passengers were Russian schoolchildren from the city of Ufa in Bashkortostan on a school trip organized by the local UNESCO committee to the Costa Daurada area of Spain. Most of the parents of the children were high-ranking officials in Bashkortostan. One of the fathers was the head of the local UNESCO committee.

The aircraft, a Tupolev Tu-154M registered as RA-85816, was piloted by an experienced Russian crew: 52-year-old Captain Alexander Mihailovich Gross (Александр Михайлович Гросс) and 40-year-old First Officer Oleg Pavlovich Grigoriev (Олег Павлович Григорьев). The captain had more than 12,000 flight hours to his credit. Grigoriev, the chief pilot of Bashkirian Airlines, had 8,500 hours of flying experience and his task was to evaluate Captain Gross's performance throughout the flight. 41-year-old Murat Ahatovich Itkulov (Мурат Ахатович Иткулов), a seasoned pilot with close to 7,900 flight hours who was normally the first officer, did not officially serve on duty due to the captain's assessment. 50-year-old Sergei Kharlov, a flight navigator with approximately 13,000 flight hours, and 37-year-old Flight Engineer Oleg Valeev, who had almost 4,200 flight hours, joined the three pilots in the cockpit.

DHL Flight 611, a Boeing 757-23APF cargo aircraft registered as A9C-DHL, had originated in Bahrain and was being flown by two Bahrain-based pilots, 47-year-old British Captain Paul Phillips and 34-year-old Canadian First Officer Brant Campioni. Both pilots were very experienced – the captain had clocked close to 12,000 flight hours and the first officer had accumulated more than 6,600 flight hours. At the time of the accident, the aircraft was en route from Bergamo, Italy to Brussels, Belgium.

The two aircraft were flying at flight level 360 (36,000 feet, 10,973 m) on a collision course. Despite being just inside the German border, the airspace was controlled from Zürich, Switzerland, by the private Swiss airspace control company Skyguide. The only air traffic controller handling the airspace, Peter Nielsen, was working two workstations at the same time. He did not realize the problem in time and thus failed to keep the aircraft at a safe distance from each other. Only less than a minute before the accident did he realize the danger and contacted Flight 2937, instructing the pilot to descend by a thousand feet to avoid collision with crossing traffic (Flight 611). Seconds after the Russian crew initiated the descent, however, their traffic collision avoidance system (TCAS) instructed them to climb, while at about the same time the TCAS on Flight 611 instructed the pilots of that aircraft to descend. Had both aircraft followed those automated instructions, the collision would not have occurred.

Flight 611's pilots on the Boeing jet followed the TCAS instructions and initiated a descent, but could not immediately inform Nielsen because the controller was dealing with Flight 2937. About eight seconds before the collision, Flight 611's descent rate was about 2,400 feet per minute (12 m/s), not as rapid as the 2,500 to 3,000 ft/min (13 to 15 m/s) range advised by TCAS. Having already commenced his descent, as instructed by the controller, the pilot on the Tupolev disregarded the TCAS instruction to climb, thus both planes were now descending.

Unaware of the TCAS-issued alerts, Nielsen repeated his instruction to Flight 2937 to descend, giving the Tupolev crew incorrect information as to the position of the DHL plane. Maintenance work was being carried out on the main radar system, which meant that the controllers were forced to use a slower system.

The aircraft collided at almost a right angle at an altitude of 34,890 feet (10,630 m), with the Boeing's vertical stabilizer slicing completely through Flight 2937's fuselage just ahead of the Tupolev's wings. The Tupolev exploded and broke into several pieces, scattering wreckage over a wide area. The nose section of the aircraft fell vertically, while the tail section with the engines continued, stalled, and fell. The crippled Boeing, now with 80% of its vertical stabilizer lost, struggled for a further seven kilometers (four miles) before crashing into a wooded area close to the village of Taisersdorf at a 70-degree downward angle. Each engine ended up several hundred metres away from the main wreckage, and the tail section was torn from the fuselage by trees just before impact. All 69 people on the Tupolev, and the two on board the Boeing, died.

American Airlines Flight 587 'Disaster over New York'

American Airlines Flight 587 was a regularly scheduled passenger flight from John F. Kennedy International Airport in New York City to Santo Domingo's Las Américas International Airport in the Dominican Republic. On November 12, 2001, the Airbus A300-600 flying the route crashed into the Belle Harbor neighborhood of Queens, a borough of New York City, shortly after takeoff. All 260 people on board the flight were killed, along with five people on the ground. It is the second-deadliest aviation incident involving an Airbus A300, after Iran Air Flight 655 and the second-deadliest aviation incident to occur on U.S. soil, after American Airlines Flight 191. To date, no single-airplane crash incident that was ruled accidental and not criminal since then has surpassed that death toll, though before 2001 there had been deadlier incidents of this type.

The location of the accident and the fact that it took place two months and one day after the September 11 attacks on the World Trade Center in Manhattan initially spawned fears of another terrorist attack. However, terrorism was officially ruled out as the cause by the National Transportation Safety Board, which instead attributed the disaster to the first officer's overuse of rudder controls in response to wake turbulence or jet wash from a Japan Airlines Boeing 747-400 that took off minutes before it. According to the NTSB, this aggressive use of the rudder controls by the co-pilot caused the vertical stabilizer to snap off the plane. The plane's two engines also separated from the aircraft before it hit the ground.

The A300-600 took off immediately after a Japan Airlines Boeing 747-400 on the same runway. It flew into the larger jet's wake, an area of turbulent air. The first officer attempted to stabilize the aircraft with alternating aggressive rudder inputs. The strength of the air flowing against the moving rudder stressed the aircraft's vertical stabilizer, and eventually snapped it off entirely, causing the aircraft to lose control and crash. The National Transportation Safety Board (NTSB) concluded that the enormous stress on the rudder was due to the first officer's "unnecessary and excessive" rudder inputs, and not the wake turbulence caused by the 747. The NTSB further stated "if the first officer had stopped making additional inputs, the aircraft would have stabilized". Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 sensitive rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Training Program.

The manner in which the vertical stabilizer separated concerned investigators. The vertical stabilizer is connected to the fuselage with six attaching points. Each point has two sets of attachment lugs, one made of composite material, another of aluminum, all connected by a titanium bolt; damage analysis showed that the bolts and aluminum lugs were intact, but not the composite lugs. This, coupled with two events earlier in the life of the aircraft, namely delamination in part of the vertical stabilizer prior to its delivery from Airbus's Toulouse factory, and an encounter with heavy turbulence in 1994, caused investigators to examine the use of composites. The possibility that the composite materials might not be as strong as previously supposed was a cause of concern because they are used in other areas of the plane, including the engine mounting and the wings. Tests carried out on the vertical stabilizers from the accident aircraft, and from another similar aircraft, found that the strength of the composite material had not been compromised, and the NTSB concluded that the material had failed because it had been stressed beyond its design limit, despite ten previous recorded incidents where A300 tail fins had been stressed beyond their design limitation in which none resulted in the separation of the vertical stabilizer in-flight.

The official NTSB report of October 26, 2004, stated that the cause of the crash was the overuse of the rudder to counter wake turbulence.

The crash was witnessed by hundreds of people, 349 of whom gave accounts of what they saw to the NTSB. About half (52%) reported a fire or explosion before the plane hit the ground. Others stated that they saw a wing detach from the aircraft, when in fact it was the vertical stabilizer. Some witnesses reported seeing one of the engines burst into flames and break off the plane, and others reported hearing a loud sound like a sonic boom.

After the crash, Floyd Bennett Field's empty hangars were used as a makeshift morgue for the identification of crash victims.