This report evaluates the crash of El Al Flight 1862, a Boeing 747 aircraft that crashed at Amsterdam on 4th October 1992 and with an investigators point of view, a better understanding as to why the crash took place and the factors that led to its crash would be obtained. Proposals by experts and the measures taken by the affected company would also be looked into.
The route for Flight 1862 was from John F.Kenndy International Airport; New York City, USA to Ben Gurion International Airport; Tel Aviv, Israel. It had to make a stop at Amsterdam Schiphol Airport; Amsterdam, Netherlands as more cargo needed to be loaded onto the plane and also for security checks. There were already problems with the aircraft system and engines during its flight from New York to Amsterdam Schiphol Airport. Because this repair was not done properly, proceeding on its journey towards Tel Aviv caused the plane to crash in a neighbourhood at Amsterdam, Bijlmermeer due to metal fatigue in the fuse pins which caused 2 Pratt and Whitney engines to break off from the right wing.
The aircraft took off at 1720 hours and crashed into a eleven floor apartment building in the Bijlmermeer, a suburb of Amsterdam at 1735 hours killing everyone on board and 43 others. In memorial to the event, the Bijlmer Memorial was built in Amsterdam
1. INTRODUCTION
Purpose
This report evaluates the crash of El Al Flight 1862 from an investigators and an engineer's point of view on the crash. The report also looks into the proposals by experts and measures taken by the affected company.
1.2 Background
In the past 15 months, aircrafts maintained by China Airlines, El Al and Evergreen has experienced at least 3 pylon failures that occurred during flight, one of which was a China Airline plane that crashed due to the separation of the pylons and engines No. 3 and No.4 (CBS Interactive Inc 2010).
El Al Airline has been a target area for shootings, hijackings and bomb attempts on numerous occasions. This is due to the Israeli and Palestinian conflict. El Al planes has been first hijacked in 1968 by Popular Front for the Liberation of Palestine (PELP) and the hijack lasted for 40days. On flight were 10 crew members and 38 passengers. Subsequent hijacked followed after the incident. One of which was on 26 December of that same year an El Al aircraft was hijacked killing an Israeli mechanic (CBS Interactive Inc 2010). Because of these subsequent attacks, El AL Israel Airlines have tightened their security and imposed measures to all passengers taking its flight. One of the measures includes passengers reporting time to be 3 hours before flight to make time for the extra screening process that would follow. At check-in counters the El Al's security officials would questions the passengers on their purpose of travel and their own personal background. However, these information are not recorded. On board, there is at least one air marshal; security officers who are trained in combat on each passenger flight (Wikidot 2010).
They now hold a reputation as the world's most tightly guarded passenger carrier (CBS Interactive Inc 2010).
1.3 Method Of Investigation
Data of this report was taken from Internet websites that relates the causes of the crash and other relevant information related to its crash. Other information was also taken from Peter R. March., 2008. The Boeing 747 story. It was also based upon a documentary series entitled "Air Crash Investigation" on the National Geographic Channel.
Scope Of Investigation
This report will cover aspects of the plane before and after its take off and also what happened on flight minutes before the crash and the reason why the aircraft crash due to structural failure. It will also cover the different problems faced such as communication failure between the Air Traffic Control (ATC) and the crew onboard during the crisis, and the control systems. Lastly, this report would be touching on various ways to improve and hopefully prevent a similar crash or problem in future.
PRE-FLIGHT
2.1 Aircraft Information
The El Al flight 1862 is operated by the Israel airlines. It is a Boeing 747 freighter; type 258F and was manufactured by Boeing Commercial Airplane Company in 1979. The aircraft uses 4 Pratt and Whitney high bypass ratio turbo fan engines. The last inspection of the midspar fuse pins of the pylon no.3 was on 17 June, 1992. Maintenance was carried out in correlation to the El Al maintenance program (Raad voor de Luchtvaart 1994).
The aircraft has a gross weight of 338.3 metric tons and has accumulated 45, 746 flight hours and 10,107 flight cycles in total. The aircraft would then have had 257 flight cycles until the accident. On October 4 1992, The aircraft carried a total of 4 occupants; pilot and the co-pilot, a flight engineer and a passenger. It departed from John F. Kennedy Int' Airport, New York City, USA and made a stopover at Amsterdam Schiphol International Airport, Amsterdam, Netherlands and had its destination set towards Tel Aviv's Ben Gurion International Airport, Israel (Aviation Safety Network Flight Safety 2006).
Checks Performed Before Take-Off
Before its schedule flight to Tel Aviv from New York, the Boeing 747-258F stopped at Schiphol at 1431 hours. It was refuelled and loaded with cargo. During its flight to Schiphol, there were already issues with the planes system. These included fluctuations in speed regulators and voltages of engine number 3 and its shortwave radio not being able to function properly. Repairs were done provisionally before take off (Cockpit Voice Recorder Database 2010).
The aircraft also underwent security checks as the airline was frequently targeted by hijackers and bombers. However, the flights cargo included dangerous armoury and gasses. These included depleted uranium and nerve-gas Sarin, that was ordered by Israel to test masks and filters that were designed to protect against chemical agents (Joel Greenberg 1998).
3. MID-FLIGHT
3.1 Structural Failure
Flight Controls
Primary controls of an aircraft would include ailerons, elevators and rudders. These are used to control yawing, rolling and pitching. Additional controls would consist of trailing and leading edge flaps, spoilers, and adjustable horizontal stabilisers. These are powered hydraulically, pneumatically or electrically. Spoilers are hydraulically powered from different hydraulic system. To stop the aircraft from yawing, rudder deflection is used. A lateral control deflection is used to stop the aircraft from rolling. During lateral control, spoilers are positioned by an output from the aileron's control system (Raad voor de Luchtvaart, 1994).
In total there are 4 hydraulic systems, each powering different primary and secondary controls of the aircraft.
While in flight, the extension of the inboard trailing edge flaps was successful because it was hydraulically powered by the number one hydraulic system. The extension of the outboard trailing edge flaps however was not successful and it did not extend because number four hydraulic system had already failed when no 4 engine was torn from the right wing (Cockpit Voice Recorder Database, 2010).
3.1.2 Hydraulic Systems And Engine
The hydraulic indicating system is located in the cockpit had soon failed too alongside with the flight control systems. There are only 4 separate main hydraulic system that are used for power requirements to flight controls and landing gear systems. Each main is connected to an engine and most of it's components are lecated in the pylon. Each hydraulic system differs from its reservoir capacity and has 2 pumps each installed in parallel to each other. These pumps can be controlled at the engineer station in the cockpit (Raad voor de Luchtvaart 1994).
The pylons on an aircraft function as an attachment that connects the engine to the main wing of the aircraft with the help of lugs. Fuse pins are fitted into the lug and it holds the engine to the pylons. They are designed to shear off and separate from the wing when faced under strong impact load or vibrations. In this accident however, there are 4 fuse pins that hold the engines to the main wing (Figure 1). Engine number 3 fractured due to corrosion fatigue and became unstable. Its fracture contributed to vibrations and heat on the fuse pins which caused one of fuse pins gave way. This let to additional stresses on the other 3 fuse pins which soon gave way too. Thus, engine number 3 was detached from the right wing due to fatigue failure of the pylon fuse pins. (Failure Knowledge Database 2010).
Problems Faced
3.2.2 Stability Of Plane And Landing
As there was a loss to the aircrafts leading edge flaps and damage to of the right wing, it thus limits the capability of that wing to generate lift. Therefore, the plane was unable to stabilise as the airflow affected the aircrafts angle of attack.
The pilot therefore suggested for an emergency landing
4. AFTER THE CRASH
Damage Due To The Crash
Aircraft
When they were cleaning up the site, engines no. 3 and 4 were retrieved back along with a few parts of the right wing's leading edge and several leading edge flaps. The leading edge tore off due to the impact of engine no. 3 that hit against engine no. 4 while breaking off. A pneumatic duct of the air system, which is located between engine no. 3 and 4
Death Rate And Buildings
The aircraft crashed almost at right angle into the 11 story apartment buildings.
Health Issues
In the following years after the accident, there were increasing reports on health complains from bystanders near the accident area. It was discovered that the aircraft was carrying depleted uranium and after clearance at the crash site, only 130kg of depleted uranium was discovered from its total of 282kg, therefore leaving 152kg missing. Tests were carried out to see if these health complaints were linked to the missing depleted uranium and it was later proven that these hazardous substances that were released from its burning cargo (Figure 1) contributed to the cause of these health issues from residents and by passers at the accident. One possible scenario would be that the depleted uranium had been partly oxidised in the fire and was released into the air, thus exposed to bystanders and residents (Journal of Hazardous Materials A76 2000).
It's cargo also included 50 gallons of dimethyl methylphosphonate which was said that it was enough to produce 594 pounds of Sarin (Joel Greenberg 1998). Upon clearing the crash site, contaminated soil was removed and replaced with clean soil. There were increased concentrations of kerosene in the lower soil layer and in the groundwater at the crash site. Another possible scenario would be that depleted uranium had been handled as normal trash, and dumped with the contaminated soil (Journal of Hazardous Materials A76 2000).
Due to this accident, not only the residents of the apartment, but also rescue officers and bypassers suffered effects of exposure to these substances (Failure Knowledge Database 2010).
Analysis Of The Accident
Referring to figure 1 above, flight 1862 took off from,Schiphol airport and proceeded on its schedule route to Tel Aviv. At point 1 and 2 was the area that the aircraft lost both its engine no. 3 and 4 as it dropped off from the wing into the sea. At point 4, the pilot requested to turn back for an emergency landing. From that point onwards, the crew lost control of the plane and went set it's on course. At point 7, flight 1862 crashed into the 11 storey apartment building. Investigators believed that after the two engine and pylon was detached from the right wing, the plane flew with a damaged right wing leading edge and flaps. They also lost roll and rudder control due to the missing outboard aileron and the partly functioning spoiler system (Joel Greenberg 1998). With the loss of Engine no. 3 and 4, Engine no. 1 and 2 were at high thrust settings to neutralised the speed decay which was believed to be caused by increased drag of a side slip and a possible extended leading edge flaps (Raad voor de Luchtvaart 1994).
Inspection was done after the incident using various macroscopic and microscopic technologies. The Netherlands Aviation Safety Board had concluded the lug and fuse pins were overloaded and this caused it to fail by fatigue (R.J.H Wanhill and A. Oldersama 1997)
Measures Taken
Upon crash Boeing carried out metallurgical stress analysis
