4Airbus A380 report

Technical report regarding QF 32 incident 4th Nov 2010

Introduction

This report focuses on the incident which involved a Qantas Airlines: Airbus A380. The modern aircraft suffered an engine turbine failure.

Incident summary

The Qantas flight:Q32 was the continuation flight from UK to Australia. The flight which is outbound from Singapore suffered from an uncontained turbine failure in one of its Trent 900 engines. Starting from an engine failure, The objective of this report is to tailor the different events that took place during the trauma.

During its transit stay in Singapore there was refuel. The flight was again operated from Singapore to Sydney by another set of flight crews. However, the flight contained additional pilots who were on routine inspection on the commanding pilots. As scheduled the flight departed at 0900 normally. As the aircraft was relatively light, low thrust was used by the crew to take off. The aircraft has climbed exceeding 7,000 ft. At this stage the aircraft was above the Indonesian Island: Batam.

After which, a huge noise was heard two times. This was then followed by number of ECAM messages (Electronic Centralised Aircraft Monitor) system. During this it was concluded that the noise was heard from the Engine 2. The first message indicated that the ‘Engine 2 Turbine Overheat’. This required reducing the thrust to idle with time condition to about 30

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4seconds to reduce temperature. However, the message reconfigured to ‘Engine Fire’.The message kept oscillating between ‘Engine 2 Turbine Overheat’ and ‘Engine Fire’.

During these events, although the flight was controllable and airborne, ECAM had been exploding with a number of messages. Confusion was created in the cabin as priority in dealing with ECAM messages. This had led to fire bottles being discharged and the engine being shut down. However, the ECAM had failed to confirm the disposal of Fire Bottles. As a chain of events, the shutdown of Engine 2 led to Engine 1 and Engine 4 to run on ‘degraded mode’. This could also be considered as the aftermath of the explosion. At this stage, Engine 3 was operating at good conditions.

After this, the crew had encountered problems with hydraulic systems. Unlike the other airplanes, A380 is not entirely controlled with hydraulics. It has electric-hydraulic actuators. It has two different hydraulics:- Yellow &Green; that splits the functions between Brakes & undercarriage retractions and extensions. With Green hydraulics out, nose and body gear was deployed using gravity extension systems.

However, one of the landing gear computer was down, hence no indication was shown as a confirmation of its position as alternate system was used. With most engines in degraded mode, the thrust control was done manually. Various vent, air control and condition systems were down. During this Engine 1 & 4 was set in a particular power mode while Engine 3 was used to control speed.

Sequentially, hydraulic pumps feeding engine 4 failed making Engine 3 as the only engine running in full operating mode producing hydraulics for the whole aircraft. The loss of hydraulics had a great impact on the breaking systems. The wind braking systems was escalated to emergency system which meant that the brake could be applied for just 3 or 4 applications before the accumulators ran out of brake energy.

During these events, the pilots dealt with the ECAM messages handling one at a time as they came through. After the complete shutdown of the Engine 2, the hydraulic systems were dealt. After this ordeal, loss of various flight controls was detected. This was due to the degradation and failure of Electrical Bus 1 and Bus 2. However, plan of action was done through ECAM. It was then decided to operate the APU, but it did not take up any load.

The next issue than required immediate attention was the fuel. It was assumed and confirmed by the second officer on the possible leak of fuel/hydraulic fluid as messages on the balance of the aircraft started to show up. However, the option to transfer the fuel was neglected. Nevertheless, this led to an imbalance of nearly 10 tonnes of fuel. Apart from the fuel and hydraulics, major air leak and pneumatic leak were detected. The leak isolation system however sealed the gaps.

The loss of computer systems deepened the crisis as the crew had no systems in calculating whether the aircraft could be stopped on the runway on the landing. As the aircraft had 50 tonnes of excess fuel which over rides the maximum landing weight, it is critical to estimate if aircraft could be landed in the given landing strip. Hence, it is essential that excess fuel

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4needs to be dumped out before landing. Albeit, the fuel dumping system had failed due to systems failure. Hence, it was impossible to jettison any excess fuel.

A380 is a modern aircraft which is completely computerised which eliminates the paper copies of performance and landing charts. Instead, a performance application which calibrates the performance while inputting the different attributes that would affect landing performance. On the initial run of the application, the test had was unable to calculate many failures and hence failed. At this stage, the crew scrutinised the errors shown by the ECAM.

However, after varying the different attributes and readings, the touch down speed was calculated to be 165kt; which would require 130m of surplus runway. This was available at Singapore Airport. The landing would require the usage of leading edge slats which is combined with the aircraft being overweight. This implies that the aircraft would exceed 35kt faster than the recommended speed suggested by the computer.

At this stage the crew was concerned with the centre of Gravity as they couldn’t transfer the fuel. This meant that the crew required to do weight and balance calculations to determine whether or not they could keep the lateral balance. However, after intense calculations, the aircraft was found to remain within the flight envelope.

With the loss of flight controls, checks were made on the flaps settings and on the basic manoeuvres to ensure the controllability of the craft. Although, the flight should some sluggish behaviour through the test procedure, craft stability was shown by the craft. Hence the aircraft was set to make it’s approach to the Singapore airport runway to make the landing. Approached was commenced 20 miles ahead at 4,000 ft. giving a long stable approach to the airport. Fortunately the weather was adaptable for a safe landing.

The flight was had safely landed with the fuel gushing from the Engine. The brakes that belonged to wing gears had crossed 900C which is critical that could lead to fire with the fuel gushing out from the engine. Fire services were met at the end of the runway. Since the aircraft was on essential power plan, the all communications were barred except for the VHF Radio that is dedicated to the fire brigade. The Engine 1 had failed to shutdown which kept the fire brigades distant from the aircraft.

However, priority was given to passenger evacuation through the flight of stairs. All 433 passengers on board the aircraft were brought to safety.

Results of summary

A sum of 54 warnings were dealt with by the crew flashed be ECAM. The tasks were shared amongst the crew members dealing with the situation aptly. With the advantage of five experienced pilots on board the QF32 came in vital to deal with extensive number messages. This required the monitoring of aircraft parameters precisely. In this case the Crew Resource Management played a vital role in maintaining the scenario without any panic. Monitoring the aircraft parameters were proved to be difficult due to the loss of flight controls and different electrical buses. In case of the wing landing gears, the crew just assumed that the undercarriage had been deployed.

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4Initial investigations reveal that the accident had occurred due to oil leaked into the hottest part of the engine which caused the engine fire. The oil leak had started from the initial hair line crack in the pipe. This however caused the turbine to run out of sync resulting in rotation speed difference. This resulted to the turbine disc to fly apart leading to a shrapnel sliced through the aircrafts wing. This led to an extensive damage to the left wing. The shrapnel had sliced through the aircrafts wing damaging cables which put off some of the flight control systems. It has been revealed by investigation agencies that the flaw in oil tubes in the engine had caused to the entire events. This led to the new safety checks for all A380 aircrafts using Trent 900 engines. This included Qantas, Singapore and Lufthansa Airlines.

Due to the uncontrolled nature of the accident, the damage extended to the engine as the shrapnel tore straight through the wing and went through cutting and destroying other systems such as the electrical, hydraulics and flight control systems. Hence, QF32 suffered multiple system failures due to the turbine failure.

Nevertheless, with the combined effort of the crew and the Engine 3, the flight was able to make it safely to Singapore; despite its complete loss of Engine 2 and partial working of Engine 1 & Engine 4. This meant the loss flight controls, which left the crew to handle the flight with flaps gears to land the aircraft. The landing gear used the emergency gravity system to land deploy the landing gear as the green hydraulics system were damaged and down. The loss of Electrical Bus 1 & 2 led to multiple failures of the electrical systems. APU wouldn’t function as it couldn’t take any load. The multiple ECAM messages prevented the fast calculations that were required by the crew for landing feasibility. Necessary computation was done just after the messages were selected judicially. After which they were able to check the landing possibilities.

The oil leak that caused the disaster [5]

List of recommendations

One of the main recommendations would be making available the hard copies of the landing and calculation charts would enable the easy access to data which could ease calculation. This could be followed by the routine checks that needs to maintained within the turbines. Check for minute cracks within pipes must be brought to attention with immediate priority.

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4Quick shutdown by external access such as by Fire Brigades must be provided for turbines. Further to this, APUs must be enhanced to meet load in all emergency scenarios.

Research must be deployed in understanding the possibilities of employing rapture free tubes to carry hydraulic fluids, as they could be used to control the flight glide at extreme conditions; even during an engine failure.

ETOPS aircraft scenario

In comparison with the conventional aircrafts that depends on two engines, A380 had four engines to support itself for safe landing. However, if the same had happened to ETOPS the capability to deal with the situation would be slim comparatively. . In this case it was able to limp back to Singapore and land safely. Now if it had been an ETOPS which has only two engines there could be a chance that a failure of kind that QF 32 suffered could possibly have taken out both engines and the aircraft would simply have dropped out the sky.

With the failure of one engine, it could lead the second engine to run on ‘degraded mode’ leading to reduced controllability of the flight. This could also lead to extra load on the engine creating an imbalanced thrust control. Apart from this, the amount of fuel burnt would be reduced comparatively leading to imbalance of the aircraft.

A380 was also equipped with sophisticated technology and programmes that could relate with the situation bring up issues that required immediate attention and action. ETOPS given in this situation would find it tougher to recognise the immediate cause and actions required to act.

Albeit, with the availability of Landing Charts and calculation figures available, physical calculation can be done on the ETOPS that would give an quicker and easier results.

QF32 had five experienced pilots that could well handle the situation. Hence the work was distributed amongst themselves. However, in an ETOPS flight, there would be just two cockpit crew available to handle the whole situation. If the two had been bombarded with as many ECAM messages as the QF32, the situation would be chaotic and difficult to deal with.

ETOPS aircraft flying on one engine would run out of fuel as the engine being heavily worked on pulling the whole aircraft along. The excess fuel leak would result to faster fall in the fuel levels, not making the aircraft reach the airport to safety.

Hence, it can be assumed that with the same scenario given to ETOPS aircraft, it would not have been able to survive such accident that was suffered by QF32.

Financial and Industrial Implications

The aftermath of AF32 have created awareness in the airline industry and a much deeper understanding of engines.Rolls-Royce would be badly hit as they are the makers of Trent 900 engines that are used for many of the aircrafts worldwide. With this event, the company would be questioned on its safety and reliability of their engines. Reduced feedback given by the corporate giant to the press would initiate further distrust on their products leaving the

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4airline operators and the aircraft manufacturers on alternate sources such as Pratt & Whitney for engines.

Along with this Rolls-Royce also would have to recall every Trent 900 engines to internal checks. Further investments may have to be made in transporting engines from around the world, rectifying the problems and even to the extent of redesigning the engines.As A380 is a relatively new aircraft, such failures would be highly publicised resulting to a fall in consumer confidence. This would due to the fear of mid-air explosion. Accidents of such explosion could have easily damaged the aircraft which threatens the safety of 400+ passengers. This would be a devastating scenario.

Further to this, financial implications would also include the cancellations of orders and the requirement of alternative engines. Hence this could reduce the sales of Trent 900 engines. From the previous financial year, the pre-tax profit fell to $702 Million from $2.9 Billion which amounts to a net drop of 76% in profits.

Australian agency for transport safety have found the defect in the oil tubes caused the leak within the turbine. This led directly the overheat of the engine leading to the out-sync of disc causing it to explode off the engine.

Hence, Roll-Royce will have to check if the fault is inherent from previous engines. This would require the corporate to extensively investigate and inspect the particular area of the engine which could prevent such leaks. Further to this blast containment also needs further understanding to fully understand the faults. Therefore investments must be made in R&D that could help in investigating the primary causes for crack and the development of structures that would contain the explosion within the engine.

After this incident, all A380 carrying the Trent 900 engines had to be grounded for various inspections. This would require the Rolls-Royce paying for the compensation to the flight owners. This is a very bad scenario for airliners as their scheduled flights had to be replaced with other aircrafts which has to be brought out in. grounding a majority of A380s would require taking up the hangar space which would cost money. This would result to temporary dead money. The company would also have to pay the staff and crews that does the maintenance of the aircraft. The returns from the new aircraft would be stagnated due to the grounding resulting to lower returns on the new investments made by the airline companies.

With respect to the traveller’s concerns, the fear of flying in an A380 would affect the regular airline customers in choosing other airliners that uses alternate aircrafts for the same destination. This would lead to further loses in loosing loyal customers. Further trusts have to be build amongst the customers in using A380s which is energy efficient and a safe flight.

With regards to relationship between Qantas and Rolls-Royce, as their aircrafts are inert on the ground not generating revenues, Qantas is wanting a rapid response from Rolls-Royce to get their checks done with urgency. Eventually, Qantas intends to pursue legal action against the giant engine maker if it has come up with a prompt response on this situation. Hence

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4Rolls-Royce is on the pressure to find a tangible solution to the problem with immediate response.

Timeline summary (refer to timeline and diagram)

After this event, the EASA issued an airworthiness directive to Rolls-Royce regarding the Trent 900 engine. The nature of the event proves that the damage of such consequence is not just limited to the engine, but also on the other components such as the shrapnel which destroyed the turbine. This tore through the wing which affected the electrical and hydraulic systems present on board.

Paper copies of the landing and performance charts were not present it was computerised. This led to low-immediate response to the different situations and landing calculations. However, the ECAM warnings swamped the computer which made it unable to make any of the needed calculations until the errors were cleared. This is a critical issue as this handicapped the crew from having no means of calculations on whether or not safe landing could be performed. From a judicial point, this is a significant note. In terms of CRM, having the extra three members on board have extremely proved beneficial in besieging large number of messages and warnings brought out by the ECAM system. With the extra man power, they were able to handle the pressure of the situation leading to combined effort as a team. The presence of senior pilots who have significant experience in flying came in handy to judge the situation in accordance to the need. Hence the resolution to most problems were dealt efficiently and promptly.

With the use of gravity systems, landing gear systems were used due to the loss of the hydraulic controls.With escalated faults on the control wiring the crew had no indication that; if the landing gear had been deployed.This made them to access the system page for confirmation. This is used during the emergency situations when the hydraulics fail to function. The electrical failures intended that the APU was no longer active and could not supply any electrical power. The far-reaching damage to Engine 2 implies that the fire bottles did not discharge.

After the landing the aircraft, Engine 2 was burning. Additionally, Engine 1 was not being able to shutdown as flight control were jammed. Fuel was gushing out from the Engine 1 which posed danger to both the fire brigade present outside and to the passengers present inside the aircraft. As the brakes were heavily used on landing to reduce the speed, the brake temperatures were dangerously high.

As the runway had been trailed with the fuel, the hot brakes could have led to the explosion of the aircraft on the ground igniting fire on the runway posing threats on the oncoming aircrafts. Hence the passengers were evacuated from one side of the plane as the other side had an uncontrollable and engine on fire. The passengers were evacuated safely using the stairs. This incident has opened and set new standards of safety and check procedures before flight departures.

ATA 100 references

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4 Flight controls: Chapter 27 Air conditioning: Chapter 21 Communications: chapter 23 Fuel: Chapter 28 Hydraulic power: Chapter 29 Electrical power: Chapter 28 Engine turbine: Chapter 72 Engine controls: Chapter 76

References

http://www.youtube.com/watch?v=6LYcpVtaDD0

www.aerosocietychannel.comjournal –Aerospace international –January2011college notesBBC Business report-10 feb-2011

[5] Channel 4 news

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