A TAP Air Portugal Airbus A330-200, registration CS-TOO performing flight TP-85 from Lisbon (Portugal) to Sao Paulo Guarulhos,SP (Brazil) with 232 passengers and 11 crew, was climbing out of Lisbon's runway 03 when the crew declared Mayday and stopped the climb at 3000 feet reporting an engine (CF6) failure. The aircraft subsequently climbed to 5000 feet and entered a hold. The aircraft dumped fuel and returned to Lisbon for a safe landing on runway 03 about one hour after departure.
Lisbon police reported debris off the aircraft damaged a number of vehicles in Camarate just north of the runway end.
The airline confirmed an engine malfunction, however said it was not an engine explosion.
A replacement Airbus A330-200 registration CS-TOH departed Lisbon with a delay of about 12.5 hours and is estimated to reach Sao Paulo with a delay of 12:20 hours.
The airline's chairman reported on Jul 16th that a high pressure turbine's vane, located just at the exit of the combustion chamber and thus taking the highest temperatures, came loose, a problem that was introduced during manufacturing of the engine.
On Jun 15th 2016 Portugal's GPIAA released their final report concluding the probable cause of the incident was:
Low temperature hot corrosion (Hot Corrosion Type II) assisted cracking below the fixing platform of High Pressure Turbine stage one blades causing blade separation during the initial climb phase.
Contributing factors were:
- The difficulty for the engine manufacturer, for reasons related to the contracts with the various operators and/or availability, to schedule an earlier Quick Turn that resulted in ESN 811471 engine reaching a CSN above the desired (taking into account the record of previous events) for its removal;
- The engines’ exposure to corrosive elements such as dust, sand, pollution and salt (operation over and close to maritime environment) due to the intrinsic type of operation;
- The engines’ exposure to hot and dry environment due to the intrinsic type of operation;
- The high content of sulfur in aviation fuel at international level.
The GPIAA reported that the first officer (30, ATPL, 4,734 hours total, 112 hours on type) was pilot flying, immediately upon the engine failure the captain (61, ATPL, 8,202 hours total, 3,237 hours on type) took control of the aircraft.
The crew commenced a flex takeoff departure from Lisbon's runway 03 assuming an outside temperature of +39 degrees C and was climbing through 1300 feet AGL, the gear had just retracted, when a loud noise was heard in the cockpit and engine instruments showed an EGT of 1060 degrees C and N1 vibrations of 7.7 units for the right hand engine. The captain, taking control of the aircraft, immediately reduced the right hand thrust to idle and declared emergency advising he wanted to climb straight out to 3000 feet. The crew subsequently worked the related checklists identifying the engine parameters were consistent with damage, in order to secure the engine the crew discharged one fire bottle.
ATC requested the aircraft to climb to 5000 feet for a fuel dump, which the crew complied with. The aircraft dumped about 40 tons of fuel in 41 minutes. The aircraft subsequently positioned for an ILS approach to runway 03, descending through 1000 feet AGL the crew received indication of a nose wheel steering fault and advised ATC they might not be able to vacate the runway. The aircraft landed safely, the crew managed to vacate the runway and stopped on taxiway U4, the aircraft was subsequently towed to the apron.
The GPIAA wrote: "As a result of the contained engine failure, there was some damage to some windows of cars and of a house as the A330 was overflying the town of Camarate (Santiago neighbourhood)."
The GPIAA analysed:
Around the world, from June 2006 until July 2014, there were 13 GE’s CF6-80E1A engines High Pressure Turbine blade liberation events on A330-200/300 aircraft series.
In 9 events, which include the TAP085 one, the engines were equipped with blades P11 and in the remaining 4 were P17 blades.
Out of these 13 events, 11 occurred under the fixing platform at the High Pressure Turbine due to a Hot Corrosion Type II attack.
Most of these events took place whilst the aircraft were in flight (7 IFSD).
Present available techniques unable assessment of under the platform HPT stage one blade condition regarding hot corrosion attacks unless the blades are individually dismantled from the turbine and analysed.
Assessment of under the fixing platform blade condition is performed when the HPT stage one blades are removed at Shop Visit and/or by visual inspection of the blades before Shop Visit (as per SEB 72-0468 - implemented in May 2012), therefore engine manufacturers have a difficult task in scheduling recommended Shop Visits for the turbine stage one blades removal.
One of the most important parameters used to assess engine potential is the number of cycles performed. Consequently, the flight hours to flight cycle ratio is also of vital importance in the “attempt” to determine engine wear.
TAP and GE have been working together on understanding and reducing TAP’s fleet exposure to HPT stage one blade liberation events.
The assessment of the blades is continuous, as the engines go to Shop Visit, with the purpose of gaining further understanding of the hardware condition and, if deemed necessary, re-evaluate the threshold.
The flight hour to flight cycle ratio at TAP is 8.2, considered by GE to be above the area of concern when comparing TAP to the CF6-80E1 fleet as most of these events occurred on engines flying between 3 to 5 flight hours to cycle ratio.
Stage one HPT blade separation event of TAP085 was due to corrosion assisted cracking below the fixing platform, which is similar to other events occurred with CF6-80E1 engines.
At the time of the event, ESN 811471 had 4070 CSN (and 33340 hours TSN).
First stage High Pressure Turbine Blade Damage (Photo: GPIAA):
Fracture surface (Photo: GPIAA):
Incident: TAP A332 at Lisbon on Jul 12th 2014, engine shut down in flight
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