BBC: Brazil jet thrust reverser 'off' ( No wonder he was speeding down the runway)

BBC ^ | Friday, 20 July 2007, 09:31 GMT 10:31 UK | BBC Staff

[Ernest_at_the_Beach]

Brazil jet thrust reverser 'off'

The video footage shows the final moments of the flight Runway footage

A thrust reverser on the plane which crashed in Brazil, killing some 200 people, had been deactivated during maintenance checks, the airline says.

The reversers can be used to help jets slow down on landing but Tam Airlines insisted the deactivation was in accordance with proper procedures.

The Tam Airlines' Airbus 320 overshot the runway at Sao Paulo's Congonhas airport, hit buildings and exploded.

There has been intense speculation but no confirmation on the crash's cause.

But the crash has brought mounting calls for Congonhas airport to close.

Brazilian President Luis Inacio Lula da Silva, who has been criticised by opponents for his low profile since the crash, will address the nation on Friday and is expected to announce new measures on air safety.

'Higher speed'

Tam Airlines said the right thrust reverser was "deactivated" at the time of the accident "in conditions stipulated by the maintenance of the manufacturer Airbus and approved by [Brazil's] National Civil Aviation Agency".

See where and how the crash unfolded

Tam Airlines' comments came after Brazil's Globo TV said a problem with the right thrust reverser had emerged four days before the crash.

Tam said Airbus's own manual says an inspection can be done up to 10 days after it is first detected and that the plane can continue to operate in the meantime.

We have operated thousands of times under heavy rain and nothing has happened Jose Carlos Pereira, Infraero Witnesses describe horror Q&A: Plane crash

Globo TV also reported that the same plane had problems landing at Congonhas the day before the crash.

The channel said the plane only managed to stop at the limit of the runway. The pilot told air traffic controllers it was very slippery but did not mention any other problems, the report said.

The crash occurred in wet conditions on a recently resurfaced runway that has been criticised as being too short.

New video footage shows some of the final moments of the Tam Airlines flight from the southern city of Porto Alegre, and another similar plane that had arrived earlier.

It appears to show the Tam plane travelling along one section of the runway at higher than normal speed.

AIRBUS A320 Launched: 1988 In operation: 1,700 Operators include: British Airways; Air France; Air Canada; China Eastern Airlines; Iberia; United Airlines; Jet Blue Airways

It shows the first aircraft apparently taking 11 seconds to travel along the visible section, while the plane that crashed covers the same distance in three.

The Airbus 320 jet appears to continue speeding along the runway without slowing, before disappearing out of view. The flash of an explosion can be seen a short time later.

According to Globo TV, the Brazilian air force, which oversees the country's air traffic control system, believes the footage shows the plane was travelling at excessive speed.

As the plane careered towards the busy road nearby, one theory is that the pilot tried to take off again. The aircraft crossed the road and ploughed into a Tam Airlines building.

"That he jumped over the avenue was an indication he tried to take off. If he didn't [try to take off] he would have gone nose down at the end of the runway," Brig Jorge Kersul Filho, director of the Air Force's Centre for Investigation and Prevention of Air Accidents, said.

Some 180 bodies have been recovered from the burnt wreckage, says fire chief Nilton Miranda, adding another 20 bodies are expected to be found.

Most of the passengers and crew on board the flight were Brazilian.

[Ernest_at_the_Beach]

Awful!

[Gay State Conservative]

The Airbus manual instructs pilots to disable thrust reversers during a landing? I ain’t no aviation expert but that sounds *crazy*!

[Red Badger]

I bet the pilot was unaware of the reverse thrusters being de-activated, until it was obvious........

[finnman69]

If the thrust reversers were deactivated, would he not have actually been increasing his speed? I thought thrust reversers mean you gun your engines, but deflectors force the thrust into your direction of travel, slowing the aircraft. Instead, he was actually speeding up?

[DuncanWaring]

I would think that deactivating one thrust reverser would lead to serious asymetric thrust problems.

[CarrotAndStick]

From Wiki:

Operation

Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift and high speed limit the effectiveness of the friction brakes located on the landing gear. Reverse thrust is always selected manually, either using levers attached to the thrust levers, or by moving the thrust levers into a reverse thrust ‘gate’. When thrust is reversed, passengers will hear a sudden increase in engine noise, particularly those seated just forward of the engines.

The early deceleration reverse thrust provides can reduce landing roll by a third or more. Regulations dictate, however, that a plane must be able to land on a runway without the use of thrust reversers in order to be certified to land there as part of scheduled airline service.

Once the aircraft’s speed has slowed, thrust reverse is deselected to prevent the reversed airflow from raising debris in front of the engine intakes where it can be ingested, causing foreign object damage. Thrust reverse is effective at any speed, and, in unusual circumstances, can be used all the way to a stop, or even to provide thrust to push the aircraft backward, though aircraft tugs or towbars are more commonly used for that purpose.

If the full power of reverse thrust is not desirable, thrust reverse can be operated with the throttles set at less than full power, even down to idle power, which reduces stress and wear on engine components. Reverse thrust is sometimes selected on idling engines to eliminate residual thrust, particularly in icy or slippery conditions, or where the engines’ blast could do damage.

[conservatism_IS_compassion]

thrust reversers mean you gun your engines, but deflectors force the thrust into your direction of travel, slowing the aircraft. Instead, he was actually speeding up?

by the time he crashed, the pilot must have figured out that his reversers weren't working, and all efforts to use them were counterproductive. But by the time he could figure that out, the crash was baked in the pudding.

[Truth29]

If the pilot was not aware of the deactivation, I think you are right. Even if he was, the absence of the thrust reversers would have made for a much longer landing roll.

[mowowie]

I was thinking that as well. You would think that there would be somekind of indicator to warn the pilot beforehand.
I was just on one of these planes. Scary thoughts thinking of myself and fellow passengers strapped in and burning to a crisp.

[Spktyr]

It’s an Airbus. Chances are good that the computer wouldn’t allow the use of just one thrust reverser for just that reason, even though it might have saved the aircraft (once the wheels are on the ground, asymmetric thrust is much less of an issue).

[Ernest_at_the_Beach]

I assume the AirBus has a black Box so hindsight analysis can see exactly what the Pilot was doing.....

[9422WMR]

If it ain’t Boeing,
I ain’t going!

[Red Badger]

They recovered the BB’s very quickly..........

[Old Professer]

I thought the runway made him do it?

[DuncanWaring]

I would certainly hope the computer wouldn’t allow use of just one thrust reverser ... although in that case, the article should say “thrust reversers were disabled” ... although the article is undoubtedly written by a graduate of a Journalism school ...

[stinkerpot65]

With a corrupt government, who knows what will eventually turn up on those boxes.

[Calvin Locke]

The BBs were sent to the US for analysis.

Maintenance, huh?

I seem to remember reading that a US airline was off shoring maintenance to a Brazil-based company.

[GovernmentShrinker]

My understanding is that the black boxes are being analyzed by the US NTSB, not by the Brazilians.

[Spktyr]

Um, one TR might have been better than none.