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.

[ops33]

I’ve worked around aviation for over 30 years, first as a firefighter, then an airt raffic controller and then to airport operations. Currently I work with the FAA developing instrument approach procedures. When you are flying you are basically inside a fuel tank with wings. Fuel and flammables are just about everywhere, under the fuselage, inside the wings, engines, etc. The only comfort is that in a crash like that the passengers don’t survive very long. About the only chance they have is if the aircraft breaks up and allows some of the passengers to escape. This is what happened when the L-1011 crashed in Souix City, IA. The aircraft broke up into three pieces, some of the passengers were tossed out, and some were able to escape. There were even a few passengers who were thrown clear of the wreckage and escaped completly unharmed.

[Paleo Conservative]

Aren’t aircraft interiors supposed to be nominally flame-retardent?

Yes, but it probably isn't much help when you crash into a gas station.

[pissant]

Scary stuff!!

[Lx]

This is what happened when the L-1011 crashed in Souix City, IA

That was a DC-10. You might be thinking of the Delta flight?? going into DFW that hit wind shear and broke up.

[DuncanWaring]

The picture seems to show the bulk of the fire inside the cabin.

I would have thought the bulk of the fuel was carried in wing tanks. Plus, fuel from the gas station would also have been outside the aircraft.

[ops33]

No, you’re right, it was a DC-10. My mistake.

[DuncanWaring]

Well that just stinks.

[MarkL]

The reversers can be used to help jets slow down on landing

"Can be used?!?!?!" Thrust reversers are the main deceleration tool used on modern jets!

This also explains why the plane was moving so fast... The reversers are engaged, and then the pilot increases thrust. I don't know if they to anywhere near full throttle, but they give it quite a bit! Without the reversers, they would have accelerated upon landing.

Mark

[zipper]

The problem here is that the pilot tried to land a somewhat heavy aircraft on a relativly short WET runway with no reverse thrust.

And not grooved, which significantly reduces the coefficient of friction on runway surface. The only thing they had going for them is the fact that since the surface was new, it was not likely to have rubber buildup from other aircraft previously landing in the opposite direction; a common cause of poor braking in wet conditions in the last 3000 feet of runways.

Aircraft braking on a wet runway can be marginal due to hydroplaning, and with no reverse, you only have brakes to stop the aircraft.

Don't forget the spoilers. Spoilers "spoil" the lift so not only do they produce drag, they immediately help put weight on the wheels for more effective braking. Spoilers are not nearly as effective as brakes, but they amplify the effectiveness of the brakes. Spoilers are more effective than reverse. Anyway the reverse thrust is not factored into the landing distance for dispatch or for in-the-air computed landing distances. And if it were it would have contributed only marginally, since the right one was pinned.

In a normal landing the spoilers are "armed" and don't deploy until the aircraft has touched down, and the autobrakes (if armed) are applied only if the spoilers are armed, after touchdown.

[zipper]

Thrust reversers are the main deceleration tool used on modern jets!

Not correct. See the next-to-last paragraph of my post #51.

[zipper]

Good post, except for:

"...aircraft braking on a wet runway can be marginal due to hydroplaning, and with no reverse, you only have brakes to stop the aircraft."

See post $51

[ItisaReligionofPeace]

I pray it was over in an instant.

[ItisaReligionofPeace]

Do you have any idea what you are talking about? Let me answer that: No!

[Brimack34]

What a picture. To bad it was from such a tragedy.

[RckyRaCoCo]

I remember there being a USAirways pilot here on FR(I know they operate A320's). I would imagine there might be a few other ATP's here also. Perhaps they could offer some insight on this tragedy.

I keep hearing about the "short runway" being a contributing factor. But I think there are shorter runways that operate mid-size airliners. I flew into Detroit City airport in January(snow/ice/wind)back in the 90's on Southwest airlines(737)and I believe that runway to be only about 5100 ft. Also landed many times at Orange County(KSNA)with a runway length of 5700 ft., they land planes as big as 757's and A300's with no problem. According to ref. site Congonhas Int´l Airport has the following runway config.

Runway 1: Heading 17R/35L, 1,939m (6,361ft), Aircraft size max: AirBus Runway 2: Heading 17L/35R, 1,497m (4,911ft), Aircraft size max: B737

Not saying it had no factor, especially in bad weather(braking action), I guess anything is possible.

Heh, on flight simulator i've overrun a few times when I forgot to disengage the auto throttle and that would tell the plane to maintain 140 kts...zoooom off the end, brakes or no brakes. I seriously don't think the "real thing" would allow that. Also tryed going around with spoilers still engaged...not a good idea either.

Always remember when an A320 flew into the trees

fly by wire...ouch

With the black boxes(CVR/FDR)intact lets hope they can determine the cause.

[ab01]

You're correct. However, the function of the spoilers is to reduce the lift component which in turn makes the brakes more efficient/effective. Autobrakes are usually pretty good. The problem is that as soon as the pilot tries to override them, the net result is less brakes as it is physically impossible to exert more pressure than the max brake setting. At least, that what the engineers told me. Bottom line,the pilot tried to land, couldn't slow/stop, tried to abort the landing, and ran out of runway. My opinion is based on Boeing aircraft performance. Airbus may have different procedures/techniques.

[JayNorth]

You might be thinking of the Delta flight?? going into DFW that hit wind shear and broke up.

I knew a hotel employee who worked at a DFW airport hotel during that crash. In a gallows humor moment, a lot of the survivors I guess had very minor little cuts all over their exposed skin and the medical care professionals had placed all these little BandAids on them. In a perverted way the front desk staff couldn't help laughing (hopefully in the back office) at the absurdity of surviving a major plane crash and having a few BandAids to tell the tale.

[epow]

My opinion is based on Boeing aircraft performance. Airbus may have different procedures/techniques.

My son has flown the Airbus 319 and 320 for several years now after transitioning from the Boeing 727. I am going to ask him about the engine thrust reversers being deactivated, and if his airline allows the planes to fly in that condition. In my flying experience I usually see the reversers being used at almost every landing.

The 320s my son flies are set up to seat about 160-170 passengers, while the Brazilian plane appears to have been carrying around 200. That extra weight would probably make engine braking more important on that short wet runway than it normally is.