Air France Crash At Yyz

[767jetz]

If it is brake by wire, and power was lost just prior to touchdown, there might not have been time for the back up systems to kick in while the computers were re-booting.

[post="285701"][/post]​

It doesn't work that way. Redundant systems take over in milliseconds. There are no computers to re-boot.

More likely, one contributing cause could be a function of the autothrottle system called "Managed Speed." The airplane is flown in managed speed during an approach, and the computer uses a complicated logarithm based on weight, density altitude, wind, ground speed, etc. to calculate an approach speed. It is a dynamic fucntion that is constantly changing. It looks at something called "Mini-Groundspeed" (minimum ground speed) in order to preserve energy in the event of windshear that shears from a head wind to a tail wind. It is an incredible tool for flying out of a windshear event if one is encountered in the air, like the one that brought down the Delta L1011 20 years ago. I have flown airbus simulators through windshear events with and with out Managed Speed, and I can tell you first hand that it works perfectly as designed.

The draw back is that if you are flying into a strong head wind, due to Mini-Groundspeed the approach speed can be excessively high, making the landing roll longer. In this case it is often better to disengage managed speed on short final and pick a compromise speed. Add to that a long landing, heavy weight, and a wet runway, and it's not hard to see how an over-run is possible.

Just like when the tail fell off of that AA flight in NY, they said something to the effect that the pilot shouldn't have applied so much pressure to the rudder. Does anyone else see a pattern?

[post="285701"][/post]​

I agree that aircraft manufacturers will always try to claim pilot error in order to avoid accountabilility. In the case of AA, the problem was NOT the amount of rudder used. It was the reversal of control inputs from full left to full right, several times. This technique is appropriate in small aircraft and even military and aerobatic airplanes. But no transport catagory airplane is designed to withstand that kind of structural stress. Full rudder input is OK. Full deflection one side to the other is not.
They should have known that.

But in the pilot's defense, there was a lack of information from Airbus on this matter, a lack of specific training from AA, and a design flaw that allowed small pilot inputs to equal large control movements with little feedback to the pilot.

 

[FM2436]

All the talk about fly-by-wire and computer flight controls reminds me of the Airbus accident that occurred during the Paris Airshow about 10-15 years ago. I remember the pictures of the Airbus that did a slow, wheels down, flyby when the pilot attempted to advance power and climb the aircraft. Didn't the computer override the pilots' affects on the control resulting in the Airbus plowing through a heavily wooded area off the end of the runway resulting a firey crash?

 

[sentrido]

pic

Looks like the shutes were deployed

 

[FM2436]

A eerie 24-second video of the 1988 Air France Airbus A320 crash at the Paris Airshow. Listen to the speaker talk about the attempt made to design the pilot out of the aircraft. The speaker then mentions, “This is the first fully automated airplane.â€￾ Scrole down to Airbus A320 crash and click on. It took my accent computer about 10-mintes to download the video.

http://www.linienmc.dk/galleri/video/planes.htm

 

[LUV2FLYHIGH]

I'm just glad everyone is okay and KUDOS to the crew!! The did a great job!!

 

[NWA/AMT]

All the talk about fly-by-wire and computer flight controls reminds me of the Airbus accident that occurred during the Paris Airshow about 10-15 years ago. I remember the pictures of the Airbus that did a slow, wheels down, flyby when the pilot attempted to advance power and climb the aircraft. Didn't the computer override the pilots' affects on the control resulting in the Airbus plowing through a heavily wooded area off the end of the runway resulting a firey crash?

[post="285751"][/post]​

Actually, the incident you refer to took place at Mulhouse-Habsheim in June 1988 and involved an Air France A320 doing a 'fly-by' at a local airshow. The French aviation agency found that the flight crew had overridden the flight control system to perform a high angle of attack manuver at an altitude and airspeed below the capabilities of the aircraft, leaving the crew with insufficient time to execute a safe recovery.

Had the crew not deactivated the Alpha Floor function at 100' AGL to prevent the aircraft from automatically applying power when angle of attack increased beyond limits, the fly by wire flight control system would have prevented this accident.

An excellent analysis of the accident is contained in the book Air Disaster Volume 3 by Macarthur Job.

 

[767jetz]

Had the crew not deactivated the Alpha Floor function at 100' AGL to prevent the aircraft from automatically applying power when angle of attack increased beyond limits, the fly by wire flight control system would have prevented this accident.

[post="285867"][/post]​

You are absolutely correct, and beat me to the punch. Alpha Floor is an auto throttle function that advances the power to max at the critical angle of attack, regardless of throttle position. It is virtually impossible to stall an Airbus. Unfortunately it was disengaged. (I think because of the low altitude. Alpha Floor inhibits at low altitudes when it goes into landing mode, but not sure on that.) Anyway, in that case, by the time the pilot realized it and pushed the power up manually, it was too late.

It wouldn't apply to this case.

This whole discussion illustrates the fact that there are many complex issues and systems to understand in the piloting business, (and accident investigating business) that are transparent to the traveling public. One should always be cautious of playing "Monday morning quarterback." Especially the media.

 

[RDU Jetblast]

No need to be cautious... this is how we learn. And, Thanks to you, I have learned a lot.

 

[PropPiedmont]

Sounds like they landed long. Heavy plane, wet runway, a little bit of float, maybe a wind shift and the next thing you see is a plane in the grass.

Could it be that simple?

I think its happened before.

Did you see the pics with the reversers still deployed?

 

[RDU Jetblast]

http://www.nydailynews.com/front/breaking_...5p-286000c.html

 

[local 12 proud]

Lets not forget that possible fatigue could have been a contributing factor in the critical moment of decision making, but before I get jumped on for being a "Monday Morning Quarterback" several years back an MD80 tried to land in a Severe Thunderstorm in Little Rock, Arkansas in which the Aircraft slid off the runway and struck a Tower. Unfortunately several people perished, including the Captain. I believe fatigue was cited as a contributing factor in this Incident!

 

[767jetz]

Lets not forget that possible fatigue could have been a contributing factor in the critical moment of decision making,

[post="286117"][/post]​

How right you are! Fatigue is almost always a contributing factor to some extent in these circumstances. Which is why I get so irked when management pushes employees in safety related positions to go the extra mile for the "the good of the company." Sure it's great when you save a few bucks by not diverting, or calling in fatigued, etc. But all that savings does not erase even one fatality.

Although some are saying windshear is only a factor in the air, not on the ground, I still maintain that a shear in the flare can certainly contribute to a long landing. And strong head winds associated with a T storm increases the approach speed of an Airbus flown in "managed speed" mode, which can also delay touchdown and hence deceleration. Add to this mix some fatigue, a wet runway, and a runway that does not meet ICAO's recommended standards for "runway safety area," and it's easy to see the potential for exactly this kind of scenario.

As it turns out, this is not the first accident involving an aircraft on this runway crashing into the same ravine.

Here is an excerpt from an ALPA international news letter:

"The crash of Air France Flight 358 in Toronto occurred at an international airport that, unfortunately, does not meet international standards. It is the latest in a series of airline accidents that highlight the dangers of inadequate runway safety areas.

The International Civil Aviation Organization (ICAO) recommends that runways should have a defined “runway safety areaâ€￾ free of obstacles and extending well past the end of the actual runway. In the event that an aircraft is unable to stop normally before the end of the runway, a margin of safety must be maintained so that a slight overrun due to mechanical, weather, or other operational problems does not become a catastrophe.

Air France Flight 358 is not the first aircraft to fall victim to inadequate runway safety areas, or even the first to be “stoppedâ€￾ by the ravine off the end of Toronto’s runways. In 1978, an Air Canada DC-9, following a rejected takeoff, overran what is now Runway 24R, hit the same ravine as did Air France Flight 358, and broke into pieces. Two passengers died. The report from the Canadian government concluded that the ravine “contributed to a high casualty rateâ€￾. "

 

[FrugalFlyerv2.0]

From the Toronto Star: pilor error story

"Pilot error blamed in Pearson crash
12 second delay 'excessive,' Le Figaro quotes experts as saying

French daily Le Figaro said analysis of one of the plane’s flight recorders showed that 12 seconds elapsed between the moment the plane touched down and when pilots applied the reverse thrusters, which are used to assist braking."

 

[FrugalFlyerv2.0]

Another Toronto Star Article: Pearson disaster avoidable

Lengthy article, but here's some samples:

"A Star investigation shows that — despite the plane landing so late there was little chance of it stopping in those conditions — a series of safety improvements at the airport could have saved the plane. Experts say the runway should be longer and should have special grooves to mitigate wet conditions, and the end of the runway should be surrounded with an apron of special concrete designed to stop runaway planes."

"ICAO recommends a 300-metre safety zone at the end of all runways handling international traffic, but will settle for a 150-metre safety zone as an international standard. Transport Canada's standard calls for a 60-metre over-run, with a recommendation for an additional 90 metres.
Pearson's runway 24L meets the 60-metre Transport Canada standard, but not all of the additional 90-metre recommendation (the GTAA would not divulge how much extra safety overrun space it has). It couldn't reach the 90-metre mark without filling in the creek, a move deemed by some to be too costly, and by others to be environmentally insensitive."

"Some experts have also questioned why the pilot chose to land. Other planes had, but conditions were worsening. Mary Schiavo, the aviation expert retained by a group suing the airline, speculates the plane was virtually out of fuel and had no option but to put down. The decision to land ultimately rests with the pilot, who relies on information fed to the cockpit from the tower, from planes that landed earlier, and onboard weather monitoring systems. But minutes before Flight 358 came in to land, a lightning strike disabled runway 24L's anemometer, a gauge for recording the speed and direction of wind — vital information for a pilot landing in a storm. Another tool for transmitting weather information — something Pearson doesn't have — is Doppler radar, which can predict severe wind shears."

"With investigations under way, neither Air France nor Airbus will comment on any aspect of the accident. In a statement by Airbus soon after the crash, the aircraft manufacturer said information gleaned from the preliminary investigation showed all of the aircraft's systems worked, but the runway was simply too wet. The statement, based on partial data, did not mention any software problems."

"There were problems getting out. Several emergency chutes didn't deploy, leaving passengers to jump three metres to the ground as the fire grew behind them, stoking fears of an explosion. Passengers fell on top of other passengers. Almost all of the injuries from the crash were caused by the leap to the ground — broken legs, twisted ankles, sore necks and the odd ruptured vertebrae"