Is Pilot Error to Blame for Icing Condition Accidents?

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Discussion Overview

The discussion revolves around the causes of a plane crash attributed to icing conditions, specifically examining the role of pilot error versus mechanical issues. Participants explore various aspects of aviation safety, pilot decision-making, and the technical capabilities of aircraft in icing situations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants assert that pilots should avoid known icing conditions, suggesting that pilot error is a significant factor in the crash.
  • Others question how a pilot could be unaware of ice accumulation, particularly on the windshield, and discuss the potential for rapid ice buildup.
  • A participant mentions that the flight data recorder indicated the de-icing equipment was activated, but its functionality remains uncertain.
  • Some argue that the aircraft's lack of an automatic de-icing system is a critical issue, referencing past incidents and ongoing legislative efforts to address this problem.
  • There are discussions about the specific aircraft involved, including its design features like pneumatic boots for ice removal and the operational history of similar aircraft.
  • Participants express concern over the conditions leading to the crash, including the possibility that the crew was unaware of the icing conditions until it was too late.
  • Some contributions reflect on the emotional impact of the crash, particularly regarding the passengers involved, including a notable victim related to the 9/11 attacks.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether pilot error is to blame, with multiple competing views on the causes of the accident and the adequacy of the aircraft's safety features. The discussion remains unresolved regarding the specific factors that contributed to the crash.

Contextual Notes

There are references to the complexity of icing conditions and the potential for rapid changes in weather that may not have been anticipated by the flight crew. Additionally, the discussion highlights the historical context of aviation safety regulations and the technical capabilities of the aircraft involved.

  • #31
Engineering news on Phys.org
  • #32
Ivan Seeking said:
When I hear something like that, a caution flag always goes up as old technology is often still the best option. But "expanding bladders" does sound pretty hokey.

The passengers don't count!
 
  • #33
CNN was just discussing the weather conditions that night. It seems that they had cold air with blasts of moisture coming from the South.
 
  • #34
There is a guy who ownes one of these at the airport I fly out of [actual pic]:

http://www.airliners.net/photo/Unti...hoto_id_DESC_&prev_id=1237550&next_id=1237448


(He also owns this one in the picture [it's an actual picture of it]...mmmmmm S76 sexy drool droool drool)
http://www.airliners.net/photo/Unti...hoto_id_DESC_&prev_id=1286667&next_id=1281251

But because the runway is not very long, they have to go to the very end and take off with less than fully fueled to get off the ground. They nearly use the entire runway and can't take off in rain or they won't make it. If that plane ever looses an engine on takeoff its going straight into the trees at the end of the runway at 120+ knots and exploding.
 
  • #35
The commuter plane that crashed near Buffalo was on autopilot when it went down in icy weather, indicating that the pilot may have violated federal safety recommendations and the airline's own policy for flying in such conditions, a federal official said Sunday.

http://www.google.com/hostednews/ap/article/ALeqM5hpSZzqkNMwZvX2xrejSSUOyBGCYgD96C75700

You may be able in a manual mode to sense something sooner than the autopilot can sense it," said Steve Chealander of the National Transportation Safety Board, which also recommends that pilots disengage the autopilot in icy conditions.

Automatic safety devices returned the aircraft to manual control just before it fell from the sky, Chealander said.


http://abcnews.go.com/US/wireStory?id=6882782

I had a gut feeling about that.
 
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  • #36
Cyrus said:
The thing with ice build up is that you should definitely see a noticable change in the handling qualities of the aircraft. It will get more and more sluggish/unresponsive. If this starts to happen, you know you have an icing problem.
The BBC is reporting that the plane was on autopilot, so just like the ATR72 a few years ago. The autopilot is struggling with the ice and when the plane gets unflyable it just drops out, hands the plane back to the pilot and says - your problem!

From other blogs it appears that switching to manual in icing is a good idea but not required.
 
  • #37
It seems that the deicing system was on the entire time.

The National Transportation Safety Board investigator Steve Chealander says deicing was turned on 11 minutes into the flight after it left Newark headed to Buffalo.
http://www.publicbroadcasting.net/wbfo/news.newsmain?action=article&ARTICLE_ID=1470165&sectionID=1
 
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  • #38
Just because a system is on -and working, does not mean it will work. If the rate of ice build up is too large for the de-ice system to cope with, ice is still going to build up on the aircraft.

Major pilot error, IMO.
 
  • #39
Cyrus said:
Just because a system is on -and working, does not mean it will work. If the rate of ice build up is too large for the de-ice system to cope with, ice is still going to build up on the aircraft.

What is a pilot supposed to do if the rate of ice accumulation exceeds the rate of deicing?
 
  • #40
Ivan Seeking said:
What is a pilot supposed to do if the rate of ice accumulation exceeds the rate of deicing?

Don't fly into ice. Ice is very bad. Ice kills. The Maryland State Trooper rescue helicopter isn't ice equiped, so they can't fly in icy weather.

If you experience ice you change your altitude to see if it stops. If it doesn't stop you turn around and leave.
 
  • #41
Cyrus said:
Don't fly into ice. Ice is very bad. Ice kills. The Maryland State Trooper rescue helicopter isn't ice equiped, so they can't fly in icy weather.

Assuming that they were under the direction of air controllers, it sounds like there was nothing they could do. How were they going to know they were flying into severe ice? It almost sounds like the flight controllers were at fault. Or perhaps they couldn't tell that the conditions were as bad as they were?
 
  • #42
Ivan Seeking said:
Assuming that they were under the direction of air controllers, it sounds like there was nothing they could do. How were they going to know they were flying into severe ice? It almost sounds like the flight controllers were at fault. Or perhaps they couldn't tell that the conditions were as bad as they were?

No, you tell the controller you cannot comply with their instructions and have to divert. They would know because they shouldn't have left the autopilot on. Like I said, the controls would get very sluggish, and engine power would start creeping down. You can feel the ice on the airplane. The same way you can feel the pile of ice on your car if you don't clean it before you drive off. The pilot in command (PIC) is responsible for the safety of the aircraft, not the controller.
 
  • #43
Cyrus said:
No, you tell the controller you cannot comply with their instructions and have to divert. They would know because they shouldn't have left the autopilot on. Like I said, the controls would get very sluggish, and engine power would start creeping down. You can feel the ice on the airplane. The same way you can feel the pile of ice on your car if you don't clean it before you drive off. The pilot in command (PIC) is responsible for the safety of the aircraft, not the controller.

How long does it take for ice to accumulate to dangerous levels in the worst conditions?
 
  • #44
Ivan Seeking said:
How long does it take for ice to accumulate to dangerous levels in the worst conditions?

I've never flown in ice (nor do I want to try it), but from what I recall reading, it can take a few minutes. Then again, I'm not flying in bad weather all the time like the pros, so I'm sure they are trained to deal with worse weather.

According to my Jeppsen book:

In extreme cases, it can take as little as 5 minutes for 2 to 3 inches of ice to accumulate on the leading edge of the airfoil... Some aircraft may experience as much as 50 percent decrease in lift after the build up of only 1/2" of ice.

The problem with ice is that it changes the shape of the airfoil at the leading edge. Most of the lift is created at the first 1/3 of the airfoil section, so its very important that this section is clean and as designed.
 
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  • #45
So while in auto-pilot, it would be fairly easy to get a significant accumulation in a minute or two, without knowing it.

I did hear that at the last moment, they tried to change to a new vector.
 
  • #46
Pilot's actions scrutinized in Flight 3407 crash
http://news.yahoo.com/s/ap/20090216/ap_on_re_us/plane_into_home
Chealander said information from the plane's flight data recorder indicated that the aircraft pitched up at an angle of 31 degrees in its final seconds, then pitched down at 45 degrees.

The plane rolled to the left at 46 degrees, then snapped back to the right at 105 degrees — 15 degrees beyond vertical.

Radar data shows Flight 3407 fell from 1,800 feet above sea level to 1,000 feet in five seconds, he said. Passengers and crew would have experienced G-forces up to twice as strong as on the ground.

The plane crashed belly-first on top of a house about six miles short of Buffalo Niagara International Airport, two to three minutes from when it should have touched down on the runway.

Just before they went down in a suburban neighborhood, the pilots discussed "significant" ice buildup on their wings and windshield. Other aircraft in the area told air traffic controllers they also experienced icing around the same time.

Chealander said in an interview that the pilot may have rejected federal safety recommendations and the airline's own policy for flying in icy conditions by leaving the autopilot on even after he notified air traffic control that the flight crew had spotted ice on the leading edge of the wings and the windshield.

The Dash 8 Q400 plane, operated by Colgan Air, was equipped with a "stick shaker" and "stick pusher" mechanism that rattles the yoke to warn the pilot if the plane is about to lose aerodynamic lift, a condition called a stall. If not corrected in time, the mechanism automatically pushes the stick forward to avert a stall.

Chealander said the plane was on autopilot until the "stick shaker" and "stick pusher" kicked in, automatically putting the plane back in the pilot's hands.

At some point, the pilot switched on an anti-stall device that increases the speed of the plane by 20 knots and gives a pilot more margin to recover from a stall if it occurs.

Asked whether the pilot might have overreacted by pulling the stick back when it automatically went forward, Chealander said, "Yes, it's possible."

Still, he was careful not to be critical of the pilot.

"Everything that should have been done was done, so we keep looking," he said. "We keep looking, trying to find out why this happened."

Chealander said the plane's deicing system was turned on 11 minutes after it took off from Newark, N.J., and stayed on for the entire flight. Indicator lights showed the system appeared to be working.

He said the pilot was being "very conservative" by turning it on so soon.
. . . .
One key question would seem to be why the plane pitched so violently? The condition of the plane seem to change abruptly.

Also, did he leave auto-pilot on too long? He did activate the anti-stall system.
 
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  • #47
It's not looking good for the pic for this crash. It's looking more and more like he may have overcorrected when he realized what may be happening. While no "illegal" to have the autopilot on in icing conditions, I liken it to having your cruise control on in rush hour. Not a bright move.
 
  • #48
The latest I heard is a concern that the pilot let the air speed decrease too much, and at the point when he should have put the nose down to get air speed, he increased power but pulled back on the stick, and the plane apparently went into an unrecoverable stall - and subsequently pancaked into the house.

Could the icing have affected the air speed indicator?

I wonder why the air speed would have been too low?
 
  • #49
Astronuc said:
I wonder why the air speed would have been too low?
Too slow for conditions probably. If the wings were deformed from icing, the pilot would probably have to increase speed to generate enough lift to stay in the air. I wouldn't want to be the one at the controls trying to guess what the plane's stall speed is with iced wings.
 
  • #50
Astronuc said:
Could the icing have affected the air speed indicator?
Icing is a problem so the pitot tubes have electric heaters
 
  • #51
I heard a pilot saying that too much flap in this situation could lead to a tailstall. I thought extended flaps anytime you need more lift.
 
  • #52
The plane was on auto pilot until just before the crash. Auto pilot has a feature commonly called "stick shaker stick pusher"

As a plane approaches stall speed the Yoke will vibrate then within seconds if no action is take by the pilot the yoke will push forward to increase speed.

There is now some speculation that the pilot may have been alarmed by the forward motion of the yoke and pulled back too far resultiing in the initial unexplained 30 degress + upward nose pitch.
 
  • #53
It seems to me that everyone is overlooking something. You're all concentrating on icing affecting the wings and lift. Let's not forget that it takes even less ice to screw up the horizontal stabilizer, which controls attitude. It's possible that the pilot had no pitch control and didn't realize it until George kicked out and handed it back to him.
If the ice had also jammed the elevators, he might have horsed back on the yoke and broken it loose, which might have resulted in a higher nose position than intended.
 
  • #54
Astronuc said:
I wonder why the air speed would have been too low?
Did the airspeed decrease before or after he pulled back on the stick? With the aerodynamics destroyed, there is a lot of room to speculate on what the plane would do, but the ice could have contributed to the violence of the pullup and if the pullup caused an immediate stall (a stall is caused by a too-high angle of attack, not a low speed), the airspeed would drop rapidly and the plane would go from flying to falling like a brick in just a few seconds. I'm interested to see how much detail we get about what the plane was doing those few seconds - it may be quite revealing.

And once the airspeed gets pretty low, there is no possibility for control left. The violent rolling and pitching might not be what you would envision a flying airplane to do - it could be more like a leaf or a piece of paper fluttering to the ground.
 
  • #55
With the aerodynamics destroyed, there is a lot of room to speculate on what the plane would do,
The stick-shake stall warnign is presumably based on the design stall speed of the plane, not the stall speed of the new ice+aerofoil wing.
Is there any way for the system sense how close you are to stall from the real time response of the plane to controls?
 
  • #56
mgb_phys said:
The stick-shake stall warnign is presumably based on the design stall speed of the plane, not the stall speed of the new ice+aerofoil wing.
Is there any way for the system sense how close you are to stall from the real time response of the plane to controls?

I don't think so that is why they recommend that the pilot be in control during icing conditions. The auto pilot compensates for conditions a pilot would have already felt in the controls.

There is also an issue with the landing gear being lowered was it the pilot or the autopilot?

Apparently it was the pilot who raised the gear again a few seconds later.
 
  • #57
WOW!

45 degree turn WHILE a 45 degree nose down IS INSANE!

When we practice 45 degree turns we call it 'steep turns' and it is STEEEP. YOU FEEL THE G's in that kind of a turn. They were CRANKING that airplane LIKE HELL. They could have very easily just ripped the god damn wings off!

Danger: Thats a GREAT analysis I didn't think of! I emailed it to my professor at NASA langely. I'll post his reply when he sends it. He does crash analysis as well on the side. I'll also ask my helicopter professor who also does crash stuff.
 
  • #58
What is the difference between a "wing stall" and a "tail stall" and how should you correct each...I heard an aviation expert discussing it on the radio and I didn't catch all of the details...I thought he said the correction of one is the opposite of the other?
 
  • #59
http://aircrafticing.grc.nasa.gov/courses/inflight_icing/related/3_2_3f_RI.html

The gist with a tail stall is related to flap usage because the wings are still producing lift with the decreased speed but the tail can not. It seems like a design flaw to have a portion of the flight envelope that can have the wings still producing lift and the tail section not. The icing in this case could have created that in that the icing screws up the aero of the tail so it stalls sooner than it normally would. The cool things about the video above are:
1) The statement that even though you correct very quickly, the aerodynamics has a lag and takes some time. Hence the statement that if you have this happen on approach, you're toast.
2) The flight video shows a stalled stabilizer in flight.
3) You can see how violent the yoke can become in a real stall.

MGB...to answer your question, NO they are calibrated for a clean wing.

Here's a nice quote that shows, I think, that the pilot had the right idea, but the wrong implementation:
William Rieke, a NASA research pilot and chief of aircraft operations at NASA Glenn, says to consider the 180-degree turn only if you have no other options -- like an airport in front of you. "If you are getting ice and you have to do a 180 to get out of it and in the process go back through [the ice] and accumulate more -- or worst case, if the air mass is moving in the direction you just turned to, you may be in it even longer than your initial encounter." If terrain clearance or clouds were not an issue, Rieke would prefer to descend 3,000 feet or, if the airplane was powerful enough to climb with the weight and drag of accumulated ice, climb 3,000 feet in an effort to get out of the icing conditions. (Most training aircraft would not be able to climb if they were carrying an appreciable quantity of ice.)

They were at a low altitude within 7 miles of the airport. Undoubtedly the guy was lining up for final. He was thinking just get this thing down ASAP. Unfortuantely ASAP in this case was too soon. This will be supported when they release the configuration of the airplane and it's speed just prior to the crash.

http://flighttraining.aopa.org/ft_magazine/fullstory.cfm?id=5222&issue_title=February
 
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  • #60
Radical steep turns are sometimes used to dislodge the ice from wings. Even the B-1 bomber pilots were taught to use the method. They usually crashed. The B-1, built to fly at supersonic speed and at tree top level over Siberia had no deicing system.
 
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