Challenger 650 BGR

A1Topgun said:
Is it possible using the ATC audio to determine if the Challenger 650 pilot said this?
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I was a ramper for DL for 10 years and deiced/anti-iced many CRJ-200 (50 seaters) in IA. We always did the bare-hand check on the leading top & bottom of the wings on the CRJ-200. The truck had a second hose so the driver would get out and spray the underside of the wings. Or the bucket would drop down to ground level and do it. There have been several other takeoff accidents involving the Challengers involving this subject I don’t know if the ‘650 wing is the same. Our annual training and requalification always included special mention of them and noted the 50 seaters had the same wing (no leading edge devices). The type 4 we used was amazing. We would routinely find it all over aircraft during arrival walk-around. BTW. If a flight crew decides that takeoff is too risky (holdover or just judgement) and goes back to the deice pad, the dricers must first remove the type 4 using type 1. Then they can type 4 it again and restart the HOT clock. We also had a very structured radio conversation with the flight crew when we released them from the pad with all the details and times. They were required to acknowledge they had the deice briefing and usually read it back since all of it was being recorded by the tower.
 
AV8R_87 said:
Prelim is out.
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I watched a video last night by a YouTuber I've not seen before. He discussed the aircraft's timeline of deicing and displayed the FAA chart that establishes holdover times for various temperature and precipitation conditions.

The crew exceeded the holdover time by several minutes. The FDR showed the pitch profile of the aircraft during its brief time in the air was excessively nose up, the right wing quickly stalled, and initiated an unrecoverable roll.

Just prior to the incident, a 121 aircraft that had been deiced and then taxied to the runway, returned to the deice area for another treatment as the crew discussed cancelling the flight and shutting down for the night. While the report didn't specifically state it, I assume that's what happened as the airport was closed after the mishap.
 
Bad weather and get the clients to their destination in France. Bad decision.

The pilots were probably used to flying in the southwest and doing a Europe flight in January? I think there was a deadline they could not fly if the take off was past a certain time.

Factor in the owner's wife on board probably stomping her feet to go.
 
3393RP said:
Just prior to the incident, a 121 aircraft that had been deiced and then taxied to the runway, returned to the deice area for another treatment as the crew discussed cancelling the flight and shutting down for the night. While the report didn't specifically state it, I assume that's what happened as the airport was closed after the mishap.
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The airliners did cancel, but the airport was closed because of the crash.
 
The rotation rate was excessive. They reached 11 degrees nose up and 20 degrees AOA at 11 feet and then used aileron rather than rudder trying to recover. They might have stalled on a sunny day.
 
AOA should be close to the “degrees nose up” value just after rotation, while still level; no?
 
No, AOA would be airspeed, weight and G load dependent.
 
dans2992 said:
Ok, so what’s the difference between AOA and “degrees nose up” assuming level flight?
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What is Angle of Attack?
The angle of attack (AOA) is the angle at which
the chord of an aircraft’s wing meets the relative
wind. The chord is a straight line from the leading
edge to the trailing edge.
 
FlightmechH3 said:
The pilots were probably used to flying in the southwest and doing a Europe flight in January? I think there was a deadline they could not fly if the take off was past a certain time.

Factor in the owner's wife on board probably stomping her feet to go.
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I was thinking the same thing. Owner's law firm is based in Houston.
 
FlightmechH3 said:
Bad weather and get the clients to their destination in France. Bad decision.

The pilots were probably used to flying in the southwest and doing a Europe flight in January? I think there was a deadline they could not fly if the take off was past a certain time.

Factor in the owner's wife on board probably stomping her feet to go.
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Yeah, sounds like this crew didn't have much experience dealing with de-icing. They miscalculated/estimated holdover time and then on top of that both agreed that they would wait another 12+ minutes beyond their incorrect estimated HOT before going back to de-ice. Not sure I follow their logic.

Looks like a bad pairing of contaminated wing and aggressive rotation.

There is no evidence that they heard the airline crews discussing going back to the gate due to exceeding HOT. Wonder if they had overheard those discussions if it would have influenced their decision making?
 
Fearless Tower said:
Yeah, sounds like this crew didn't have much experience dealing with de-icing. They miscalculated/estimated holdover time and then on top of that both agreed that they would wait another 12+ minutes beyond their incorrect estimated HOT before going back to de-ice. Not sure I follow their logic.

Looks like a bad pairing of contaminated wing and aggressive rotation.

There is no evidence that they heard the airline crews discussing going back to the gate due to exceeding HOT. Wonder if they had overheard those discussions if it would have influenced their decision making?
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Hold over tables are for advisory only in Part 91. Unfortunately in the 91 world there is little teaching on deicing. The 142’s (FSI/CAE) don't teach it.

You can see in this accident the PIC or the SIC didn’t understand the HOT. They also totally disregarded the pre takeoff contamination check.

Also I noticed not much type I or type 4 was used.
 
Clayzz said:
What is Angle of Attack?
The angle of attack (AOA) is the angle at which
the chord of an aircraft’s wing meets the relative
wind. The chord is a straight line from the leading
edge to the trailing edge.
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Plus because of the way they are constructed, AOA sensors probably wouldn’t provide accurate AOA under the conditions. They are a flying little wing that’s attached to a synchro or potentiometer. The flying part could have easily been coated with ice and I don’t remember that they are heated.
 
dans2992 said:
Ok, so what’s the difference between AOA and “degrees nose up” assuming level flight?
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Angle of incidence.

Those numbers caught my eye too. 20º AoA at 11º nose up?

However, angle of incidence doesn't account for the full difference here. They give us basically three seconds worth of information:

TimeRadar AltPitchAoADifference
19:44:256'13º19º6º
19:44:2611'11º20º9º
19:44:2714'9º16º7º

Weight on wheels for the mains changed from ground to air at 19:44:24. Interesting that the pitch was decreasing immediately after takeoff, though 10º is pretty normal (Hopefully some Challenger 650 pilots will pipe up with the value here if it's different) so maybe they just over-rotated and were correcting. I'm kind of interested in the next three seconds of data too.

3393RP said:
The crew exceeded the holdover time by several minutes.
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That doesn't give the full picture of how egregious this was: The HOT was only 9 minutes. They nearly doubled that.

I'm curious how much time these guys had, especially the FO, in icing. Low time FO may have just taken what the captain said as instruction and not had the experience or knowledge to know better and insist on going back.

MauiJim said:
Plus because of the way they are constructed, AOA sensors probably wouldn’t provide accurate AOA under the conditions. They are a flying little wing that’s attached to a synchro or potentiometer. The flying part could have easily been coated with ice and I don’t remember that they are heated.
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They're heated. They'd be pretty pointless otherwise.
 
flyingcheesehead said:
Angle of incidence.

Those numbers caught my eye too. 20º AoA at 11º nose up?

However, angle of incidence doesn't account for the full difference here. They give us basically three seconds worth of information:

TimeRadar AltPitchAoADifference
19:44:256'13º19º6º
19:44:2611'11º20º9º
19:44:2714'9º16º7º

Weight on wheels for the mains changed from ground to air at 19:44:24. Interesting that the pitch was decreasing immediately after takeoff, though 10º is pretty normal (Hopefully some Challenger 650 pilots will pipe up with the value here if it's different) so maybe they just over-rotated and were correcting. I'm kind of interested in the next three seconds of data too.


That doesn't give the full picture of how egregious this was: The HOT was only 9 minutes. They nearly doubled that.

I'm curious how much time these guys had, especially the FO, in icing. Low time FO may have just taken what the captain said as instruction and not had the experience or knowledge to know better and insist on going back.


They're heated. They'd be pretty pointless otherwise.
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Initial takeoff pitch setting on the flight director is 12 deg. So these numbers are right in line with that.

I've never paid much attention to the AOA during this phase of flight, though.
 
flyingcheesehead said:
That doesn't give the full picture of how egregious this was: The HOT was only 9 minutes. They nearly doubled that.
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I think it's apparent the pilots had little experience operating in icing conditions, based on their breezy dismissal of adherance to HOT requirements captured on the CVR. It's also significant that the chart gives a range of time for the HOT, and for the conditions present, that was 00:02 to 00:09. It could be argued they exceeded the prudent time limit before the engines were restarted on the deice pad.

I found an accident report for a similar 2002 CL604 crash in England. The aircraft had minimal accretion of ice on the wings, and the aircraft behaved almost exactly as this one did. On liftoff, it rolled immediately and crashed inverted. The AAIB report gives granular detail about the behavior of the wings, which had very little contamination present. It is surprising information, and reinforces the fact that just a bit of frost can take down a jet.

 
RussR said:
Initial takeoff pitch setting on the flight director is 12 deg. So these numbers are right in line with that.

I've never paid much attention to the AOA during this phase of flight, though.
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Yeah, I’d want to compare several AoA data from the same aircraft type during the same phase.
 
I don't fly jets, but I do live where it snows pretty frequently. Ice, to me, is spooky on an airfoil. But if there was blowing snow, so that the accumulation was noticeably higher on one wing than the other, that sounds way worse.

Or in other words, stalling on takeoff would be bad, but having one wing stall while the other wing doesn't would make that bad situation worse.

I don't remember if it was on this accident or another, but in one I thought I heard a report of a pilot on a different aircraft talk about blowing snow, and going back to get de-ice again because of it. Here in the NE, you can have a clear skies sunny day, but if there is accumulation of snow on the side of a highway, and a decent wind, the snow can blow off into the road and cause light snow or ice buildup. I would guess that could be a thing with an aircraft, too, but I don't fly enough in the winter to have ever had it happen.
 
Albany Tom said:
I don't remember if it was on this accident or another, but in one I thought I heard a report of a pilot on a different aircraft talk about blowing snow, and going back to get de-ice again because of it.
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It was this one. My post from upthread:

Flying Keys said:
Later, a Breeze that was getting ready to depart asked the Allegiant over tower freq if they failed the free contamination check. Allegiant said “Yeah, so I don’t know what blew over at the end of the runway but the visibility dropped and it stuck to us like there is nothing there.” I’m guessing there was a drift of blowing snow. Breeze told Allegiant that their [dispatch] was trying to make them go, but “this is stupid.” They discussed deicing again and that they may stay overnight.
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Absolutely concur on the effect of blowing snow, especially if the snow is near (and just below) freezing and the surfaces onto which it’s blowing are the same. It can accumulate quickly.
 
They hammer into you at Challenger school to avoid excessive rotation rates. They also hammer into you to not fly with any kind of contamination on the wings at all. Sounds like both of those things happened. Not the first Challenger to meet its demise in this fashion, and unfortunately probably won't be the last.

I don't miss that airplane, and I don't miss corporate aviation in the least.
 
Groundpounder said:
They hammer into you at Challenger school to avoid excessive rotation rates. They also hammer into you to not fly with any kind of contamination on the wings at all. Sounds like both of those things happened. Not the first Challenger to meet its demise in this fashion, and unfortunately probably won't be the last.

I don't miss that airplane, and I don't miss corporate aviation in the least.
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What’s considered a proper rotation rate? 3 deg/sec or something like that?
 
How are AOA and Pitch measured/calculated in that aircraft? How are they displayed? Anything that would alter the inputs and/or outputs as a result of icing?
 
455 Bravo Uniform said:
How are AOA and Pitch measured/calculated in that aircraft? How are they displayed? Anything that would alter the inputs and/or outputs as a result of icing?
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The Bombardier Challenger 650 utilizes an Angle of Attack (AOA) system primarily to provide stall margin awareness and drive critical safety protections. The system uses pivoting vanes mounted on both sides of the forward fuselage, which align with the local airflow to measure the angle between the relative wind and the aircraft's longitudinal axis.
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System Architecture and Components
The AOA system is integrated with the aircraft's avionics and stall protection systems to ensure safe flight envelopes.
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  • Sensors: Vane-type sensors are located on both sides of the fuselage, specifically below the captain’s pitot probe on the right and below the alternate pitot probe on the left.
  • Heating: For all-weather operation, the vanes are equipped with built-in heaters to prevent icing, which could otherwise lead to inaccurate data or system failure.
  • Data Processing: Real-time data from these sensors is sent to the flight computer. This computer constantly monitors for unsafe conditions and calculates the "Normalized AOA," which is the ratio of the actual angle to the stall angle.
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Pilot Indications
AOA information is presented to the crew through the Rockwell Collins Pro Line 21 Advanced avionics suite.
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  • PFD Display: A normalized AOA indicator is available on the Primary Flight Display (PFD) for advisory purposes. It typically shows a range where 0.1 to 0.8 is a standard reading.
  • Limitations: The PFD normalized AOA indicator is considered advisory only. It does not replace the airspeed indicator as a primary instrument and must not be used during takeoff.
  • Audio Warnings: As the aircraft approaches a stall, the system can trigger loud beeping sounds to alert the pilot.
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Safety and Stall Protection
The AOA system is a core component of the Challenger 650's stall protection architecture.
  • Stick Shaker and Pusher: When the AOA becomes higher than normal, the system activates the stall warning (stick shaker) to alert the pilot. If the angle continues to increase toward a critical stall, a stick pusher may activate to automatically push the nose down and maintain controlled flight.
  • Icing Modes: The system's stall warning schedules can change based on the anti-ice system's status. For instance, when engine anti-ice is turned ON, the indicated AOA reading on the PFD typically increases by 0.05 to 0.1 to account for the reduced stall margin on potentially contaminated wings.
  • Critical Operational Note: The stall protection system assumes a clean wing. Contamination from ice or frost on the Challenger 650’s supercritical wings can significantly reduce the critical stall AOA, potentially leading to a loss of control before the standard stall warning activates.
 
This plane was owned, and pilots employed, by a high-ranking plaintiff law firm in TX. One of the founders of the law firm lost his wife in this crash. This firm also has experience in aviation accident litigation. Wonder what the legal action from this accident is going to look like? The aircraft was owned by a separate LLC (KTKJ CHALLENGER LLC) so do they sue that company? The registered agent for the LLC is one of the law firms founders Jason Itkin.
 
No idea. But I'd bet dinner that he'd rather have his wife back.

And no insult intended, I know there's interest in all of the legal things around accidents. It's just that it takes me a while to get past the people damage part. I am much more of a softie in my old age.
 
GLMS_NC said:
This plane was owned, and pilots employed, by a high-ranking plaintiff law firm in TX. One of the founders of the law firm lost his wife in this crash. This firm also has experience in aviation accident litigation. Wonder what the legal action from this accident is going to look like? The aircraft was owned by a separate LLC (KTKJ CHALLENGER LLC) so do they sue that company? The registered agent for the LLC is one of the law firms founders Jason Itkin.
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Probably blame Bangor airport.
 
Lindberg said:
May you never need one.
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Facts are facts. Residing in a state with no limit on damages, and having conducted business with some of the injury lawyers, I can tell you, whether I ever need or benefit from one of them in the future, they do not care who is responsible. They only care who they can convince a judge or jury is responsible for the most possible financial settlement, and they simply do not concern themselves how that affects any of the defending entities. They just don't. Business is business, and they're in the business of winning judgements and settlements. The larger the better.
 
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