KAPF - Naples Florida - Challenger crash on highway
As for the median, we would need to know the depth, width and slope to determine whether a wingtip would contact before the gear. One wingtip contacting before the other would trigger high yaw and roll rates. I would be most pleasantly surprised if a similar aircraft remained in the median. The worst case would be being deflected into oncoming traffic.
The median barrier could be high enough to breach the wing tanks and add to forces directing the accident aircraft into oncoming traffic. Perhaps the median could work out for a high wing single.
As for the 700m pond, it was about a mile closer to the point where power was lost. People with access to appropriate sims could see if either large pond could be made from the power loss point. The NTSB might decide to research this on a sim. Often several crews are run through accident scenarios on a sim. The "success" rate would be interesting data.
The median barrier could be high enough to breach the wing tanks and add to forces directing the accident aircraft into oncoming traffic. Perhaps the median could work out for a high wing single.
As for the 700m pond, it was about a mile closer to the point where power was lost. People with access to appropriate sims could see if either large pond could be made from the power loss point. The NTSB might decide to research this on a sim. Often several crews are run through accident scenarios on a sim. The "success" rate would be interesting data.
We can speulate on their options to the ying yang and never really know; only the 2 pilots knew what the situation really was in that cockpit. What is of more interest is the possible cause of the double flameout. Does anyone have info on the fuel state on departure for example?
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ripped,
I would have sent this privately as it does not directly relate to this accident but I wanted to share. I did fly the 601-3A for about 7 years but this is not about that. It's about RAT's and HMG's. Again not related. My younger brother flew for United. About 20 years ago on a EZE-MIA night flight they lost electrical power south of Columbia. B767 ETOPS. They were unable to get RAT (I think that's what the 767 has, if not HMG). System design prevented auto deploy (apparently no manual deploy) because the system sensed normal AC power from both gen's. Problem was the ground. Both the AC and DC system share the same grounding bracket which had a little bit of corrosion breaking the ground. Google Cast BP Witcher and United Airlines. It was flight UAL 854/EZE-MIA/13 April 2004.
I would have sent this privately as it does not directly relate to this accident but I wanted to share. I did fly the 601-3A for about 7 years but this is not about that. It's about RAT's and HMG's. Again not related. My younger brother flew for United. About 20 years ago on a EZE-MIA night flight they lost electrical power south of Columbia. B767 ETOPS. They were unable to get RAT (I think that's what the 767 has, if not HMG). System design prevented auto deploy (apparently no manual deploy) because the system sensed normal AC power from both gen's. Problem was the ground. Both the AC and DC system share the same grounding bracket which had a little bit of corrosion breaking the ground. Google Cast BP Witcher and United Airlines. It was flight UAL 854/EZE-MIA/13 April 2004.
Landing a glider as opposed to a Challenger I would hazard a guess is somewhat very different!
FDR will certainly show if this was the case.
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Short video clip bouncing around the internet demonstrating the plausibility of inadvertent engine shutdown on a CRJ. Video shows the left seat pilot reaching across the rear of the thrust levers for the flap handle while the right seat pilot pulls thrust levers to idle. However, the engine shutdown interlocks (red switches) on the back of the thrust levers are actuated by pressing against the left seat pilot’s right forearm, allowing the unintentional movement of the thrust levers through idle to fuel cutoff.
FDR will certainly show if this was the case.
FDR will certainly show if this was the case.
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Stop with the "they should have landed here or there". If you have ever gone down at low altitude with no power you simply look ahead and pick the best thing in about 3 seconds. Interstate would be high on the list anyway.
As for the why, likely fuel exhaustion or birds. Simply not enough fire spread with a wing ripped off spilling 30 mins reserve fuel all over the place as the airplane spun around. It ignited on impact probably due to massive compression like a diesel engine. Charter ops usually have a decent fuel contract at the home base and try to buy as little as possible while out. This 2 leg trip would have been possible without a stop, but no room for error. They would have known as the EICAS would have told them. As far as frozen fuel no way. It would have been good and warm from the oil heat exchangers. Could have been an issue with fuel quantity sensors. And they had less then they thought, but still both engines failing at same time has me perplexed. Even with exhaustion its unlikely for them to fail at the same time.
Birds? Naples has pelicans, trust me small birds do little to these engines. I have hit a ton with no issues. But its plausible.
Single engine failure and shut down the good engine? Possible.
You cannot restart those engines without apu running. On a charter I would expect them to start it on landing to save hours and fuel. As for the rat, it will deploy when no power to main bus if I remember correctly. I had to deploy one for testing and as soon as you turn off power from both gens, it deploys. Not sure if apu is running, but I think it won't as the main bus is powered.
If you had a dual at low altitude you would not have enough time to start the apu and therefore pick a landing spot.
Fuel contamination is possible.
CF34 engines are bulletproof and can take a lot of abuse. Not like the old Lears that a blue jay would flame you out.
Very experienced pilots, but everyone I know will tell you of a low fuel situation at some point in their career. You always make it until you don't.
There are so many possibilities off the top of my head, but I know what a gallon of diesel looks like on a bonfire. The wall was pretty burnt up not near resting place so a lot of it may have exited there and burned up and nobody got it on film. I can only expect whatever it was they did a good job saving 3 lives. Any of these problems where they were would have ended in disaster regardless of pilots and maybe much worse.
As for the why, likely fuel exhaustion or birds. Simply not enough fire spread with a wing ripped off spilling 30 mins reserve fuel all over the place as the airplane spun around. It ignited on impact probably due to massive compression like a diesel engine. Charter ops usually have a decent fuel contract at the home base and try to buy as little as possible while out. This 2 leg trip would have been possible without a stop, but no room for error. They would have known as the EICAS would have told them. As far as frozen fuel no way. It would have been good and warm from the oil heat exchangers. Could have been an issue with fuel quantity sensors. And they had less then they thought, but still both engines failing at same time has me perplexed. Even with exhaustion its unlikely for them to fail at the same time.
Birds? Naples has pelicans, trust me small birds do little to these engines. I have hit a ton with no issues. But its plausible.
Single engine failure and shut down the good engine? Possible.
You cannot restart those engines without apu running. On a charter I would expect them to start it on landing to save hours and fuel. As for the rat, it will deploy when no power to main bus if I remember correctly. I had to deploy one for testing and as soon as you turn off power from both gens, it deploys. Not sure if apu is running, but I think it won't as the main bus is powered.
If you had a dual at low altitude you would not have enough time to start the apu and therefore pick a landing spot.
Fuel contamination is possible.
CF34 engines are bulletproof and can take a lot of abuse. Not like the old Lears that a blue jay would flame you out.
Very experienced pilots, but everyone I know will tell you of a low fuel situation at some point in their career. You always make it until you don't.
There are so many possibilities off the top of my head, but I know what a gallon of diesel looks like on a bonfire. The wall was pretty burnt up not near resting place so a lot of it may have exited there and burned up and nobody got it on film. I can only expect whatever it was they did a good job saving 3 lives. Any of these problems where they were would have ended in disaster regardless of pilots and maybe much worse.
Quote.... I started wondering if the grass median in the middle of the lanes would not have been the better option.. thoughts?
Well No.... Landing straight down the middle of the carriageway, in between vehicles, would have been just Ok.
Well No.... Landing straight down the middle of the carriageway, in between vehicles, would have been just Ok.
In the correct lane of course. Don’t want any head-on do we?
Unlikely that it was a known low fuel situation kept from ATC. They would have chosen a higher pattern it they new that flame out was imminent. But you never know like on LMI2933.
I do not believe that a 25kh pilot or FO would maneuver himself into a Challenger glider ops corner.
I do not believe that a 25kh pilot or FO would maneuver himself into a Challenger glider ops corner.
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I am interested in knowing what the FDR and CVR shows, as we all are.
My feeling and what the evidence in a very limited way shows is first both engines quit, presumably simultaneously. I can only attribute lack of fuel to that as a “reasonable” contributing factor.
Both engines are fed by the single tank that has no quantity indicator. Instead it has low level warning annunciator. Probably red. From that indication to no fuel remaining in the collector tank would be in part determined by the combined fuel flow and possibly by either no fuel transferring or insufficient fuel flow from the main wing tanks. Either because they were empty or some other reason the fuel was not able to flow into the collector.
I would best say the annunciation of that Low Level does not leave the crew with much to go on unless they anticipated it because they initiated a flight with not enough fuel for the flight. If they were tankering extra then they had enough fuel and we go back to the low level in the collector tank. This should be as critical of an indication as a smoke or fire warning. You see it you act on it.
However they were close in, setup for landing, and no other options and that warning just did not or would not and could not alter their plan. They had a plan to land and they were committed by that point. I take a concerned approach to their transmissions once both engines failed. Professional and extremely “normal” in tone. I don't know if one would expect anything else than that from a crew that is experienced as this crew was.
Finally I would say that if this theory proves to be the reason, aside from not knowing why the collector tank went dry, a lot of this will make better sense.
My feeling and what the evidence in a very limited way shows is first both engines quit, presumably simultaneously. I can only attribute lack of fuel to that as a “reasonable” contributing factor.
Both engines are fed by the single tank that has no quantity indicator. Instead it has low level warning annunciator. Probably red. From that indication to no fuel remaining in the collector tank would be in part determined by the combined fuel flow and possibly by either no fuel transferring or insufficient fuel flow from the main wing tanks. Either because they were empty or some other reason the fuel was not able to flow into the collector.
I would best say the annunciation of that Low Level does not leave the crew with much to go on unless they anticipated it because they initiated a flight with not enough fuel for the flight. If they were tankering extra then they had enough fuel and we go back to the low level in the collector tank. This should be as critical of an indication as a smoke or fire warning. You see it you act on it.
However they were close in, setup for landing, and no other options and that warning just did not or would not and could not alter their plan. They had a plan to land and they were committed by that point. I take a concerned approach to their transmissions once both engines failed. Professional and extremely “normal” in tone. I don't know if one would expect anything else than that from a crew that is experienced as this crew was.
Finally I would say that if this theory proves to be the reason, aside from not knowing why the collector tank went dry, a lot of this will make better sense.
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Interesting ww550. You could certainly make a case that they knew they were cutting it close on fuel, which was why there was so little surprise evident in the last transmission. Only time will tell.
Both engines are fed by the single tank
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This is a helpful post. I flew the 601-3A (actually the very first 601-3A delivered) for about 7 years. 3-5 times to Europe annually. I do not believe the collector tank is internally separated into left engine/right engine feed. For sure there are 2 separate fuel lines, actually 3 including the APU, from that tank to its respective engine but I believe the collector tank is but one tank feeding engines and APU. I could be wrong but that's how I recall it.
How would any aircraft meet the requirements of 14 CFR Part 25 with a single collector tank feeding both engines?
Each fuel system must meet the requirements of § 25.903(b) by—
(a) Allowing the supply of fuel to each engine through a system independent of each part of the system supplying fuel to any other engine; or
(b) Any other acceptable method."
25.903 -
"(b) Engine isolation. The powerplants must be arranged and isolated from each other to allow operation, in at least one configuration, so that the failure or malfunction of any engine, or of any system that can affect the engine, will not—
(1) Prevent the continued safe operation of the remaining engines; or
(2) Require immediate action by any crewmember for continued safe operation."
"§ 25.953 Fuel system independence.
Each fuel system must meet the requirements of § 25.903(b) by—(a) Allowing the supply of fuel to each engine through a system independent of each part of the system supplying fuel to any other engine; or
(b) Any other acceptable method."
25.903 -
"(b) Engine isolation. The powerplants must be arranged and isolated from each other to allow operation, in at least one configuration, so that the failure or malfunction of any engine, or of any system that can affect the engine, will not—
(1) Prevent the continued safe operation of the remaining engines; or
(2) Require immediate action by any crewmember for continued safe operation."
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From the 604 Operating Manual:
The 601 was the same, but that's not relevant to this thread.
FUEL TANK SYSTEM (CONT'D)
Components and Operation
Main Tank System
The left and right main tanks are integral-type fuel tanks (wet wings) that supply fuel to their
respective engines via two collector tanks. Flapper valves in the wing ribs prevent fuel from
surging toward the wing tips. The main tanks may be refueled by pressure or gravity. The APU’s
normal fuel supply is from the right main tank.
Collector Tanks
Two collector tanks, situated at the lowest point of the center auxiliary tank, are considered
part of the main tank system.
Components and Operation
Main Tank System
The left and right main tanks are integral-type fuel tanks (wet wings) that supply fuel to their
respective engines via two collector tanks. Flapper valves in the wing ribs prevent fuel from
surging toward the wing tips. The main tanks may be refueled by pressure or gravity. The APU’s
normal fuel supply is from the right main tank.
Collector Tanks
Two collector tanks, situated at the lowest point of the center auxiliary tank, are considered
part of the main tank system.
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I drove past the crash site yesterday. The pilots made the very best of a really poor choice of places to put it down. If the highway was as busy then, as it was today, it was great that there were no citizen injuries. Otherwise, maybe the golf course, but houses would have been in the path in any case. The concrete wall is still smashed, and well blackened. The highway shoulder pyloned off, but I did not see any slide marks in the pavement. A pile of contaminated soil is tarped by the side of the highway.
A bad situation, but could have been so much worse....
A bad situation, but could have been so much worse....
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As I see from your comments that the 604 and the 601 have the same design for the collector tank. If you know is there an associated EICAS message for low fuel in the collector tank(s)? As I know the Gulfstream 5 and 550 have such a warning. Now how would someone know which collector tank is "low"? I don't know.
I believe there may be some relevance if in fact both engines quit at the same time (some floating remarks about the possible inadvertent shutdown by one of the two pilots during the manipulation of flaps, etc) if it was in fact fuel starvation AND there was fuel remaining in the wing tanks, sufficient fuel. I did have a close friend with our local FAA (South Florida) tell me that there was a theory that in fact the control/thrust levers somehow travelled to the cutoff position. That would be significant if true obviously.
I believe there may be some relevance if in fact both engines quit at the same time (some floating remarks about the possible inadvertent shutdown by one of the two pilots during the manipulation of flaps, etc) if it was in fact fuel starvation AND there was fuel remaining in the wing tanks, sufficient fuel. I did have a close friend with our local FAA (South Florida) tell me that there was a theory that in fact the control/thrust levers somehow travelled to the cutoff position. That would be significant if true obviously.
One of the working theories that are floating around involves inadvertent activation of the fuel shut off/ cut off switches.
Either by RH pilot reaching under the thrust levers for the Thrust reverser switches or the LH pilot reaching under the thrust levers for the flap handle while power is reduced by the flying pilot.
Either by RH pilot reaching under the thrust levers for the Thrust reverser switches or the LH pilot reaching under the thrust levers for the flap handle while power is reduced by the flying pilot.
Last edited by B2N2; 27th Feb 2024 at 18:48.