18 May 2020

Out Of The Envelope (Update And Bump)

The Weber CL-41 seat in the CT-114 Tutor is not a modern, self-righting, zero-zero ejection seat.

In a level ejection you need 60 knots of airspeed and 60 feet of altitude minimum to even have a chance at a successful ejection.

This ejection was from a nose-down attitude and every part of that downward vector adds to the minimum altitude needed.

The rip-cord on the chute isn't pulled until seat separation is complete and that doesn't start until a full second after the seat clears the plane.  Then a drogue pulls the main canopy out of the chute pack then it inflates and the decent is slowed.

Video:



Two seconds after the seat clears you can just see the drogue pulling the chute out from the right-seater's pack.  There simply isn't enough time to get a chute left and she didn't make it.

Something else to consider is the design of this seat is from the 1950's.  First flight of the CT-114 is in 1960 and the last one rolled out the factory doors in 1966.  Seats were not designed for the weights of women back then.  They were designed for strapping young men of military age and fitness.

That Captain Casey was killed and the other crew member lived could very well be a factor of mass, despite being the first out of the plane.

She would have been ejected faster, thus being slower relative to the wind and that could have put the chute outside its opening envelope for too long to deploy before she hit.

Plus!  There's just no fucking excuse for Canada to still be using the 60 year old CT-114 when it's been replaced as an operational trainer by the BAE Hawk 115 (CT-155) and Beechcraft T-6A Texan II (CT-156 Harvard II) in 2000.

If it had been any other ejection seat equipped plane in the Canadian inventory; Capt Casey would be alive and Capt MacDougall would not be seriously injured.

Update:

It would appear that she was in the left seat, or the second one out, judging from how the plane with her name and PAO job is marked up.  That's a huge factor in surviving at low level.

More than a couple multi-crew aircraft have lost the last man out as a result of the seat sequencing.

I am not certain if the Tutor has automatic sequencing or if it's every man for themselves to pull their own handle.

I dimly recall a documentary about The Snowbirds where the pilot is explaining the ejection seats to the documentary narrator where the pilot says, "I will say eject, eject, eject, and you will pull the handles."  The narrator guy asks if he should confirm the command or something and the pilot replies, "If you even say, 'huh?' you're going to be talking to yourself."

That sort of implies that each seat needs to be fired by its occupant.

4 comments:

  1. That was... horrifying.

    And your analysis makes too much sense. Weight and drag from the body have a lot to do with the performance of older ejection seats, where it was not uncommon for a lighter person being injected to fire so quickly the canopy would still be in the way. And the force of firing a lighter person would cause the arms to flail sideways and rip the elbows off on the edges of the cabin.

    And... Yeah. Dangit. That would be like making the Thunderbirds still fly the (checking interwebs) F-84G (comparable aircraft - single engine, straight wing, early gen ejection seat (of which my father hated and was very happy not to have ever had to use.))

    If you're going to fly an exhibition team, your planes better be the best for the job, and the Hawk is probably one of the best modern trainer/exhibition class jets out there. Though the new Boeing/Saab T-7 Red Hawks are pretty nice, but not in service yet, especially with the Canucks.

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  2. I flew Tutors as a student back in the '90's, and you are absolutely right. I know five men who ejected from Canadian military aircraft, two of them died. Three of them ejected from Tutors, and one of those died. He was Capt. Mike VanDenBoss, who died while flying as a Snowbird.

    A couple of points about the seat. you are correct, there is no command ejection. Since the crew sits side by side, it is not required. Command ejection is to ensure that the front seat does not go before the back seat, and fry the backseat guy in the face with rocket blast. The A6 Intruder also did not have command ejection for the same reason. There is a paragraph in the manual about how to eject the other guy if they are incapacitated, but they will certainly be injured by windblast and flailing.

    Also, you could eject at zero altitude, but you had to be going over 90 knots. As the manual put it, the chute would inflate sufficiently to provide "..a survivable rate of descent.", but you would for sure break both legs since you would still have the seat survival pack attached to the back of your legs.

    I doubt the weight of the female crew member played much of a role. She would have been within the weight limit of the seat or she would not have been flying. She was just too low with too much down vector. In fact, I am surprised that both of them weren't killed. In fact the seat has the opposite problem. Men today are bigger and heavier than they were in the '50's and the survival kit had to be modified to reduce the weight and even then there is a restrictive max weight for male pilots.

    The big problem is exactly as you described. You wear the parachute. In modern seats, the seat is built into the seat, it deploys, the seat is cut away from you and falls away from you. In this old system, you wear the chute. After ejection, a gas generator blows open the seat harness, and rolls a reel which tightens a strap running down the back of the seat. This kicks you out of the seat, and pulls the pin on the automatic opening device on your chute. This adds a couple of seconds to the time, and if you eject too low, too slow, or with too much down vector, the seat can fall back onto you, just as your chute is deploying. This is what kills most people unsuccessfully ejecting from a Tutor.

    Best regards,

    Paul from Canada

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  3. Also, looking at the footage, it looks like a classic engine failure/loss of thrust, and the pilot follows the memory item procedure. ZOOM--IDLE-AIRSTART. Immediately trade airspeed for altitude. Reduce the throttle to idle, which may immediately clear a compressor stall or surge, and is also step one in the re-light procedure, and hit the AIRTART button, (conveniently located on the throttle right by your thumb), which turns on continuous ignition.

    Once that is done, assess. If on fire, eject immediately! If not and time/altitude permits, attempt a re-start, if not, eject. If you are close enough to the field, you could also try a dead stick landing. At Moosejaw, we had a table to memorize of DME vs. altitude. If above X thousand feet at Y DME to the field, you could safely glide back to the field if you followed a specific flight profile, or if you fell below it on the way back, you would at least eject closer to base.

    It looks like he also tried to turn back to the field. Normally in a single engine aircraft this is discouraged, as the chance of a stall/spin in the turn is high and you are too low to recover. In this case it makes sense. I have flown into YKA, and I know they were departing down the valley towards downtown. Turning back meant a crash/ejection either within the airport perimeter, or up the valley away from town.

    The normal break approach and landing in a Tutor is to fly over the button of the runway at (IIRC), 1'000 AGL, and do a 60 degree bank, 2G, 360 degree turn, which would have you roll out on short final, on speed. So turning back downwind would give him a safe landing if he reached the approach end of the runway at 500 AGL, which he night have been able to do.

    Unfortunately, at the end of the 180 zoom climb,the aircraft departs from controlled flight, and the command to eject given, but by the time they leave, the plane has nosed over, and there is too much down vector. The question for the investigation is why the engine lost thrust, and why the plane departed controlled flight. Did the pilot let the airspeed decay too much? Or did the engine failure possible damage a control rod or cable?

    Paul from Canada

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