Light aircraft down near McKinlay, Qld
I wouldn’t have thought that it would have a complex pressurisation system, so I’d expect that even if they didn’t set the pressurisation to go back up to F280, all that’s going to happen is it’s going to hit max diff and open the safety valves to maintain max diff. The cabin isn’t going to magically depressurise because it wasn’t set to climb back up to F280.
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With one engine out, feathered or not at the stall it's still going to roll on its back.
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So let’s wait for the investigative body to do its job and report its findings. That’s how many years? I’m not saying let’s just come to our own conclusions, but it’s healthy to discuss these things post events, it will be a while before we get actual answers, the time taken by investigating bodies to provide the industry with answers, let alone reform, is unacceptable as many know, and as many training departments know.
My previous employer lodged a complaint with the body for the time it took to report on an incident, the time that passed without any information provided to the business and also the failure to disclose during the multi year wait, key findings which they advise they will release of safety is at risk during the investigation period.
Was a chap on here not that long ago that picked up an issue with his aircraft because of people actively taking about it on here.
Last edited by PoppaJo; 5th Nov 2023 at 17:52.
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This series of aircraft have quite nasty stall characteristics. It will flick into a spin in the blink of an eye.
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So I went back a little bit to look at some previous flights, and there's one on the 24th October, Toowoomba-Isa with a virtually identical vertical profile, in a similar geographic area. When you factor this second flight in, it does look like the descent from cruise altitude wasn't as a result of a problem or troubleshooting, but part of their normal operations. Whether such a descent could result in 'forgetting to reset' a pressurisation controller that might explain the final few minutes, I'll leave to someone actually rated on the Commander.
The accident flight.
And one a week earlier over the same route.
The accident flight.
And one a week earlier over the same route.
Clearly there are misconceptions around these issue and I think it's healthy to discuss it from a learning perspective. People do learn things here you know.
One of my personal favorite training exercises is a flame out in the cruise at max cruising altitude and watch it unfold, usually takes about 50 seconds while the pilot is distracted with engine instruments and checklists. For sim instructors do this with motion "off "
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remember the Paine Stewart Lear 35 accident
I would revisit pressurization if the aircraft had long since passed it's descent point and there was no radio transmission.
I wouldn’t have thought that it would have a complex pressurization system, so I’d expect that even if they didn’t set the pressurization to go back up to F280, all that’s going to happen is it’s going to hit max diff and open the safety valves to maintain max diff. The cabin isn’t going to magically depressurize because it wasn’t set to climb back up to F280.
I'm also still struggling to see a structural failure element in this. If a wing separated or deformed I can't see how the autopilot managed to keep it straight and level until it basically stalled, if the pilot was flying why did they not initiate a descent to keep speed up to maintain control. None of this fits with a structural failure, more a loss of power that led to speed loss and departure from controlled flight when it reached near the stall.
Last edited by 43Inches; 5th Nov 2023 at 20:24.
Xeptu;
Thanks indeed for your response. Been there/done that/seen that too!
What I was querying was if the Commander 1000's stalling characteristics are any better or worse than comparable types at similar altitudes. "illusion" states that they're worse - I was wondering just where that came from...
Thanks indeed for your response. Been there/done that/seen that too!
What I was querying was if the Commander 1000's stalling characteristics are any better or worse than comparable types at similar altitudes. "illusion" states that they're worse - I was wondering just where that came from...
The autopilot will hold all the way to stall warning, albeit with significant aileron roll input and some roll towards the dead engine. It will automatically disengage at stall warning, usually followed by a rapid roll towards the dead engine.
In my experience for the ones we deliberately don't brief first action, which is initiate a drift down aiming for 150kts, and at least point towards a suitable airport, so it's altitude select, just spin it down, IAS, rudder trim, then take action. For the ones that know everything and need a fright.
The unbriefed ones it goes something like this, flame out, eyes on engine instruments, look out the window to see if there's something to see, reach for the checklist, at which point the autopilot disengages followed by a snap roll toward the dead engine.
The end result, the prop was never feathered, the maximum speed was exceeded by around 40 kts at exercise termination. SIM ONLY of course.
In my experience for the ones we deliberately don't brief first action, which is initiate a drift down aiming for 150kts, and at least point towards a suitable airport, so it's altitude select, just spin it down, IAS, rudder trim, then take action. For the ones that know everything and need a fright.
The unbriefed ones it goes something like this, flame out, eyes on engine instruments, look out the window to see if there's something to see, reach for the checklist, at which point the autopilot disengages followed by a snap roll toward the dead engine.
The end result, the prop was never feathered, the maximum speed was exceeded by around 40 kts at exercise termination. SIM ONLY of course.
Xeptu;
Thanks indeed for your response. Been there/done that/seen that too!
What I was querying was if the Commander 1000's stalling characteristics are any better or worse than comparable types at similar altitudes. "illusion" states that they're worse - I was wondering just where that came from...
Thanks indeed for your response. Been there/done that/seen that too!
What I was querying was if the Commander 1000's stalling characteristics are any better or worse than comparable types at similar altitudes. "illusion" states that they're worse - I was wondering just where that came from...
P.S I didn't say that right, I meant out of the beta range, as the aircraft approaches the stall the aerodynamic assistance lets call it on the prop is reduced, which leads to higher dependency on the NTS system and it's not great. If the prop goes beta at the stall your on your back in a nano second.
Xeptu, correct me if I’m wrong..it’s been 40 years since I fiddled with a 331.
My memory of the NTS system is that it cycles the blade angle between feather and some other blade angle to minimise drag - where drag is the condition when the airflow is driving the engine.
The idea being that this feature buys the pilot time to recognise the failed engine and feather it.
I don’t understand how NTS, if working as intended, would flip anything on its back anymore than say stalling an aircraft with the operative engine producing power.
Is it possible that the fidelity of the simulator in question may be lacking at that extreme corner of the envelope?
My memory of the NTS system is that it cycles the blade angle between feather and some other blade angle to minimise drag - where drag is the condition when the airflow is driving the engine.
The idea being that this feature buys the pilot time to recognise the failed engine and feather it.
I don’t understand how NTS, if working as intended, would flip anything on its back anymore than say stalling an aircraft with the operative engine producing power.
Is it possible that the fidelity of the simulator in question may be lacking at that extreme corner of the envelope?
Xeptu, correct me if I’m wrong..it’s been 40 years since I fiddled with a 331.
My memory of the NTS system is that it cycles the blade angle between feather and some other blade angle to minimise drag - where drag is the condition when the airflow is driving the engine.
The idea being that this feature buys the pilot time to recognise the failed engine and feather it.
I don’t understand how NTS, if working as intended, would flip anything on its back anymore than say stalling an aircraft with the operative engine producing power.
Is it possible that the fidelity of the simulator in question may be lacking at that extreme corner of the envelope?
My memory of the NTS system is that it cycles the blade angle between feather and some other blade angle to minimise drag - where drag is the condition when the airflow is driving the engine.
The idea being that this feature buys the pilot time to recognise the failed engine and feather it.
I don’t understand how NTS, if working as intended, would flip anything on its back anymore than say stalling an aircraft with the operative engine producing power.
Is it possible that the fidelity of the simulator in question may be lacking at that extreme corner of the envelope?
In flight when you reduce to flight idle thus reducing blade angle toward fine, the NTS senses if the blade angle has gone too far and directs oil pressure to the hub to coarsen the blade angle in order to keep it in the flight range. A light for each propeller illuminates to warn you that the NTS system is sensing negative torque and is doing its job.
Does that explain the system without getting too technical.
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Is it possible that the fidelity of the simulator in question may be lacking at that extreme corner of the envelope?
I just find it sad the crap that is posted here after every accident. Let the authorities deal with it and stop the one-upmanship.
People.....pilots want to work out what happened, for a number of reasons. So they can learn from it, so they can design training scenarios. If it happened once, it can happen again.
Another factor, let the authorities deal with it? We're talking about the ATSB here, the organisation of 3 year investigations. What do you expect pilots will do? Sit around and wait 3 years?
You've been a member of this bulletin board for quite some time. You should be able to work out which comments are worth reading and vice versa.
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A couple of factors at play here, human nature being the strongest factor. Whether you like it or not, people speculate. If you don't like it, don't click on the thread, you know what will be in here.
People.....pilots want to work out what happened, for a number of reasons. So they can learn from it, so they can design training scenarios. If it happened once, it can happen again.
Another factor, let the authorities deal with it? We're talking about the ATSB here, the organisation of 3 year investigations. What do you expect pilots will do? Sit around and wait 3 years?
You've been a member of this bulletin board for quite some time. You should be able to work out which comments are worth reading and vice versa.
People.....pilots want to work out what happened, for a number of reasons. So they can learn from it, so they can design training scenarios. If it happened once, it can happen again.
Another factor, let the authorities deal with it? We're talking about the ATSB here, the organisation of 3 year investigations. What do you expect pilots will do? Sit around and wait 3 years?
You've been a member of this bulletin board for quite some time. You should be able to work out which comments are worth reading and vice versa.
One great thing about pilots in general is that most want to learn from other pilot’s experiences no matter how good or bad, unfortunately in most cases the trigger is accidents or serious incidents.
As far as accident reports go, some are good and others are completely inaccurate usually due to inexperienced investigators or influence from stakeholders external to the investigation authority.
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