Originally Posted by
Squawk7700
The stec autopilot in the early Cirrus doesn’t have a IAS hold as it uses vertical speed. Speed could decay away as the altitude increases, which it doesn’t really, so it’s performing well with 315 hp.
The profile appears to be a consistent climb to max altitude at what is probably the best rate you could get out it is, on the way to the pilots alleged preferred 10,000ft. The airspeed is low though… it’s a lowish speed with a high climbing angle into thinning air. If there was in fact ice building up, it’s building up on the underside of the wing, MU2 style. Add this to the laminar flow Cirrus wing at high angle of attack and when the wing drops, it will drop hard, potentially inverted.
We all know that a Cirrus isn’t getting out of a spin with no chute and I wouldn’t be at all surprised if nobody was able to pull it.
Of course this would all be pending icing levels and cloud at the time….
On the flip side an incapacitated pilot scenario with 10k in the STEC in non-icing conditions doesn’t immediately result in this scenario either. For a passenger to turn off the auto pilot they need to press any hold the button on the controls for a couple of seconds and hear the loud beeps first. Seems somewhat unlikely.
.
Another couple of myths that needs busting. A Cirrus in a spin can be recovered from the spin using standard technique - throttle idle, ailerons level, stick forward, rudder against the direction of rotation until the spin stops. Then recover. When designing the SR series, the manufacturer offered the chute as an "alternative means of compliance" which is why it was never tested in US and the myth was born. However in EASA land, they refused to accept this AMOC and had the aircraft spin tested in various configurations - tail heavy, nose heavy etc - and recovery from a spin was normal.
Secondly, I did repeated stall exercises in the Cirrus which never dropped a wing. If you were flying straight and level and kept pulling back, the plane would violently shake but you still have aileron authority, you can keep the plane descending, stalled, wings level because of the cuffed wing profile which means that the outboard area of the wing where the ailerons is, remains unstalled. Only if you introduced yaw would it drop but was then easily recovered with rudder application.
As for the comment about needing to hold the autopilot button for a couple of seconds, that's also incorrect. A quick press of the button and the autopilot is off. In fact, depending on how it's been configured, if you hold the autopilot button for a couple of seconds, you can cause it to enter CWS mode - which means the aircraft will be commanded to hold it's current attitude - ie, nose angle, wing angles.
The fact remains that the aircraft wasn't flying on autopilot - too many variations in heading for it to have been active and, as previously said, for a pitch mode to be active, a roll mode needs to also be in use, which wasn't.
Originally Posted by
Lead Balloon
As 43” observed:Here’s an example where an aircraft ‘landed itself’ with the pilot unconscious, and the pilot survived: https://youtu.be/MfzfP5CZBj8?si=Ew2Lag-ElRyCfYRM
So no doubt there are examples of aircraft plummeting to the ground due to pilot incapacitation, but there are many more examples where that doesn't happen. And there is a particular characteristic of the Cirrus that is relevant here.
Thank you for your very considered and informed post, FMJ.
Rest assured: I understand that all sorts of ostensibly healthy people collapse and die, unexpectedly, of some undetected affliction. The only pilots I know who’ve died unexpectedly at the controls were the holders of Class 1 medical certificates (thus exposing the expensive Avmed façade for what it is).
With your first-hand experience in the ergonomics of a Cirrus cockpit, could you please expand on how a pilot of a Cirrus "slumps across the controls, locking them"? Exactly what bits of the pilot’s body end up where, and how does that happen despite the shoulder harness?
Have you had a look at the CAPS Event database to which I posted a link earlier in the thread? There are numerous events – and of course numerous events not involving Cirrus aircraft – where no mayday is transmitted by a conscious pilot who’s busy on higher priorities. Did you note the events of ‘unilateral’ deployment attributed to static electricity?
I do think you might have misinterpreted what some of the reported parameters mean as to airspeed versus rate of climb/descent. My theory is based on discussions I’ve had with people who understand the numbers and the Cirrus – and some comments made here – which suggest a near-vertical descent but with some kind of unusual drag … like an aircraft with parachute lines tangled around the fuselage and tailplane and the parachute barely able to inflate. My comment about the comms antenna was the result of the physical characteristics of the Comm 1 antenna compared to other antennae in that scenario. But of course we don’t know if the pilot even tried to transmit a mayday.
Earlier in this thread reference was made – correctly - to the probability that the aircraft “would have just had it’s second 10 year chute re-pack completed”. As soon I read that, I consider the risk of maintenance induced failure. The flight I fear most is the first one after my aircraft has been the subject of mandated meddling. There have been many creative attempts made on my life by LAMEs over the years – not deliberate I hope. But the fact is: people make mistakes. It will therefore be important for the ATSB to investigate the maintenance history of the CAPS in particular.
Hopefully the ATSB folk will be able to ascertain at least whether the CAPS was deployed or not. Given the location, I would be surprised if there were no eye witnesses of even a couple of seconds of the descent. You will see, from the events database, that in one tragedy arising from icing the empty parachute was seen descending minutes after the aircraft impacted the ground. If this aircraft’s parachute is found intact some distance from the impact site, that would be a ‘lay down misère’ on a number issues.
Firstly, when talking about a pilot slumped across the controls, I was referring to non-Cirrus aircraft. No way an incapacitated pilot can block controls on a Cirrus. Secondly, as an ex Cirrus owner and ex member of COPA, I would read everything I could about incidents in order to learn from them. The uncommanded initiation of CAPS was caused due to electrical interference which lead to a change in the systems - this was maybe 6 or 7 years ago so I very much doubt that could repeat itself, especially as this aircraft would have had CAPS refitted a year or so ago.
Whilst talking of the refitting, it's something that the maintenance operators have experience with, so no big deal. I also recall the SB to check the propellant because some got wet....
I also participated in CPPP trainings and let's take your example of an uncommanded parachute deployment - once the chute has been deployed, you are no longer in command of the aircraft, so what would you, as pilot at 9500feet do? Right. Call up and say what's what, let people know where you are in case you land in trees or something, just get the emergency services moving.
Let's now go with your thought that maybe the chute deployed erroneously, due to MIF, was incorrectly deployed wrapping itself around the aircraft - the aircraft became uncontrollable and the pilot was looking to regain control somehow hence he was more concerned with aviate than communicate. Reasonable assumption, but the reality is BRS systems are fitted in thousands of aircraft globally and for one to first self deploy and then mis-deploy is unheard of. As you can see, you need an erroneous deployment of the chute AND a misdeployment of the chute for that scenario to occur. That aircraft had been flying frequently after the repack so I'm pretty sure that a MIF can be ruled out.
Let's reduce this to a minimum - let's say he had commanded CAPS deployment and it mis-deployed. Why would he do that? First, there seems to be a myth that Cirrus pilots will, without hesitation, pull the chute at the first sign of trouble. That's not true. At 9500 feet you have a lot of time to trouble shoot, say, if you have engine issues; you will first check the usual suspects - fuel, air, spark - before looking for a suitable location and, if none available, then consider deploying CAPS. No Cirrus pilot would pull at 9500 feet unless he'd totally lost control, had structural failure and saw no way out which is why I'd rule both a commanded and uncommanded deployment of CAPS out.
Originally Posted by
Lead Balloon
On the specific issue of no radio call, there are plenty of emergencies during which a conscious pilot does not transmit a mayday. There is, after all, that ‘aviate, navigate, communicate’ list of priorities.
The aircraft involved in this tragedy was less the 20nms from YSCB, in CTA, on primary and secondary RADAR being monitored by ATC. What, precisely, would a mayday call have achieved? Do we think ATC would, absent a mayday or 7700, watch the aircraft suddenly descend, without clearance or any communications, and shrug and assume that there was no problem? The data indicate a descent from around 9,000’ to around 3,000’ – that’s nearly ground level around the area of impact – in about a minute. I doubt whether I’d spend that time transmitting information to ATC, when I know that they are seeing what’s happening anyway.
On the specific issue of "no CAPS", we don’t know that the pilot didn’t try to deploy the CAPS. Maybe the pilot tried but the system malfunctioned. Maybe the CAPS was deployed but at too high a speed. Maybe the CAPS was deployed while the aircraft was inverted or in some unusual attitude that resulted in the parachute lines being fouled by the airframe and the parachute not working properly or at all.
Yep.
Firstly, on the one hand you're hypothesising that the CAPS system deployed without command and then you're suggesting that the pilot tried to deploy it but it failed. If I was still a Cirrus owner, I'd be very worried about such theories because we buy the aircraft because of the additional safety offered by the BRS..... If BRS was so unreliable that it "might" ignite itself without command but then, when required, "might not" ignite, I doubt we would be paying so much for such a system, agree? BRS has a proven track record when operated within its parameters. And the data point before the upset showed a cruise climb of around 120KIAS, 15 seconds later they were dropping at 3700fpm at 90KIAS which means it wasn't deployed at too high a speed.
Secondly, a mayday call will always alert ATC as to what is going on, they can offer advise as to nearest airfield if necessary and raise awareness of ground units. Thirdly. how does a plane suddenly become inverted? Without external intervention? For me, his flight path is indicative of a pilot hand flying with the plane trimmed for cruise climb. If, as you hypothesise, he pulled the chute whilst inverted, how did he become inverted? I've flown through enough clouds to know that although they can be bumpy, they're not going to throw you on your back; the pilot was both experienced and current enough to know what he was doing. In order for that theory to be correct, something else had to have happened first, throwing the plane on its back. And knowing that the flight was in and out of some pretty heavy clouds with the freezing level in the clouds, I'd go with that. The plane iced up, stalled, descended like a brick. Nothing to do with CAPS.
But that doesn't explain why no recovery was initiated. Which can be answered by Occam's Razor. No recovery was initiated because the pilot was incapacitated. That's no negative inference on the pilot, it's just something which fits the story with the minimum number of external requirements....