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-   -   Crash at SunShine coast. (https://www.pprune.org/pacific-general-aviation-questions/641219-crash-sunshine-coast.html)

djpil 14th Aug 2022 07:38


Originally Posted by MagnumPI (Post 11278044)
Serious question, please don’t shoot me down. I’ve been considering doing an aerobatics endo, does anyone use parachutes? Is it common or practically unheard of except in competitions and the like…?

Depends on what aircraft you do the spin/aerobatic endorsements in and where. I guess that the majority do not use parachutes in basic spin/aerobatic endorsement training.
If you are going to wear a parachute you need adequate training in its use plus the discipline of using it as briefed. Egress procedures must be rehearsed every flight.
To avoid jumping out of a perfectly good aeroplane then you would need to do the training exercises high enough above your hard deck. Hard deck consideration needs to consider the type of aircraft and the time required for two people to get out.
Read the article on page 7 here https://www.iac.org/files/magazines/SA_2011_05.pdf
In a Decathlon the instructor has to get the student to eject the door, student to get out first and then the instructor - that can use up a lot of altitude. I am aware of two fatal acccidents where parachutes have been used - in both cases only one person got out and the other did not.
In something like a Pitts my briefing is something like: I will say "bail out" three times and on the third time I won't be there. I am aware of fatal accidents where there had been sufficient height but the pilot left the decision too late.
Another consideration is weight and CG. Most aerobatic aircraft are fairly tight for useful load and some can be tight for loading within the allowable CG range.
Pay your money and take your pick.
https://www.airshows.aero/GetDoc/1470

Lead Balloon 15th Aug 2022 09:54

You’re special, 43”:

There's also no evidence to state they didn't try the POH recovery first either. So it's pure speculation that the accident is the result of MB or PARE technique.
So you interpret evidence of what people were briefed as being the 2 techniques that would be tried during a flight as being completely irrelevant to the question as to whether a 3rd technique was tried first?

In your vast experience of intentional spinning, on how many occasions did you take out the POH during flight to brief yourself on what it said about recovery, as your first preparation for the event?

43Inches 15th Aug 2022 10:36

I think your the special one here leadie. Theres no hard evidence what technique was employed. You are just making yourself look argumentative and trolling with such an attack, I do pity your feeble existance that you try to belittle those you disagree with. Or were you present or have a copy of the CVR fron this incident? Or do you want to continue with the line that its absolutely certain what happened here? Iam truely interested in how you are so certain that the loss of control is difinitively because of the recovery technique, or do you agree that its just a likely scenario?

Lead Balloon 15th Aug 2022 10:41


Originally Posted by 43Inches (Post 11278716)
I think your the special one here leadie. Theres no hard evidence what technique was employed. You are just making yourself look argumentative and trolling with such an attack, I do pity your feeble existance that you try to belittle those you disagree with. Or were you present or have a copy of the CVR fron this incident? Or do you want to continue with the line that its absolutely certain what happened here? Iam truely interested in how you are so certain that the loss of control is difinitively because of the recovery technique, or do you agree that its just a likely scenario?

Quoted just to make sure there’s evidence of what you originally posted.

QED.

43Inches 15th Aug 2022 10:56

My original post was stating that we have no firm idea what actually happened here. The statement that they could have even tried the poh technique, that was not my determination of what happened, just a slight possibility. We have no idea what the instructor knew, he may well have read the POH technique, we dont know. It may have been employed too late to effect recovery. There is no hard evidence at all apart from the flight path indicating a descent path consistant with the spin sequence and a failure to recover.

43Inches 16th Aug 2022 09:05

You do realise that this is a statement from the ATSB report;


The ATSB was unable to ascertain which of the recovery technique(s) was being utilised at the various stages of the spin recovery preceding the accident. For this reason, the ATSB was unable conclude if the use of an inappropriate recovery technique contributed to the accident.
and


Although the reason for the accident could not be fully established, the investigation identified that one of the spin recovery methods that was to be practiced on the day of the accident would most likely not recover the Cessna A150M Aerobat from a spin
Which is important to recognise that we have no conclusive evidence of what exactly caused this accident. The ATSB report is written to highlight the issues withe MB techniques when applied to the A150 and that pilots should seek guidance on a particular type prior to conducting spinning exercises.

I'm not sure what tangent you two are going off on but the important issue here is that spinning an A150 is not straight forward, and even with POH recovery technique the recovery can take time and seem futile until it works. So therefore it is plausible that the instructor may have tried the A150 technique too late in the piece to have recovered or possibly something else complicated the recovery, we just don't know. The briefing is just what the instructor expected to happen, as they were exploring the two generalised spin recoveries, that does not mean he was unaware of the A150 recovery technique, however it is also highly possible he was not etc etc....

Now it is most likely that what was briefed was practiced, that is the MB recovery was demonstrated, didn't work, then the extra time taken to recover led to insufficient height to pull out. But it is just the most plausible scenario, not an actual statement of fact.

On the previous event reported in CYO the correct POH recovery was attempted and the sequence almost ended in the same result, so while its easy to say the MB and PARE did not work, it also seems previously the pilots were almost killed when using the POH recovery. Why is that important? so that anyone who intends to spin A150s should be very cautious about it, and not just feel safe that they are not using the MB technique, lest we end up having the same conversation again when another spin exercise goes wrong. It might be found one day that a particular fuel quantity stabilising in the spin at a specific weight and CoG even within limits might have a nasty bite, who knows.

I was never questioning the ATSB report or its findings.

Squawk7700 16th Aug 2022 09:10

Sounds like a law suit in the making.

Lead Balloon 17th Aug 2022 01:07

We should be thankful to 43” for his masterclass in what constitutes evidence and the different standards of proof that apparently apply here:


There's “no evidence”.

It's “pure speculation” that the accident is “the result” of the MB or PARE technique.

It’s “just a possibility”.

There’s “no hard evidence”.

Do you want to continue with the line that its “absolutely certain”.

How are you “so certain” that the loss of control is “difinitively because of” the recovery technique.

We have “no conclusive evidence” of “what exactly caused” this accident.

It is “plausible” that the instructor “may have” tried the A150 technique too late in the piece to have recovered or “possibly something else” complicated the recovery.

It is also “highly possible”.

It is “most likely” that “what was briefed was practiced”.

It is just “the most plausible scenario”.
Only a formidable mind could reconcile the simultaneous assertions that:

- It is most likely that what was briefed was practised, that being the most plausible scenario, and

- Any suggestion that what was briefed was practised is pure speculation supported by no evidence.

There is actually evidence, admissible in civil proceedings at least, as to what happened. There is a human being who can give first-hand evidence of what was briefed. There are written notes taken by both 'students'. Where do you think the ATSB got this from:

One of the students indicated that, during the pre-flight briefing, they were not instructed on what recovery method was recommended in the Aerobat Pilot’s Operating Handbook (POH), or that it closely aligned with the PARE method. Further, they were instructed on the advantages of the Mueller/Beggs method, but not on its limitations; namely, if the Mueller/Beggs method was utilised on an Aerobat, the aircraft would not recover from a spin to the left (see Aerodynamic spins).

Both students were instructed to write down the 2 spin recovery methods on a piece of paper for reference in flight when the practical component of the spin recovery was to be undertaken. One of the students indicated that they believed they were going to utilise both methods of spin recovery during their flight instruction. The first method written down on both students’ spin recovery notes was the Mueller/Beggs method.
And the applicable standard of proof is not “certainty”. If a civil court finds, as you have found 43", that it is most likely that what was briefed was practised, that’s what the court will find happened in fact. That’s how standards of proof work. Your “most likely” far exceeds the “balance of probabilities” threshold.

The ATSB used the word “ascertain” for a reason. Of course it could not find out what happened “with certainty”. (Then there’s the “fully established” nonsense, which was ATSB’s attempt to say “ascertain” again…) ATSB does not investigate by reference to standards of proof. It leaves that to courts. You should, too, 43".

43Inches 17th Aug 2022 01:31

Leadie, thanks on that drivel you have written but it holds zero relevance to this thread and just makes you look like a legalistic pedant when I'm trying to promote a safety message here... If you want to belittle me PM me all you want, but dont waste the readers time with your ****e personal attacks.

Lead Balloon 17th Aug 2022 02:21

Your "safety message" seems to me to be that the most likely cause of this accident - supported by the available evidence - is just pure speculation. I disagree. And plenty of us have already written in our Big Book Of Aviation Wisdom that it's very important to understand the specific characteristics, systems, procedures and limitations (and 'odd quirks') of the specific aircraft we're flying from time to time.

43Inches 17th Aug 2022 02:27


Originally Posted by Lead Balloon (Post 11279798)
Your "safety message" seems to me to be that the most likely cause of this accident - supported by the available evidence - is just pure speculation. I disagree. And plenty of us have already written in our Big Book Of Aviation Wisdom that it's very important to understand the specific characteristics, systems, procedures and limitations (and 'odd quirks') of the specific aircraft we're flying from time to time.

Actually its to highlight that in addition to the MB and PARE techniques the A150 is still difficult to recover using POH technique and is unusual in this way. Therefore anyone considering spinning this type should be careful about a number of factors, not the least weight and CG position.

Hence why I harped on the fact that this might not be related to MB technique, although on balance of surrounding circumstance it most likely started with a MB demo. Why they didn't recover is more likely not understanding how long the aircraft takes to recover using any technique.

BTW I've know students who have spun training aircraft on purpose during area solo, one even filming themselves and posting it on youtube. So education on the dangers of spinning is not just for advanced aerobatic pilots reading this.

Lead Balloon 17th Aug 2022 02:31

Those are important and valid points. It would be helpful if you could always express them that succinctly.

djpil 17th Aug 2022 07:10


Originally Posted by 43Inches (Post 11279800)
Actually its to highlight that in addition to the MB and PARE techniques the A150 is still difficult to recover using POH technique and is unusual in this way.

In some spin modes it demands the correct application of the POH method. It is not difficult

Cessna especially emphasises even slight aileron deflection, leaving some power on, moving elevator before rudder, slow rather than brisk movement of the elevator.

There are other types which also demand, in some spin modes, correct application of the method in the POH. I had a scare in a Pitts S-2A (in the days before we knew about Beggs-Mueller) when it wouldn't recover from a spin after I'd delayed my normal control actions finishing a lomcevak. The S-2A in a power off spin to the right where outspin aileron is held to flatten the spin will not recover when aileron is neutralised using "normal spin recovery technique" according to the factory. They discovered this in 1980 and added an extra cockpit placard: "For flat spins use aileron with the spin for recovery". That placard hadn't long been in the aeroplane when I needed to know about it. I quickly considered what was going on and then fixed it.

Read Brian Lecomber's magazine article and his delayed spin recovery in an Extra 230. Read Dave Mond's article about his delayed spin recovery in a Pitts S-2B. Read the ATSB's accident report on VH-UPB for the Chipmunk spin saga 60+ years ago. Over the years I've had a number of spin instructors tell me about delayed recoveries in a Decathlon and I ask about their recovery technique - invariably I respond with "you were lucky that you didn't die" and refresh them on the correct recovery method amply described in the manuals.


Originally Posted by 43Inches (Post 11279800)
... should be careful about a number of factors, not the least weight and CG position ...

Inertia is related to those parameters but is a separate parameter. Cessna has noted "Distribution of the weight of the airplane can have a significant effect on spin behaviour. The addition of weight at any distance from the center of gravity of the airplane will increase its moment of inertia about two axes. This increased inertia independent of the center of gravity location or weight will tend to promote a less steep spin attitude and more sluggish recoveries." e.g. extra fuel will increase both roll and yaw moments of inertia. They are second moments (the moment arm squared) so there is a bigger change to the moments of inertia than CG for changes along the fuselage centre-line, even more so with tanks in the wing.

It is worth recalling this text from the FAA's Flight Instructor Bulletin #18: "The subject of airplane spinning is a complex one, which is often over-simplified during hangar-flying sessions. ….. This has resulted in some confusion and misunderstanding over the behaviour of airplanes in spinning flight, and it appears this lack of understanding may have contributed to some serious accidents. …" from 40+ years ago.


By George 17th Aug 2022 09:54

Shame the post descends into a slanging match as it is not only a interesting subject but one where there is a strong safety message. Lead Balloon and Djpil have hit the nail on the head. ‘Know your aeroplane, the POH and any peculiarities to spin recovery for the type’ one size does not fit all.

I have spun half a dozen different types, the only classic one is the DH82, textbook spin recovery. The Chipmunk, after opposite rudder, requires the stick full forward to the stop and some even speed up one more turn before recovery. They also will go flat with an aft C of G , for example a light weight in the front and a NRL player in the backseat. The Victa Airtourer will stop spinning with central rudder. All are slightly different in some way.

I know of one instructor killed in a Grumman AA1 where the fuel contained in a tubular spar runs to the wingtips and stabilises the spin. Then you have some of these RAA machines with very dubious spin qualities.

I think it was a mistake to remove spinning from the syllabus. I understand the theory was, it is dangerous. This accident I guess proves that point.

What is dangerous is not knowing your aeroplanes capabilities.

43Inches 17th Aug 2022 10:33

As far as I know these peculiarities were limited to the A150, does it still apply to the C152A? I recall most of the recovery 'horror' stories being in the 150.

djpil 17th Aug 2022 23:40


Originally Posted by 43Inches (Post 11279979)
As far as I know these peculiarities were limited to the A150, does it still apply to the C152A? I recall most of the recovery 'horror' stories being in the 150.

Perhaps because the FAA and Cessna took action with their publications and flight instructor seminar summarized in magazine articles - so a lot of publicity about it in the mid-late '70s. The NTSB commented: “Detailed investigation by the FAA, however, disclosed that problems were related to operational vagaries or anomalies, inadequate knowledge regarding the precise spin recovery procedures for the aeroplane, improper application or misapplication of recovery controls, apprehension, and confusion." The Cessna document is readily available free online. The 152 is very similar but a more forward CG and heavier so higher moments of inertia in pitch - more difficult to positively enter a spin. Kershner confirmed that the 152 Aerobat responds to Beggs-Mueller technique exactly the same as the 150. Kershner has two books which have detailed information about spinning (especially) the Cessna, it should be a reference for all who instruct on the type.
https://cimg0.ibsrv.net/gimg/pprune....a22e372dff.jpg
https://cimg9.ibsrv.net/gimg/pprune....7930cf7e50.jpg
Note that demo of a hands off recovery after 2 turns - Kershner also demonstrates that once it gets to 2 1/4 it will not however when it gets to 4 turns it may do so - just those two points in the spin for that one particular example. People hear that comment about a hands off recovery being demonstrated so the misinformation spreads.

MagnumPI 17th Aug 2022 23:45

From your username, I'm wondering if you're David Pilkington? Much respect for your contributions in this thread and patient explanations. Might have to come down to MMB and do my endorsement with you!

43Inches 18th Aug 2022 00:29

It does sound like a lot of this well documented knowledge on type has been lost in history with it being past down haphazardly by knowledgeable aerobatic instructors. I never taught aerobatics and spin training was part of my instructor rating and can not remember at any point having these discussions. Which is why I'm trying to prolong this discussion so others can share more information like djpil has provided.

I'm in 100% agreement with the 'know your type' mantra, but this is beyond what I consider normally available knowledge for the type. The POH recovery technique does not go into details such as djpil has provided and it's clear there's a few little tricks that can be employed in addition to the POH list that can be thrown in.

The ATSB statement that pilots should seek additional instruction as per Cessnas' advice is very pertinent in regard to these aircraft, or any aircraft you should intend to spin, even if its a variation of a familiar type.

As an aside, is it required for the spin recovery technique to be placarded in such aircraft?

I think a lot of this is still around today from what I've heard over the years regarding recoveries in 150/152s...


“Detailed investigation by the FAA, however, disclosed that problems were related to operational vagaries or anomalies, inadequate knowledge regarding the precise spin recovery procedures for the aeroplane, improper application or misapplication of recovery controls, apprehension, and confusion."
As far as required spin training during a normal syllabus. I don't see much point unless the student intends to do aerobatics, instruct or possibly some other edge of envelope type flying. A lot of stall accidents occur at a height that spin recovery would be effected too late anyway, and avoidance of the situation is the best cure, rather than recovery. Practice of low speed flight and awareness of the dangers is the key, how to stop a spin from developing in the first place is the most important knowledge.

djpil 18th Aug 2022 02:05

Thanks 43Inches, agreed. Yes, there is a placard in all certified to FAR 23 and CAR 3 for intentional spins. My old Cessna 150 Handling Notes (carved from the POH by the flight school) seems to provide adequate information although the essentials rather than the detail of the Cessna Spin Document. Remember when CASA required their own AFM to their template – I didn’t keep my copy for the Cessna nor Decathlon?

I'll be lobbying CASA to write an AC focussed on spin training, more on that later when I finish my notes.

By George would know about the Chipmunk spin saga of the ‘50s – the article from the Aviation Safety Digest back then is included in the ATSB’s report of VH-UPD’s spin accident. We know the instructor was teaching the incorrect spin recovery method. Incidentally, the ATSB noted that the old CASA AFM didn’t have any instructions for spin recovery of the Chipmunk?

Yes, MagnumPI and thanks. During the lockdowns I was using Facebook to login here and my real name was displayed but it seems that Facebook has been disabled for access here.

My Super Decathlon is currently in maintenance so between that and Melbourne’s weather I have plenty of time to sit in front of my computer and display my dinosaur attributes as explained by CASA https://www.flightsafetyaustralia.com/2017/12/the-unreachables-are-they-unteachable
It will be going again soon. I also have a Cessna 152 Aerobat and a share in a Pitts S-2C.


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