Landing Without Engine Power

SteveinIndy said:
I can't share specific crashes and the associated information because of the limitations placed upon me by the release required to obtain the autopsy and/pr medical reports in many states and those in place because of the institutional review board at the university where my research was originally based. One of the major problems with NTSB reports is that they tend to be very short on anything related to crash survivability or occupant protection. The reports from the local law enforcement and coroner/medical examiner tend to have much more data.

I will point out that you and I agree that the Grumman is one of the better designs. Since you asked for that specifically, I went through and pulled the few crashes in Grummans. There was data for four crashes/incidents. All four ended up inverting at one some point during the crash sequence and two of those were fatal (a total of three fatalities). Three of the four had the canopy shatter. There was only one case where the victim was ejected and that involved failures of the seat attachments which resulted in fatal head, neck, chest and abdominal injuries. The passenger self-extricated after the crash but succumbed to chest and abdominal injuries possibly due to a delay in arrival of EMS providers. In the other fatality, there was a failure of the restraints (which appeared to be due to failure to replace them when they had become worn) and the pilot impacted the instrument panel with his face. The two non-fatal crashes involved nose-overs during landing rollout in both cases. Both resulted in minor to moderate injuries. One pilot received a jaw fracture from his failure to use a shoulder restrain.

Sorry for not being more "Grumman-specific" or giving more detail in the original post. I try to avoid throwing too many statistics around unless specifically asked because it can get confusing to those who aren't as well versed as you or myself. If anyone wants more detail or have questions about other models, please feel free to PM me. Ron, if you would like to read the paper once it is ready for submission, let me know. I can always afford to have a critical set of eyes go over it.
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You only found four such fatal accidents in 40+ years in the Grummans? I think that's pretty darn good, since we're averaging about 10 accidents a year, mostly landing accidents.
 
Ron Levy said:
You can find the data at the Air Safety Foundation or in FAA reports.
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You made the claim, the onus is on you to prove it, not on the reader to go on a scavenger hunt.
 
I haven't read the official "Burden of Proof" document for this board. Can you direct me to it?

dmspilot said:
You made the claim, the onus is on you to prove it, not on the reader to go on a scavenger hunt.
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wabower said:
I haven't read the official "Burden of Proof" document for this board. Can you direct me to it?
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The burden of proof is not an "official document for this board" but a requirement to make a successful argument.
 
Ron Levy said:
If the Inspector wanted you to cut power at the 180 point and land without touching power again, he was testing you on the Emergency Approach and Landing Task, not the Normal Approach and Landing task.
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For all three landings? I doubt it.
 
Tom-D said:
For all three landings? I doubt it.
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If that Inspector demanded 180 power-off approaches on all landings on your 709 ride, then your examiner was writing his own rules, either giving you three chances to get it right or not testing to the PTS criteria.
 
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At your airport those landings might be possible. At many others with higher traffic counts you wouldn't get three such approaches in an entire afternoon, let alone three in a row. So if you want to fly paper-clip patterns in the boonies, knock yourself out. If you come to town, it ain't happening.

Tom-D said:
For all three landings? I doubt it.
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dmspilot said:
The burden of proof is not an "official document for this board" but a requirement to make a successful argument.
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The data going back far enough are not available on line, and I don't have the printed data in my office. It would take a lot of work for me to obtain and post the source data, and I'm not willing to spend the time on that just to convince you that the FAA's position is statistically justified. If you really feel that my not putting that data before you is sufficient for you to justify flying contrary to the FAA's written recommendations, so be it.
 
Ron Levy said:
The data going back far enough are not available on line, and I don't have the printed data in my office.
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Bummer.

Ron Levy said:
I'm not willing to spend the time on that just to convince you
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Well, I'm pretty sure you realize I'm not the only one reading the thread, and I think you are likely to use this argument again in the future, and if your goal is not to "convince" people that your argument is correct, then why bother making it in the first place?
 
dmspilot said:
Well, I'm pretty sure you realize I'm not the only one reading the thread, and I think you are likely to use this argument again in the future, and if your goal is not to "convince" people that your argument is correct, then why bother making it in the first place?
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Because it's true, even if I don't have the data handy in a place/form to provide for the doubters. And the FAA's own position as documented in publications and the PTS should be proof enough that they are convinced on this matter. So, if you want to go on your own unsubstatiated gut feeling rather than what the FAA espouses with no basis on which to argue your point other than my lack of postable data, I can't help you. But if you're willing to accept that the FAA's prime directive is to promote safe flying, then after you've read the documents to which I posted links, as well as anything else you can find on the internet on the subject, I think you'll be convinced that the FAA is on the right track on this issue.
 
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Ron Levy said:
Because it's true, even if I don't have the data handy in a place/form to provide for the doubters.
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Even if the approach stall/spin accidents are truly "way" down as you claim, correlation does not imply causation.

Ron Levy said:
So, if you want to go on your own unsubstatiated gut feeling rather than what the FAA espouses with no basis on which to argue your point other than my lack of postable data
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I'm not making a point except that statistics an aviation are often unreliable and improperly used.
 
dmspilot said:
Even if the approach stall/spin accidents are truly "way" down as you claim, correlation does not imply causation.



I'm not making a point except that statistics an aviation are often unreliable and improperly used.
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I'll not argue either point, but I will say that whether you believe the numbers or not, the FAA, the aviation safety community, aviation academia, and the flight training industry all agree that safety is enhanced when the stabilized VFR approach is used as the normal approach to landing procedure.
 
Ron Levy said:
the FAA, the aviation safety community, aviation academia, and the flight training industry all agree that safety is enhanced when the stabilized VFR approach is used as the normal approach to landing procedure.
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I believe that over the last 40 years you have quoted, safety has been enhanced in many ways, So why should you and the other CFIs take all the credit?

We have better charts, approaches, maintenance procedures, better parts, and much better ATC services thru better radar facilities, much better weather services, and last but far from least, much better monitoring of pilot training thru bi-annual flight reviews.
 
Who's taking credit? The FAA mandated the changes and most instructors complied. The hard-cores who insist on paper-clip approaches are still out there barking at the moon, but their methodology won't stand the test of real-world operations at high-traffic airports.

Tom-D said:
I believe that over the last 40 years you have quoted, safety has been enhanced in many ways, So why should you and the other CFIs take all the credit?

We have better charts, approaches, maintenance procedures, better parts, and much better ATC services thru better radar facilities, much better weather services, and last but far from least, much better monitoring of pilot training thru bi-annual flight reviews.
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You'd probably know as much about that as anybody at this point. Was your last approach in the -24 a hairpin?

Tom-D said:
Is that the only place the accidents happen?
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wabower said:
You'd probably know as much about that as anybody at this point. Was your last approach in the -24 a hairpin?
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The improvements on brakes alone are a pretty good example.

OBTW it wasn't an accident. (isn't that where we were?)

Lots of thing influence the accident rate, the method of the approach is only one, I'd think a minor one.
 
bbchien said:
DA42 twinstar.
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which method of emergency power do they use?
Alternator and hyd. pump each engine or a RAT, or maybe a no feather option on both engines.??
 
Tom-D said:
which method of emergency power do they use?
Alternator and hyd. pump each engine or a RAT, or maybe a no feather option on both engines.??
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The DA42 doesn't require electrical power to fly, it just needs it to keep the engines running. If you lose electric power you lose both engines but it will still glide just fine.
 
You only found four such fatal accidents in 40+ years in the Grummans? I think that's pretty darn good, since we're averaging about 10 accidents a year, mostly landing accidents.
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I think you misunderstood that. I only have complete data (enough to assess in a meaningful way) 4 fatal crashes spanning about 15 years. There are other crashes but the data was either incomplete (reports "filed and lost", no autopsy conducted due to family objections, lack of data on the crash sequence which makes it very difficult to interpret the mechanics of the crash, etc). They are quite reliable and have been used previously- by Hugh de Haven, one of the pioneers in the field I work in- as an example that is better than the average design.
 
RotorAndWing said:
Permanent Magnet Alternators. Most FADEC aircraft use these to supply electric power to the computer. If aircraft electric power lost the PMA's keep the engine running.

I can't imagine an aircraft certified without them.
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While that makes sense AFaIK loss of electrical power causes both props to feather, at least that's what happened on one after the pilot departed with a dead battery experienced when the gear was raised.

http://www.flightglobal.com/news/articles/accident-ignites-da42-engine-row-213371/
 
gismo said:
The DA42 doesn't require electrical power to fly, it just needs it to keep the engines running. If you lose electric power you lose both engines but it will still glide just fine.
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Not exactly what I'd call flying safely. which is what the question asked.

It you get down in one piece, then we'll call it landing safely.
 
SteveinIndy said:
I think you misunderstood that. I only have complete data (enough to assess in a meaningful way) 4 fatal crashes spanning about 15 years. There are other crashes but the data was either incomplete (reports "filed and lost", no autopsy conducted due to family objections, lack of data on the crash sequence which makes it very difficult to interpret the mechanics of the crash, etc). They are quite reliable and have been used previously- by Hugh de Haven, one of the pioneers in the field I work in- as an example that is better than the average design.
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I think you'll need to do a lot better on your research before presenting this to your dissertation committee with the conclusions you presented in your post.
 
Ron Levy said:
I think you'll need to do a lot better on your research before presenting this to your dissertation committee with the conclusions you presented in your post.
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I will keep that in mind. You have to remember that I have a lot more data and have done a lot more analysis than what has been revealed here because of the requested focus on Grummans which are a relatively uncommon aircraft (compared to Cessnas, Cirrus and Pipers for example). Then again, a lot of the government studies of crash survivability have involved far fewer cases than I am reviewing. One of the major ones involved something like sixteen crashes.

Of course, I am also probably another four or five years from my doctorate at a minimum. As I said before (I think I said it before...), you're welcome to look over the facial trauma paper once it is done in a couple of months if you would like. I am always open to constructive criticism.

That said, do you (or anyone else) have any additional suggestions as to things to look at?
 
thezoolityre said:
I was talking about a PA28R-201 or Piper Arrow, that one doesn't like to stay up there, it might be just the one I fly specifically, but I don't think so...
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If you keep the gear up, they glide pretty well. Drop the gear, and they're more draggy than a fixed-gear PA28.
 
Tony_Scarpelli said:
They are talking mostly about static gear and static pitch props.

On one hand your R is heavier than the Cherokee's but then it has complex prop to windmill and landing gear to keep up till you make the runway.

I am thinking my Comanche has a 20x 1 glide ratio.
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I doubt it's that good - Probably closer to 15:1, maybe even less.

Constant speed prop can be better (coarse pitch) or worse (full foward) than a fixed-pitch prop.

Complex airplanes have a lot of options for changing your glide path with the engine out. The landing gear is obviously the biggest speed brake, but it's really only got two options. The prop can be used as a variable speed brake, and the flaps. Your average Cherokee/172 type bird really only has the flaps to act as a speed brake. Thus, if I'm going to have an engine failure, I hope it's in a complex airplane. (In daytime VMC, too.)
 
gismo said:
While that makes sense AFaIK loss of electrical power causes both props to feather, at least that's what happened on one after the pilot departed with a dead battery experienced when the gear was raised.

http://www.flightglobal.com/news/articles/accident-ignites-da42-engine-row-213371/
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The DA42's electrical system was supposed to be sufficient to power the ECU's, but Thielert stated that their ECU's should be able to withstand transient drops of up to 50ms, while in the accident the ECU's reset after only 1.7 ms. The article discusses this.

AD 2007-23-14 addressed this with the addition of backup power to the ECU's on the Thielert-equipped DA42's. The backup power is good for 30 minutes, which matches the length of time that the backup instrument power is good for after the rest of the aircraft's electrical system fails.

I'd be interested in knowing how many DA42's still have those engines. Diamond later came out with a Lycoming IO-360 powered variant as well as the Austro-powered DA42NG, and I think retrofits were available to either variety from the Thielert-powered ones after Thielert went bankrupt. However, I think Thielert is back in business and some operators have decided to stick with their engines, at least for now. (Both retrofits were quite expensive.)
 
flyingcheesehead said:
I doubt it's that good - Probably closer to 15:1, maybe even less.

Constant speed prop can be better (coarse pitch) or worse (full foward) than a fixed-pitch prop.

Complex airplanes have a lot of options for changing your glide path with the engine out. The landing gear is obviously the biggest speed brake, but it's really only got two options. The prop can be used as a variable speed brake, and the flaps. Your average Cherokee/172 type bird really only has the flaps to act as a speed brake. Thus, if I'm going to have an engine failure, I hope it's in a complex airplane. (In daytime VMC, too.)
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And in my case over I-20.
 
flyingcheesehead said:
Um... Since when is it faster to stop your car in neutral? :dunno:
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On snow and ice, if you are driving an automatic been like that forever. In gear there is power to the wheels, in neutral there is not. If you come to a slippery, ice area and you want to stop you need to apply the brakes and not skid. That means applying the brakes gently. Putting the vehicle in neutral take that power away from the wheels, and you will stop in a shorter distance.

They taught that in drivers ed 45 years ago, and they teach it here in the STOP classes.
 
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flyingcheesehead said:
Um... Since when is it faster to stop your car in neutral? :dunno:
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Without antilock brakes there's some truth to the notion that you can stop a car (with automatic transmission) more quickly in neutral, especially a FWD car. Below 10-15 mph many FWD cars will lock the rear wheels long before the fronts are at max threshold braking. Above that speed a RWD car will tend to lock the rear wheels before the fronts if the brake balance is 50/50 (most "modern" pre-ABS cars bias the brakes to the front about 60/40 and some had a valve tied to the rear suspension that adjusted the bias according to the weight on the rear axle).

But with the current crop of 4 wheel independent ABS the engine drag or driving force should be pretty much irrelevant.
 
SOP in my 4 years in Alaska was to slide an automatic into neutral when braking. I have seen people at stoplights fully stopped with their rear wheels spinning. Front disc brakes do most of the stopping while rear drums do very little which is why neutral is a good position. This is good for front wheel, all wheel and rear wheel drive cars, but definitely for the rear wheel variety.
 
Geico266 said:
On snow and ice, if you are driving an automatic
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gismo said:
Without antilock brakes there's some truth to the notion that you can stop a car (with automatic transmission)
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I guess that's the difference. I've never owned an automatic. :D

But with the current crop of 4 wheel independent ABS the engine drag or driving force should be pretty much irrelevant.
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Good to know. When I get married I'll own half an automatic Jeep. :)
 
Geico266 said:
On snow and ice, if you are driving an automatic been like that forever. In gear there is power to the wheels, in neutral there is not. If you come to a slippery, ice area and you want to stop you need to apply the brakes and not skid. That means applying the brakes gently. Putting the vehicle in neutral take that power away from the wheels, and you will stop in a shorter distance.

They taught that in drivers ed 45 years ago, and they teach it here in the STOP classes.
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alternatively, just stomp on the brake pedal as hard as you can and let the engineers who spent 1000's of man*hours tuning the ABS system take care of it for you.
 
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