All electric airplane really safer?

Guest Discussion
1

Taken as a given that Vacuum pumps fail A LOT more than one encounters electrical problems, it seems to me an all-electric airplane is certainly more convenient. However, it also seems to me that in the event of any kind of electrical short/ fire / you are totally in the dark for either a few minutes while you trouble-shoot, or possibly until you get down…

In a electric/vacuum plane such as an sr-20, with an STEC rate based AP, say the 55, let’s take what statistically is a real killer of pilots, instrument failure/ partial panel / in IMC near take-off or landing. If you lose the Vacuum and the standby, your AP being rate-based is still there to keep you under control. If you have an electrical problem that necessitates a master switch off, even for a minutes, you still have the vacuum system… Seems to me like with the STEC and the dual systems you have a nice redundancy.

In the all-electric plane, you smell burning wires shortly after take-off into 500 OVC, and you properly kill the master… NOW WHAT? Four different power sources going through the same set of wires and insulation to the same electrical instruments is not true redundancy, is it?

Is there a feature about the 22 I don’t know? A standby, non-electric driven something?

And for all of you who would say, “well how often do you see that kind of failure?” I would answer probably about as often as you might need for that chute behind your heads…

I just see no safety advantage at ALL to the electric only airplane. In fact, I see a disadvantage (albeit rare) in return for added convenience.

Help

Dean

2

Taken as a given that Vacuum pumps fail A LOT more than one encounters electrical problems, it seems to me an all-electric airplane is certainly more convenient. However, it also seems to me that in the event of any kind of electrical short/ fire / you are totally in the dark for either a few minutes while you trouble-shoot, or possibly until you get down…

In a electric/vacuum plane such as an sr-20, with an STEC rate based AP, say the 55, let’s take what statistically is a real killer of pilots, instrument failure/ partial panel / in IMC near take-off or landing. If you lose the Vacuum and the standby, your AP being rate-based is still there to keep you under control. If you have an electrical problem that necessitates a master switch off, even for a minutes, you still have the vacuum system… Seems to me like with the STEC and the dual systems you have a nice redundancy.

In the all-electric plane, you smell burning wires shortly after take-off into 500 OVC, and you properly kill the master… NOW WHAT? Four different power sources going through the same set of wires and insulation to the same electrical instruments is not true redundancy, is it?

Is there a feature about the 22 I don’t know? A standby, non-electric driven something?

And for all of you who would say, “well how often do you see that kind of failure?” I would answer probably about as often as you might need for that chute behind your heads…

I just see no safety advantage at ALL to the electric only airplane. In fact, I see a disadvantage (albeit rare) in return for added convenience.

Help

Dean

Hi Dean,

About 7 years ago I owned a '62 Debonair. On an instrument flight into San Diego International in a marginal IFR weather, suddenly everything went dead. Full electrical failure. The safety fuse in the generator failed, the generator sucked the battery dry and there I was without any power. Luckily I just plunged into the clouds, so I broke off, and since I always carry an additional radio that can be plugged into #2 VOR antenna, I could still receive instructions from the tower, but they couldn’t hear me. After they put me far away from them on a heading to Japan, I broke off, climbed to 12,500 and came back home to WHP. An FAA inspector already waited for me on the ground and wanted to cite me for not landing in a nearby field, but I was the man sitting in the left chair and he accepted my reasoning. They (FAA) went through my plane with a fine toothcomb for 6 weeks, if in fact it was a design failure that all 3 items failed consecutively, but it was just one of those “one in a million crazy chance”.

So you are right, the same chance as we’ll need the CAPS.

When I get mine I’ll definitely wire up a portable radio antenna socket, have the cord and TWO sets of fresh batteries always.

Best regards,

Michael

3

Taken as a given that Vacuum pumps fail A LOT more than one encounters electrical problems, it seems to me an all-electric airplane is certainly more convenient. However, it also seems to me that in the event of any kind of electrical short/ fire / you are totally in the dark for either a few minutes while you trouble-shoot, or possibly until you get down…

In a electric/vacuum plane such as an sr-20, with an STEC rate based AP, say the 55, let’s take what statistically is a real killer of pilots, instrument failure/ partial panel / in IMC near take-off or landing. If you lose the Vacuum and the standby, your AP being rate-based is still there to keep you under control. If you have an electrical problem that necessitates a master switch off, even for a minutes, you still have the vacuum system… Seems to me like with the STEC and the dual systems you have a nice redundancy.

In the all-electric plane, you smell burning wires shortly after take-off into 500 OVC, and you properly kill the master… NOW WHAT? Four different power sources going through the same set of wires and insulation to the same electrical instruments is not true redundancy, is it?

Is there a feature about the 22 I don’t know? A standby, non-electric driven something?

And for all of you who would say, “well how often do you see that kind of failure?” I would answer probably about as often as you might need for that chute behind your heads…

I just see no safety advantage at ALL to the electric only airplane. In fact, I see a disadvantage (albeit rare) in return for added convenience.

Help

Dean

Dean:

Other than the two separate alternators and the two separate batteries, and the separate battery for the turn and bank indicator which are part of the SR22 as built, there are two items which certainly would improve safety in the event of a total electrical failure.

First, an external antenna connection for the use of a handheld nav/com should be considered essential. There appears to be ample room for an additional connector in the center console near the headset connectors.

Second, I am seriously considering installing a backup AH. BFGoodrich Avionics makes a 2 1/4" backup AH. It is described at www.bfgavionics.com under “standby instrumentation” and is the AIM520 series. If the Davtron clock/OAT/voltmeter were moved to the upper right portion of the right panel (where the suction gauge is on the SR20) this would leave a 2 1/4" open spot on the upper left of the left side of the panel. The AIM520 can be installed with a backup battery and switch similar to the turn and bank indicator. I am not sure of the specifications for the backup battery. The person I spoke with at BFGoodrich Avionics indicated that probably a gel cell battery that would be charged from the avionics bus would probably be used.

With this configuration, you would have communication and VOR navigation from the handheld and turn and bank and AH from independent electrical supplies. The AIM520 and the more expensive J.E.T. instruments are in transport catagory aircraft, installed with backup battery.

As to the possible failure points in the SR22 electrical system is concerned, perhaps someone with more detailed information regrding the two altinator and two battery system could give a detailed description of what the possibilities there are concerned. Michael’s post apparantly concerned a single generator and single battery failure. Apart from the handheld com failure, the generator and battery failure itself was apparantly pretty rare.

4

I spoke with a guy at Oshkosh this year I think from Sandel, and he said that the instruments would have a battery back up similar to the ones we use on our computer. When the master is shut off the backup automatically cuts in and the display runs for a finite amount of time. 30 - 45 minutes.
His wording was a little better than mine but it sounded pretty reassuring.

Bob

5

Taken as a given that Vacuum pumps fail A LOT more than one encounters electrical problems, it seems to me an all-electric airplane is certainly more convenient. However, it also seems to me that in the event of any kind of electrical short/ fire / you are totally in the dark for either a few minutes while you trouble-shoot, or possibly until you get down…

In a electric/vacuum plane such as an sr-20, with an STEC rate based AP, say the 55, let’s take what statistically is a real killer of pilots, instrument failure/ partial panel / in IMC near take-off or landing. If you lose the Vacuum and the standby, your AP being rate-based is still there to keep you under control. If you have an electrical problem that necessitates a master switch off, even for a minutes, you still have the vacuum system… Seems to me like with the STEC and the dual systems you have a nice redundancy.

In the all-electric plane, you smell burning wires shortly after take-off into 500 OVC, and you properly kill the master… NOW WHAT? Four different power sources going through the same set of wires and insulation to the same electrical instruments is not true redundancy, is it?

Is there a feature about the 22 I don’t know? A standby, non-electric driven something?

And for all of you who would say, “well how often do you see that kind of failure?” I would answer probably about as often as you might need for that chute behind your heads…

I just see no safety advantage at ALL to the electric only airplane. In fact, I see a disadvantage (albeit rare) in return for added convenience.

Hi Gang,

 Having had 2 total electrical failures (VFR thank God!) I am planning a second 2" AI with backup battery power for my SR22(2/2002). This is an expensive item but combined with good recurrent training, a handheld com, the 9 volt powered T+B,my 195 GPS and my BRS chute I plan to stay off the local mountain sides and off the "aftermath" pages of Flying magazine.
 However, I was wondering if anyone remembers the standyby vacuum system that ran off the differential pressure of the manifold sytstem that used to be sold to backup our old vacuum pumps. Anyone remember who made this system??? Maybe this system, which I recall kicked in automatically with the loss of the vacuum pumps, could be used to power a 2" vacuum AI giving you a totally independent sysetem should you have to kill all electrical power (as in a fire). A less inexpensive redundant system with a separate power source????? Sounds good to me! Maybe you could keep the valve closed unless you were hard IFR which would prolong the life of the system.

By the way, I’m still looking for a partner for his SR22 to be based at KSMO California.

Thanks, DAVE F.

6

Both of your plans to ADD safety features sound good. Unfortunately, they only further my feeling that I’d rather have a SR-22 with a vacuum system no matter how much it stinks to see the little back-up light come on… I just read yet another article (this one in FLYING) about pilots losing control of their wonderful machines in IFR in partial-panel situations. Of course, perhaps electrical failures in SR-22 would be better called no-panel IFR.

There’s always the mag compass and the altimeter!

Seriously, would love to hear from some Cirrus folks or others. I’m still betting there is a level of back-up I’m just plain missing.

Dean

7

Yes, anything is possible. If we bring a Doctor along just in case… What do we do if his/her fuse goes on the blink…

The portable comm is good and I will bring along my Cassiopeia (casio palm pc) Checkout controlvision.com I think we all should have one. Have a great Cirrus day.

Cheers,

Woor

8

Both of your plans to ADD safety features sound good. Unfortunately, they only further my feeling that I’d rather have a SR-22 with a vacuum system no matter how much it stinks to see the little back-up light come on… I just read yet another article (this one in FLYING) about pilots losing control of their wonderful machines in IFR in partial-panel situations. Of course, perhaps electrical failures in SR-22 would be better called no-panel IFR.

There’s always the mag compass and the altimeter!

Seriously, would love to hear from some Cirrus folks or others. I’m still betting there is a level of back-up I’m just plain missing.

Dean

As Stephen referenced earlier, there is the independently powered (9V battery) Turn Coordinator. If the TC isn’t the source of the electrical short/fire that prompted the shut-off of the master, at least you’ve got one gyro left spinning, not unlike losing vacuum in a single without a backup pump. I guess its sufficient motivation to stay proficient in partial panel work in spite of having the all-electric, multiple backup airplane.

9

Seriously, would love to hear from some Cirrus folks or others. I’m still betting there is a level of back-up I’m just plain missing.

Could well be. I’ve not seen any details on the Sr22 config, but I would have expected that to get past the FAA, there would not only have to be dual power supplies (alts and batteries) but also the electrical busses organized in a way that would eliminate single points of failure. I would also hope that there is a way of quickly shutting off all electrical power except flight instruments (to cater for the smoke in the cockpit scenario).

Personally I think vacuum pumps are like NDBs - they were ok in their day, but would never get certified today - any risk analysis would can them. I think it’s time to stop hanging onto the past just because it’s comfortable. My 2c worth.

PS - search the NTSB records for vacuum pump failures - plenty of fatal wrecks there. Second one I looked at was 4 fatalities in a P210R with dual vacuum pumps! 300 hits on “vacuum pump” the first page or two were all fatal. A search on “electrical failure” gave 110 hits, no fatals in the first two pages. Not a scientific survey, but supports my belief that I’d rather not have vacuum pumps.

10

… I would also hope that there is a way of quickly shutting off all electrical power except flight instruments (to cater for the smoke in the cockpit scenario).

Of course, you could pull the breakers on everything except the instruments, but that ain’t quick, given the location of the breaker panel next to the pilot’s right leg. (Aside: An instructor told me that this location is not good for dual instruction, since you can’t surprise the student with an electrical failure)

Personally I think vacuum pumps are like NDBs - they were ok in their day, but would never get certified today - any risk analysis would can them. I think it’s time to stop hanging onto the past just because it’s comfortable. My 2c worth.

Amen, brother.

PS - search the NTSB records for vacuum pump failures - plenty of fatal wrecks there. Second one I looked at was 4 fatalities in a P210R with dual vacuum pumps! 300 hits on “vacuum pump” the first page or two were all fatal. A search on “electrical failure” gave 110 hits, no fatals in the first two pages. Not a scientific survey, but supports my belief that I’d rather not have vacuum pumps.

Unfortunately, this doesn’t reassure me. It’s sort of like saying that hospitals are unsafe since so many people die there :slight_smile: I’m guessing that in most GA aircraft, an electrical failure just takes out the turn and bank, leaving the AI & DG intact. Not too serious, even in IMC. But, I’m nitpicking, since I agree with your conclusion that electric planes are safer.

11

PS - search the NTSB records for vacuum pump failures - plenty of fatal wrecks there. Second one I looked at was 4 fatalities in a P210R with dual vacuum pumps! 300 hits on “vacuum pump” the first page or two were all fatal. A search on “electrical failure” gave 110 hits, no fatals in the first two pages. Not a scientific survey, but supports my belief that I’d rather not have vacuum pumps.

Of course, the instruments that fail in the accidents you’ve mentioned are the same ones that will fail in the all-electric SR-22 in case of a serious electrical problem.

In fact those stats, to me, suggest that those electrical failures are not dangerous because there IS a vacuum system on the plane as well. In other words, two completely independent systems are better than one.

Or perhaps better to just say that the stats on vaccum/electrical failures from “regular” planes do not apply… And perhaps that is still what has me a little un-easy: My sense of a lack of true redundacy, but I’m probably just howling at the moon based on the ne time I’ve had to shut down the juice – in my RENTAL 152.

As for Woor, while i grant this may be all very remote, I doubt there will be more occasions to pull a parachute then there will be to turn the master switch off…

Dean

BTW - I picked the “disagree button” but I hardly mean it as a thumbs down. In fact, these kind of discussions are incredibly valuable to me.

12

Of course, the instruments that fail in the accidents you’ve mentioned are the same ones that will fail in the all-electric SR-22 in case of a serious electrical problem.

You’re absolutely right, but the point to me is that a) loss of gyros in the clouds kills people (even partial panel) and b) vacuum systems fail far more often than electrical systems, then safety will be improved by having two highly reliable redundant power sources, rather than combination of a highly reliable and a highly unreliable system. IOW, the chance of losing both vacuum and electrics is much greater than the chance of losing two electrical systems.

In fact those stats, to me, suggest that those electrical failures are not dangerous because there IS a vacuum system on the plane as well. In other words, two completely independent systems are better than one.

Psychologically, it is probably comforting to have two power sources that are very different in nature, but barring UFO encounters, the failure of one electrical system does not make failure of the other more likely - IOW it’s easy to confuse “independent” with “obviously different”. Anybody can see that a vacuum and electrical system are independent, but we have to trust the engineers when they tell us there are two independent electrical systems.

I think this “comfort zone” issue will generate the most opposition to Cirrus’ initiative, just as it has with the chute.

And I agree, this is a very interesting and worthwhile debate. Particularly since it will be many years before we have meaningful stats to settle the argument!

13

Of course, the instruments that fail in the accidents you’ve mentioned are the same ones that will fail in the all-electric SR-22 in case of a serious electrical problem.

You’re absolutely right, but the point to me is that a) loss of gyros in the clouds kills people (even partial panel) and b) vacuum systems fail far more often than electrical systems, then safety will be improved by having two highly reliable redundant power sources, rather than combination of a highly reliable and a highly unreliable system. IOW, the chance of losing both vacuum and electrics is much greater than the chance of losing two electrical systems.

In fact those stats, to me, suggest that those electrical failures are not dangerous because there IS a vacuum system on the plane as well. In other words, two completely independent systems are better than one.

Psychologically, it is probably comforting to have two power sources that are very different in nature, but barring UFO encounters, the failure of one electrical system does not make failure of the other more likely - IOW it’s easy to confuse “independent” with “obviously different”. Anybody can see that a vacuum and electrical system are independent, but we have to trust the engineers when they tell us there are two independent electrical systems.

I think this “comfort zone” issue will generate the most opposition to Cirrus’ initiative, just as it has with the chute.

And I agree, this is a very interesting and worthwhile debate. Particularly since it will be many years before we have meaningful stats to settle the argument!

Well said Clyde.

My opinion is that everyone should practice more. There should not be any reason that anyone of us can’t fly for two hours with Airspeed, Altimeter, Vertical Velocity, and good old Standy-by Compass. A good pilot will know where the best place to go is just in case. Some people wont fly a single engine airplane IFR because there is no dual engine. This is what makes the world go around. Can you imagine if everybody liked Cirrus, my position #85 might as well be # 38622095881. Our good old friend Wilbert did it, and his vaccum and electrical was not functioning.

Have you been to the store and have been told, I am sorry I can’t do anything … The computer is down. I am sure there will be some AD’s to add a Avionics master swt (backup) and other things to try to make it fool proof. I think the SR20 and SR22 are a great improvement in what we have been flying. As soon as we can cut the red tape and paper work shufle we will have some great inovations being put to work. Just an example: A landing light 28V. 250W with two connectors for power. It comes with two forms, a certificate and something else. These paper work had to be signed by two people. This is only what we see, can you imagine what tons of paper are behind for approval of such light (this has not even being installed yet). Just a light bulb… Now that you have the picture. What did you want installed where?

Thank you Cirrus for putting up with the Red tape and getting us this great machine that flies with back ups too…

Have a great day, sorry I got carried away…

Woor

14

Just an example: A landing light 28V. 250W with two connectors for power. It comes with two forms, a certificate and something else. These paper work had to be signed by two people. This is only what we see, can you imagine what tons of paper are behind for approval of such light (this has not even being installed yet). Just a light bulb… Now that you have the picture. What did you want installed where?

Thank you Cirrus for putting up with the Red tape and getting us this great machine that flies with back ups too…

Completely agree with this. It is truly amazing anything gets approved for anything. As for the all - electric, if a few of those instruments have there own little batteries that can give me 30 minutes then I won’t complain too much :wink:

Also agree with (and was going to start a separate post for ) the idea that people need to train, train, train. It’s amazing how many reports you read about even high-time pilots getting confused just enough to themselves killed in partial panel IMC. Was going to ask people how often they practiced this to stay sharp?

15

Taken as a given that Vacuum pumps fail A LOT more than one encounters electrical problems, it seems to me an all-electric airplane is certainly more convenient. However, it also seems to me that in the event of any kind of electrical short/ fire / you are totally in the dark for either a few minutes while you trouble-shoot, or possibly until you get down…

In a electric/vacuum plane such as an sr-20, with an STEC rate based AP, say the 55, let’s take what statistically is a real killer of pilots, instrument failure/ partial panel / in IMC near take-off or landing. If you lose the Vacuum and the standby, your AP being rate-based is still there to keep you under control. If you have an electrical problem that necessitates a master switch off, even for a minutes, you still have the vacuum system… Seems to me like with the STEC and the dual systems you have a nice redundancy.

In the all-electric plane, you smell burning wires shortly after take-off into 500 OVC, and you properly kill the master… NOW WHAT? Four different power sources going through the same set of wires and insulation to the same electrical instruments is not true redundancy, is it?

Is there a feature about the 22 I don’t know? A standby, non-electric driven something?

And for all of you who would say, “well how often do you see that kind of failure?” I would answer probably about as often as you might need for that chute behind your heads…

I just see no safety advantage at ALL to the electric only airplane. In fact, I see a disadvantage (albeit rare) in return for added convenience.

Hi Gang,

Having had 2 total electrical failures (VFR thank God!) I am planning a second 2" AI with backup battery power for my SR22(2/2002). This is an expensive item but combined with good recurrent training, a handheld com, the 9 volt powered T+B,my 195 GPS and my BRS chute I plan to stay off the local mountain sides and off the “aftermath” pages of Flying magazine.
However, I was wondering if anyone remembers the standyby vacuum system that ran off the differential pressure of the manifold sytstem that used to be sold to backup our old vacuum pumps. Anyone remember who made this system??? Maybe this system, which I recall kicked in automatically with the loss of the vacuum pumps, could be used to power a 2" vacuum AI giving you a totally independent sysetem should you have to kill all electrical power (as in a fire). A less inexpensive redundant system with a separate power source??? Sounds good to me! Maybe you could keep the valve closed unless you were hard IFR which would prolong the life of the system.

By the way, I’m still looking for a partner for his SR22 to be based at KSMO California.

Thanks, DAVE F.

Hello Dave,

I had one of those systems in my old Comanche, wish I could help you but I don’t know who makes it. I think Trade of Plane has some. By the way, with all the goodies that you are going to carry aloft, are you planning on using the suction from the right or left engine manifold of you Cirrus?

Happy holidays,

Cheers,

Woor

16

However, I was wondering if anyone remembers the standyby vacuum system that ran off the differential pressure of the manifold

I’m not sure how successful those systems are, but at least one installation features in the NTSB reports - did not deliver when needed. The problem is that at full throttle you get no differential vacuum, so it requires some careful operation by the pilot to ensure you stay up and stay upright. Not what you need when you’ve just had a total electrical failure.

17

However, I was wondering if anyone remembers the standyby vacuum system that ran off the differential pressure of the manifold sytstem that used to be sold to backup our old vacuum pumps. Anyone remember who made this system??? Maybe this system, which I recall kicked in automatically with the loss of the vacuum pumps, could be used to power a 2" vacuum AI giving you a totally independent sysetem should you have to kill all electrical power (as in a fire). A less inexpensive redundant system with a separate power source??? Sounds good to me! Maybe you could keep the valve closed unless you were hard IFR which would prolong the life of the system.

By the way, I’m still looking for a partner for his SR22 to be based at KSMO California.

Thanks, DAVE F.

The company is alive and well. Precise Flight has a web site at http://www.preciseflight.com/. The system has a warning light in the cockpit that comes on when the engine driven system falls below the minimum required and requires the pilot to pull a knob to activate the standby system. In our Cessna 182, it also requires no more than 16" to 18" of manifold pressure in order to create enough vaccuum differential to create 4.5" of vaccuum to power the gyroscopes.

Jim W.