Safety of the All-Electronic Cockpit

[alexpc]

A few articles from various sources recently have got me thinking about the safety implications of the trend towards fully-electronic cockpits in GA aircraft.

I've never relished the thought, even in airliners, of not actually being 'in control,' but being the human begging the computer to act on my commands. Nonetheless, I've got used to it - after all, critical systems are pretty reliable anyway, and are backed up and cross-checked with a good deal of redundancy.

In GA aircraft, though, it seems that isn't the case. Take, for example, the brand new Piper Saratoga that I flew in the other day - equipped with all the 'mod-cons' and fairly typical of a well-equipped modern aircraft. Now, I'm pretty sure this aircraft only has one alternator, and one (pretty small if I remember correctly) battery. So you're over the English channel in IMC and the alternator quits, or some other electrical problem occurs which leaves you with no master bus. You now have an airspeed indicator, attitude indicator, and... um... nothing else, with which to navigate safely to the nearest suitable airfield.
Being a Piper, you thankfully still have mechanical engine controls, unlike certain piston A1-powered aircraft with FADECs, which will simply hold the last throttle setting should the master electrical bus fail. And, oh great, you've been making too much use of that handheld GPS and the battery has 5 minutes remaining. Pilot workload? Ouch!


Is it just me, or has far too little thought gone into the development of the computerised GA cockpit?

[SNS3Guppy]

A few years ago I was on vectors IMC in a Piaggio Avanti and had an unusual electrical failure. Everything went completely dark. Nothing at all available, no lights, nothing at all. The flight controls are direct cable, but the nav, instrumentation, radios, and all other controls are electric.

By the same token I've flown with only electronic flight bags and had both fail within 30 seconds of each other...leaving no aeronautical data on board.

Paper charts just don't do that.

[AerocatS2A]

So you're over the English channel in IMC and the alternator quits, or some other electrical problem occurs which leaves you with no master bus. You now have an airspeed indicator, attitude indicator, and... um... nothing else, with which to navigate safely to the nearest suitable airfield

Not even a standby compass and an altimeter?

[421C]

So you're over the English channel in IMC and the alternator quits, or some other electrical problem occurs which leaves you with no master bus. You now have an airspeed indicator, attitude indicator, and... um... nothing else, with which to navigate safely to the nearest suitable airfield.

Is it just me, or has far too little thought gone into the development of the computerised GA cockpit?

and what more do you have to navigate with in a pre-EFIS Saratoga (or any other SEP for that matter) if the battery and alternator fail?

I would guess that thousands of glass cockpit SEPs have been flying since Cessna, Cirrus, Diamond introduced the G1000 and Avidyne. My impression is that all the usual accident causes are still there and the glass cockpit hasn't introduced any new ones. Given how often loss of control in IMC and controlled flight into terrain figure in aircraft accidents, I am sure the benefit of better attitude and situational awareness with a glass cockpit outweighs any risks.

[IO540]

Total loss of electrics in IFR conditions is a problem. I have a aircraft+battery powered yoke mounted GPS with ~ 10hrs battery life starting from when the power fails. Plus a handheld radio with an external antenna so very good range, headset adaptor and yoke attacheable PTT switch. I think most pilots carry a handheld GPS anyway so they would use that to continue to fly the filed route - the lost comms procedure. Not sure how one would fly an approach at the end though... with a handheld radio you can fly an SRA approach at least. It's not a good scenario but is easily and very cheaply addressed, by carrying certain non mandatory equipment. If flying IFR outside CAS, one would own nav to descend somwhere safe, over the sea perhaps. But a spare radio is really the key because ATC will always help out, and if you have plenty of fuel you have lots of time to play

[englishal]

A few articles from various sources recently have got me thinking about the safety implications of the trend towards fully-electronic cockpits in GA aircraft.
The mean time between failures of conventional instruments is about 800 hrs. With the G1000 it is well over 2000 hrs. At least if a G1000 fails completely, you're left an AI, for your "partial panel". I did my IR with an IR and when I went partial panel, I was only left with a TC ;) (incidentally I believe there is a TC hidden behind the PFD of the G1000 - so carry a screw driver ;)).

Does the good outweigh the bad though? A friend of mine is now dead because he flew into a mountain on an instrument approach in a Seneca with "steam driven" instruments (they never went missed at the MAP - obviously lack of situational awareness). You can bet your life (he did) that had he had a working G1000 he'd have had to have been really stupid to have hit that mountain.

So my own thoughts are that it is better to concentrate on the good points of these systems and train for the worst case scenario than dwell on the "what if"s. As IO says, you stick a handheld GPS in your bag, a hand held radio (mobile, whatever) and practice using them. I do that anyway with my steam driven aeroplane, but what i think I may add to my flight bag is a headset with mobile phone adaptor......

[IO540]

i think I may add to my flight bag is a headset with mobile phone adaptor......

You want a satellite phone (http://www.thuraya.com/content/thuraya-smartphone.html) in that case - I find GSM phones work only marginally for SMS text and you have to be below ~ 2000ft. Wouldn't like to try voice. I will be getting one of these sat phones on loan soon, to see how well they work for voice and internet based weather data.

Incidentally I think the MTBF varies a lot. The KFC225 autopilot will never make 800hrs without at least one servo burning out - the motor brushes don't last that long, and when they go the whole servo amplifier burns out. Stuff like the old Bendix/King HSI, KX155/165x radios, KLN94, etc lasts many years. The G1000 is at best unproven, with most having gone in only in the last 2-3 years.

But I agree it is the way forward. People just have to have backups.

It's a bit of a paradox that training could be vastly simplified if certain very simple backups were mandatory, but such legislation would be fiercely resisted.

[LateFinals]

Interesting thread. I am just getting to grips with the Cirrus 20 and feel that the situational awareness with the PFD and MFD certainly gives a better feeling of safety compared to the traditional instrumentation. Certainly practising and flying with failed panels needs to be kept current and any failure in IMC will always be challenging.

Having a portable GPS and hand-held radio is essential for extra safety no matter what plane on eflies.

LF

[IanSeager]

But I agree it is the way forward. People just have to have backups.


I've been lucky enough to fly quite a few 'electric' G1000/Avidyne aircraft. In all cases they had better backup instrumentation than my steam C182.

Ian

[wsmempson]

Which was the a/c whose instrumentation went blank over the North Sea, Ian?

[SNS3Guppy]

Don't be goaded into too much confidence by the "backup" in your 182 or Cirrus or other wonder-light airplane.

You may recall just recently a Quantas 747-400 that had a complete electrical failure, and it's got far more redundancy than what you've got. Never put yourself in a position you wouldn't go without the redundancy; always assume that your "backup" isn't there, and plan accordingly. It's the only prudent thing to do.

[IO540]

Unfortunately, if you are in IMC, all avionics are lost, and you truly have no backup for aircraft attitude, you will almost certainly die.

So you have to have a backup.

In a G1000 equipped plane there would be a traditional altimeter and a traditional AI.

There is no auto throttle so the power lever controls engine power directly (assuming any FADEC on a diesel engine actually works). And power+attitude=performance. There is also a manual trim, or should be.

Then you have a handheld GPS and a handheld radio in your bag, haven't you? :)

[soay]

After a complete failure of the main battery and alternator, in a G1000 equipped DA40-D, both radios and all navaids will cease to function. However, the backup AI can be powered by a stack of Duracells, for up to 20 minutes, and the ECU has a separate rechargeable battery, which will power it for a similar amount of time. Hopefully, that will get you to the nearest airport, but could be awkward if you're more than 20 minutes from the coast. In that case, though, any engine failure would not be a pleasant experience!

[IO540]

Is it really just 20 mins? The IFR lost comms rule is - fly current clearance - fly expected further clearance (rarely given in GA) - fly the filed route If you are on a 4hr flight and you lose electrics, you should not just drop out somewhere, hoping to land VFR... One should be able to fly the filed route after the failure of a *single* item. The single item could be the alternator; the battery is *guaranteed* to fail soon after that... Maybe I am missing something basic but it doesn't seem right.

[Fuji Abound]

From the POH:

If both alternators fail at the same time, reduce all electrical
equipment to a minimum. Expect battery power to last 30
minutes and land the airplane as soon as possible. Expect
engine stoppage after this period of time.

1. Avionics Master . . . . . . . . . . . . . . . . . . . . . . . OFF
2. LH/RH Alternator . . . . . . . . . . . . . . . . . . . . . . OFF
3. XPDR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STBY
4. LANDING GEAR . . . . . . . . . . . . . . . . . . . . . . down, when down and locked pull
Emergency Release
5. Stall/Pitot heat . . . . . . . . . . . . . . . . . . . . . . . . OFF
6. All lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF

I know there are some who think you carry on for as long as you like.

Personally with an engine dependant on electrical power and if the POH says land asap I would take it literally if I were you.

[IanSeager]

Which was the a/c whose instrumentation went blank over the North Sea, Ian?



That was an early Cirrus SR22, it was a long time ago and I believe that there was an SB that has dealt with the problem. The electrically powered AI would continue to work though.

Don't be goaded into too much confidence by the "backup" in your 182 or Cirrus or other wonder-light airplane.

I always expect stuff to fail. I was just saying that the backup instrumentation in any of the glass cockpit aircraft is as good as the primary in my C182. If my AI fails I'm left with my TC, if the PFD fails on a glass cockpit aeroplane then you're left with an AI.

Ian


Ian

[soay]

If both alternators fail at the same time ...
Just to be clear, I was talking about the DA40-D, which doesn't have the luxury of two alternators. Its POH can be downloaded from here (http://www.diamond-air.at/da40-tdi_afm_bas+M52087573ab0.html).

[Fuji Abound]

Soay

Sorry, I should have clarrified.

I didnt have the 40 POH to hand, but it is of course very similiar.

The condition of the backup battery to ensure maximium duration is critical.

[rjay259]

if i was on a flight planned route and the "alternator" failed if i saw some where to land safetly I would, I would then take out the said mobile/Sat phone and call NATS or the local ATS and cancel the flight plan.

When life property or posessions are in jepordy the manual can go to the wall.

259

[englishal]

Is it really just 20 mins?'
I think it is a "minimum of 45 minutes"....