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What goes through your mind when your PFD goes poooof!

On an IFR flight from LFPT to LFMA the other day, 90 minutes into the flight at FL190 it was getting time to plan the letdown. So I took my eyes away from the flight instruments and focused my attention on the iPad for a while. When I looked back up the Avidyne screen in front of me was pitch dark while the buttons around it were still illuminated. I pressed the brightness button but nothing happened. I tried to power cycle the PDF by pulling both C/Bs (one for each of R/L BUS) to no avail.

So the back lighting of the screen had probably packed up.

I took a little time to think about the situation. I was in clear VMC with good visibility and my destination reported CAVOK. No instrument approach was available anyway – just radar vectors to overhead the airport. The PFD could not have found a better time to die – well, apart from dying on the ground.

In terms of flight instruments I had the back-up horizon, speed indicator and altitude indicator. What I missed was the VSI and a heading indicator (although I had a digital read-out on the MFD map page). I also missed the HSI which was only partly backed up by the CDI on the GPS, and particularly the GS (and CRS) which precluded any ILS. The absence of VSI would make even an LNAV approach challenging as it would have to be made by sole reference to the backup AI to adjust the vertical profile. Now it was time to figure out what automation was left for me to fly the plane. With the PFD I lost the autopilot control head which pretty much precluded HDG mode, ALT pre-select and VS rate of climb/descent (the button on the A/P did does not work with the PFD on). The autopilot was flying in GPSS/ALT mode

With hindsight, since the PFD was actually operating and only the backlight had failed, I should have been able to use HDG mode even without the HDG being displayed, just by pressing the bottom right knob to select current heading, and turning to adjust the heading to either side counting the number of clicks, and I could probably have done the same with the climb/descent rate by pressing the third button from the top right and turned the selector knob to change the vertical speed by 50 fpm.

Anyway, to descend I disconnected the autopilot and flew manually using the CDI on the GPS, leveled off and selected NAV+ALT on the A/P. When given radar vectors I disconnected the autopilot and flew with reference to a ground feature and the whisky compass (until I my right seater pointed out I had the heading on the MFD).

Since I was in good VMC with view to the ground, had no problem maintaining the desired flight path and did not expect the kamikaze descents and frequent heading changes I would normally get in the Paris area, I chose not to tell ATC about my PFD failure to avoid any unnecessary drama.

Needless to say the trip back was VFR.

Knowing there is no reversionary mode on the Avidyne, I had given some thought to what I would do should I loose the PFD prior to this flight, but this experience showed I could have done better (“with hindsight”). First of all I had anticipated a complete failure of the PFD – not only a backlight failure which actually left me with a couple of additional options which I did not use. I tried to set VS using the knob on the PFD, but that did not work, probably because the PFD was still working and the A/P head active. Had I pulled both C/Bs on the PFD, I would probably have been able to use VS mode.

All in all this was a good experience and rehearsal for the next time the PFD packs up in less favourable conditions.

Last Edited by Aviathor at 25 Jan 09:38
LFPT, LFPN

You had some signs of failure. When we flew together the PFD was not so bright and I had to dim it up to see it from right seat.
I had a failure of the G1000 MFD on a DA42. Just the back lighting. In a dark nighr it’s was bearly visible.

The plane is 10 years old. Mechanic told me that was the 4 on the fleet of DA je maintain…
We expect the PFD to fail one day…

Romain

LFPT Pontoise, LFPB

Thanks for sharing.

Nice to see your thought processes throughout the incident. What is still available, what not.

Playing it through my head with my Aspen and the way my avionic is set up:

Loosing the Aspen would loose me the FD as well as altitude pre-select and the indication of Nav 2, for which there is no backup indicator.

I still would have a full CDI for Nav I (ILS) plus the full AP, as the S-Tec is operating independently from the Aspen but for HDG mode. Also GPSS would still be available. I’d also have my backup Attitude Indicator, airspeed and altitude, but no DG. Inofficially I’d also still have the Dynon D1 as a backup ADI and GPS Speed and Alt.

I’ll run that one by my folks when I do the next equipment refresher. Good one.

LSZH, Switzerland

Sounds like you did a good job. Well done. But under IFR shouldn’t you have reported that failure? Under the FARs it’s a mandatory report (98.187), not sure about European rules.

LFLP

pashab wrote:

But under IFR shouldn’t you have reported that failure?

Strictly speaking, I should. However I weighed pros and cons, and given the meteorological conditions and the lack of complexity of the remainder of the flight, I had nothing to gain by doing so. Had I been on arrival to LFPT, even on a clear day, I would have reported it because that is a really high workload arrival even with all your instruments, with a very steep descent, heading changes, several frequency changes in quick succession and with an expectation to follow instructions accurately and expeditiously. Had I not been visual and in view of the ground, I would have reported it.

LFPT, LFPN

Ok got it. Thanks for clarifying.

LFLP

What would cross my mind when the PFD goes poooof? Ours are of the type which tend to do that with a lot of smoke and maybe even some fire, so the focus will be on the cabin smoke and fire drills, pushing the PFD and the associated loss of data it was supposed to display way into the background.

If it fails silently (or rather smokelessly) then one thought would almost instantly cross my mind: “There goes another 80.000 Euros. Will the boss be patient enough to pay again this time or will he rather sell the plane? Where can I apply for another job?” Flying wise, there will be no problem. The MFD, if still working, can show the display of the PFD. Should that not work then the other pilot will get the controls and fly off his PFD. And should that not work either, there are standby instruments that are good enough for flying us home including an ILS. Autopilot and flight director will not be available in that case.

Last Edited by what_next at 25 Jan 17:00
EDDS - Stuttgart

Is there no method of reversion with the Avidyne system, to put the PFD information onto the MFD?
There certainly is in the Collins Proline 21.

Darley Moor, Gamston (UK)

Neil wrote:

Is there no method of reversion with the Avidyne system, to put the PFD information onto the MFD?

If the Avidyne is like the smaller Garmin systems (e.g. Garmin 500) which I am familiar with, then there is physically only one screen, which is divided into PFD and MFD parts. So there is really only all or nothing.

EDDS - Stuttgart

Heresy to ask it here, but if we can see the ground, shouldn’t we all be just as happy flying without reference to any instruments as we are without external visual clues?

Most of us would confess to a quick, but pointless, glance at the ASI before the final turn, but once we have our destination in sight, is there any useful information to be gleaned inside a light GA cockpit?

Glenswinton, SW Scotland, United Kingdom
29 Posts
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