Partial panel in the age of glass?

Pi1otguy

Pi1otguy

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What does partial panel look like in a glass cockpit? It's that even a sensible question?

With the old vacuum gauges we cover the AI and HI. Even experienced a real failure once. But most of the planes I've flown with even partial glass have an additional (backup?) AI somewhere.
 
You can lose all GPS, one or more ADHRS, one or more ADC's, magnetometers, and have power failures. So mimicking those modes by covering up relevant parts of the panel, or pulling CB's to those devices can mimic real life failures.

Real international flight. Military GPS jamming took out both aircraft GPS's as well as cell phone and iPad GPS's. lasted about an hour iirc.

You lose all ADS-B info including traffic, real TCAS still works if you have it.
You lose the moving map although it will go into dead reckoning mode
Lose all GPS approaches and GPS as DME
You lose GPS track outside of limited DR dead reckoning mode
Lose fuel over destination
You lose winds at altitude
You lose terrain and TAWs
You lose synthetic vision
You lose ground speed

You still have VOR's but without DME, you have to use crossing VOR radials to determine position.

Bad magnetometers take out the compass
ADC's lose speed, altitude, and in some less robust PFD's even attitude and roll
ADHRS lose attitude info

Still worth practicing flying with limited info, and if possible have redundant ADC's,. ADHR's, power sources on separate busses, Magnetometers, etc.

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The only other thing I would add is there are too many avionics platforms out there to talk specifics, but learn where the weak points in your system lie. You may have 2 GPS/ADC's/ADHRS/glass panels, but if they are all tied to the same 30 amp breaker, what happens if it trips and won't come back online? Or one buss powering all the avionics and that buss catches on fire? The redundancy may not be as deep as you think. Find those failure points and have a plan B. There are some real interesting failure modes.
 
Are you asking about real loss of capability, or the way the ACS "loss of primary instrument indicators" task is typically done for the checkride?
 
midlifeflyer said:
Are you asking about real loss of capability, or the way the ACS "loss of primary instrument indicators" task is typically done for the checkride?
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Real loses. Mainly, understanding how not to become a lawn dart if a sensor or system goes bad.
 
as a very rusty old-school pilot this seems to me to be a MAJOR pit-fall of the new stuff.

To me from the outside looking in at least, it seems like it would take many hours of study and practice to understand the various systems and failure points in any given aircraft...even between two planes operating the same primary units.... G1000 for example.

Back in my day of steam gauges pre-gps there would of course be differences but jumping between similar aircraft (such as typical trainer piston GA) wasn't such a leap.
AN HSI equipped plane isn't such a leap from one with a plane old DG
An ADF was an ADF
A VOR indicator was pretty much like any other
you had one nav/com or two
and so on....

to the original question here...other than popping a breaker where that might make sense, how does a person go about simulating all of these seemingly hidden failure modes.
yeah, the screen can go black, but it seems like there are so many other very subtle ways for trouble not resulting in a black screen
 
I’ve had:
both GPSs fail due to a bad antenna.

VOR tuning fail on a radio…the DME side still tuned properly, however.

a flux gate go bad, giving bad heading information.

half of my PFD compressed into about an 1/8” wide line.

On the other hand, I’ve never had anything that resulted in a big ❌. The system knew about the GPS failure, but since I had DME/DME/DME capability, I still had navigation, and the failure indication was “intermittent.” Admittedly my system knowledge wasn’t as good as it should have been.:rolleyes:
 
Brad W said:
as a very rusty old-school pilot this seems to me to be a MAJOR pit-fall of the new stuff.
…
to the original question here...other than popping a breaker where that might make sense, how does a person go about simulating all of these seemingly hidden failure modes.
yeah, the screen can go black, but it seems like there are so many other very subtle ways for trouble not resulting in a black screen
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There’s so many variables in panel configs that it’s tough to give you an answer.

We have dual G5s with magnetometer and a GTN650. And a second comm/nav with it’s analog lateral guidance needle. Part of the G5 STC requires we keep the airspeed indicator, VSI, and electric TC. No vacuum system means lots of Vac related failures don’t occur.

If GPS fails, the GTN still has a NAV radio and we have that second nav radio and indicator as well.
 
Brad W said:
as a very rusty old-school pilot this seems to me to be a MAJOR pit-fall of the new stuff.
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Part of it is no different than what we faced in the analog world. Pitot tube clogged is pitot tube clogged and it's still going to result in faulty airspeed indications. And a GPS failure is going to mean a loss of GPS nav whether it's a KLN 89b tied to an OBS separate from the vacuum-driven DG or a GTN xi tied to a G3X.

OTOH, vacuum failures are a thing of the past and glass comes with required redundancy. Failures are announced with big red Xes and pop-up messages. Multiple screen configurations have reversionary modes where a display failure means switching to the other, and most require airspeed, altitude, and attitude backups operating on a different system. Alternator failure pilot response in some systems is initially handled by an essential bus switch so you don't have to think (too much) about which systems to take offline. If you miss all the signals and run out of battery, many attitude instruments have internal backup batteries to get you on the ground.

Like @MauleSkinner I haven't had any big red Xes in a digital system. OTOH, I have had failures in analog cockpits. Pretty much what I would expect - not immunity from system failures but more reliability, more redundancy, and more solutions.

(BTW, I still fly both regularly)
 
midlifeflyer said:
Pitot tube clogged is pitot tube clogged and it's still going to result in faulty airspeed indications.
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And the problem still is identifying the actual failure, and what you can do to resolve it. Pitot/static malfunctions seem to confuse a lot of pilots. Mostly based on the confusing failure information given for the Cirrus chute pull out of Aspen a while back, I’d guess that it could have been flown out fairly well if the pilot could identify the point of failure and use appropriate backups without pulling the chute in the mountains in the wintertime.

midlifeflyer said:
Failures are announced with big red Xes and pop-up messages.
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As I said, I’ve never had red X’s, but I like the way the Hawker 4000 AFM phrases things…it says it will annunciated any “foreseen” malfunction. I take that to mean anything they thought of AND were able to get programmed before project funding ended.
 
And you have some sort of back up. Or multiple backups.

I sometimes fly a G1000 C-182. If the PFD fails, I can make the MFD a PFD. Plus there is a traditional AI, ASI, and Altimeter.

And I have my iPad with Fore Flight. If I add a Stratus or Sentry, I have AHRS and can fly IMC with just the iPad.

In my Mooney, I have an Aspen 1000 PFD for primary. I have a G5 backup. And I still have a Turn Coordinator, ASI, and Altimeter. Plus the GPS and iPad.
 
Pi1otguy said:
What does partial panel look like in a glass cockpit? It's that even a sensible question?

With the old vacuum gauges we cover the AI and HI. Even experienced a real failure once. But most of the planes I've flown with even partial glass have an additional (backup?) AI somewhere.
Click to expand...

My CFII has a suction cup to cover up the magenta line.
 
Instrument failure modes are going to look different, for sure. I've got dual G5s, so likely failure modes are probably going to be something like this:
  • AI unit fails. Circuit breaker gets pulled. HSI turns into AI. TC still available as backup.
  • PFD fails. Circuit breaker gets pulled. AI remains functional and can provide heading information from magnetometer. TC still available as backup. Compass available as backup for heading.
  • Magnetometer fails. GPS track information only. Compass available as backup for magnetic heading. AI and HSI function largely normally.
  • Both G5s fail for some reason (really bad day). We are flying by TC and compass.
  • Alternator failure. Normal ops with load shedding for limited time. G5s stay operational longer due to dedicated backup batteries.
  • Complete electrical failure. G5s can continue to operate in degraded mode on dedicated backup batteries. (No GPS or magnetometer aiding.)
In some of these modes, the AP will continue to function in one or more modes, depending on what data feeds are still viable. If all else fails, wing-leveling mode will work to hold a reasonable heading. Battery powered tablet, phone, and portable GPS unit continue to provide GPS nav information and XM weather.

I think (hope?) the big benefit of the G5s (or similar) is that their internal backup power lessens the potential for a complete failure in the event of an alternator or electrical anomaly. I've had various electrical and vacuum gyro failures in the past, and they are not always obvious when they start to fail. I'm hoping that a G5 either works or not, so it should (theoretically) be more obvious if an electronic gyro fails dues to its internal integrity checking.
 
Pi1otguy said:
What does partial panel look like in a glass cockpit? It's that even a sensible question?

With the old vacuum gauges we cover the AI and HI. Even experienced a real failure once. But most of the planes I've flown with even partial glass have an additional (backup?) AI somewhere.
Click to expand...

As others have said, the focus on what's being tested on a checkride, and what's being practiced for real-life situations, has changed. In fact, the Instrument ACS no longer calls it "partial panel", it uses the all-encompassing "Loss of Primary Flight Instrument Indicators". Really just rolls off the tongue, doesn't it?

When I train instrument pilots (either for a checkride, currency, IPC, whatever) on glass panels, I try to simulate reasonable ways the equipment they actually have can fail. This takes some study, both on my and their part, because in the planes I teach in (owner-flown), virtually every installation is different. Some have more redundancy than others. But even if they have a complete backup system, it STILL needs training and practice. For example, in a G1000, if a display fails, the reversionary mode allows operation from the center or right display. Seems simple, all the information is still there. But yet it still takes some practice as you now have to fly looking sideways at the display. Not something you want to do for the first time in IMC if you can avoid it.

Similarly, using an iPad with AHRS takes some practice. Not a lot, maybe, but definitely some. Now you're looking down at the yoke or off to the side or wherever you have it positioned instead of straight ahead. And the presentation is different than you're used to, etc.
 
I like the way RussR summed it up.

Training and checking will have different objectives and methodologies. As an instructor I'd certainly be drilling down pretty deeply into the given panel configuration with the client, understanding the system architecture and how failures will present themselves, practicing various profiles involving those failures, and even utilizing portables if they fell as reasonable options in the "path of degradation." This is where the training industry needs to step up and make sure that pilots are trained and ready to deal with equipment failures under IFR, well beyond what is required to pass an FAA practical test.

As a pilot examiner the ACS governs all. In the case of many modern "glass" suites (dual display) Task VII.D. "Approach with Loss of Primary Flight Instrument Indicators" will usually be flown in a basic reversionary mode. I'm aware of some examiners who may simulate loss of ADC/AHARS by covering various parts of the PFD with stickies. This gets to be a bit more of a philosophical quandary when you're dealing with aircraft which have dual ADAHRS and dual magnetometers such as the latest incarnation of the Cirrus SR-22. FAA-S-ACS-8B speaks to this in Appendix 7, which describes that Task VI.A. Nonprecision approach "... is expected to be flown with reference to backup or partial panel instrumentation or navigation display, depending on the aircraft’s instrument avionics configuration, representing the failure mode(s) most realistic for the equipment used." Getting down to brass tacks, what we see most often out there these days in the Garmin G1000. There's an aging document from Garmin called the "Guide for designated pilot examiners and certified flight instructors" which has provided guidance in this regard, but given the evolution of the product its applicability and accuracy has diminished over time. In recent years, Garmin has stated that they view a display failure as the "most likely" failure the user is likely to encounter. Based on my experience, I'd agree, and in installations which feature the aforementioned redundant ADAHRS/magnetometers I wouldn't feel comfortable suggesting a dual failure of those LRUs would be "realistic." Therefore, we dim the PFD.

Just some food for thought...
 
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Ryan F. said:
"Approach with Loss of Primary Flight Instrument Indicators" will usually be flown in a basic reversionary mode.
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I can’t speak to the Garmin stuff, but any reversionary mode in my airplane (Collins) will result in some loss of functionality, ranging from minor (no VNAV capability) to major (flight director looking at bad data). For quite a few pilots, the loss of functionality is pretty surprising.
 
Our older Cherokee has an Aspen "glass" AI/DG that does NOT require a backup AI. Gives me the creeps, so I've recently bought a Sentry with AHRS as "backup". If it proves reliable, I guess my partial panel would be to include the Sentry AI on my iPad in my scan.
 
Sundancer said:
Our older Cherokee has an Aspen "glass" AI/DG that does NOT require a backup AI. Gives me the creeps, so I've recently bought a Sentry with AHRS as "backup". If it proves reliable, I guess my partial panel would be to include the Sentry AI on my iPad in my scan.
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Just curious if this gives you the creeps more than the original steam gauges?
 
MauleSkinner said:
Just curious if this gives you the creeps more than the original steam gauges?
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Yeah, it does though, logical or not - the steam AI has moving parts that can fail. The glass AI doesn't, though it has a lot more software and electronic points of potential failure. And all software sucks. . .but point taken - if our old steam AI failed I'd be in the same boat.
 
Sundancer said:
Yeah, it does though, logical or not - the steam AI has moving parts that can fail. The glass AI doesn't, though it has a lot more software and electronic points of potential failure. And all software sucks. . .but point taken - if our old steam AI failed I'd be in the same boat.
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Bottom line, whatever your backup, spend enough training time to be comfortable with it.
 
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