Partial Panel in TAA aircraft

[Steve Knoblock]

Looking to get an idea of what folks have experienced during IFR practical check rides to meet the approach requirements in the ACS.

Specifically, for a C-172 with dual G5 installation, the round dial airspeed indicator, altimeter, VVI, and turn coordinator are required for the certified configuration.

The ACS says on page A16, "One 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."

In the old days, this was required because the most realistic failure was the vacuum pump, so you lost your ADI and DG. Made sense to use the turn coordinator with your pitot static stuff to get down.

But in the TAA world, a loss of both G-5's is not "realistic". Loss of electical power could be, but that won't kill the G-5 with it's backup battery (but it will kill the turn coordinator after the battery dies)

So how have the DPE's been enforcing the partial panel requirement? Switching to single G5 ops? or covering both G-5s and making the applicant go to needle/ball/airspeed?

Curious minds want to know what the rest of the world is experiencing............

 

[DGlaeser]

Our DPE’s fail the primary attitude instrument- whatever that is …
All acknowledge that there is no more ‘partial panel’ on TAA aircraft. The backup is typically a fully functional attitude instrument, which is a huge safety factor.
Only one failure is realistic. As long as the pilot knows his equipment, it is an annoyance more than a problem

 

[Steve Knoblock]

Yeah, agree. This issue came up a couple years ago when I was the Chief Test Pilot on the LM-100J (Civil C-130J) when we were certifying the plane. The FAA Stadardization Board pilots were getting Type rating checks in the airplane using the ATP PTS (sim wasn't certified yet), and the PTS has the same partial panel requirement. Since that airplane has 2 HUDs which are certified as PFRs, we had to figure out a way to meet the PTS requirement in an airplane with 2 HUDs and 4 HDD displays. End result was to stow the HUD (which automatically forces a PFD on the HDD infront of the pilot). Turns out this really is a big deal in that airplane when you pretty much only fly the plane with the HUD.

So what prompted the question is I upgraded my HAWK XP to Dual G5's with a GFC-500 (I already had an IFD-540), and now one of my students wants to do his IFR with me and I hadn't read much about what guys were having to do on their check rides.

Thanks

 

[midlifeflyer]

As others said, it's the reason that the FAA changed the nomenclature from "partial panel" to "Lost of Primary Flight Instrument Indicators." So, yeah, at most it's going to be flying using the backups. In the G1000 world, Garmin even provides a guide for CFIs and DPEs which, AFAIK, is followed by most. There's it's not even the backup instruments - just reversionary mode. I would expect far more discussion of system knowledge and failure modes on the ground than concern about in-flight operations.

 

[Lindberg]

But in the TAA world, a loss of both G-5's is not "realistic". Loss of electical power could be, but that won't kill the G-5 with it's backup battery (but it will kill the turn coordinator after the battery dies)

Really? I had a conversation last week with a pilot who lost both screens on a "fully redundant" system while in flight. It happens.

 

[MauleSkinner]

Really? I had a conversation last week with a pilot who lost both screens on a "fully redundant" system while in flight. It happens.

What caused it?

 

[MauleSkinner]

The FAA Stadardization Board pilots were getting Type rating checks in the airplane using the ATP PTS (sim wasn't certified yet), and the PTS has the same partial panel requirement.

[thread drift]
Actually there are some significant differences between the instrument and ATP requirements.

the instrument ACS says

Complete a nonprecision instrument approach without the use of the primary flight instruments

Where the ATP ACS says

One should 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.

Reversionary modes with a loss of CDU or Nav system are acceptable for the ATP, but the instrument ACS requires a Flight Instrument failure.

[/thread drift]

 

[RussR]

But in the TAA world, a loss of both G-5's is not "realistic". Loss of electical power could be, but that won't kill the G-5 with it's backup battery (but it will kill the turn coordinator after the battery dies)

An issue with the hardware/software/firmware could potentially take out both G5's at the same time. Think "Y2K bug" -type issues.

 

[midlifeflyer]

An issue with the hardware/software/firmware could potentially take out both G5's at the same time. Think "Y2K bug" -type issues.

LOL! I decided not to comment on the "they can't fail" part of the post.

 

[Lindberg]

What caused it?

Not entirely clear at this time, but seemed to be some type of malfunction with the backup network. Possibly a loose connection.

 

[Rex Kwan Do]

For my instrument checkride in a PA28-180 with dual G5 the DPE shut off the PFD with the power button and the HSI reverted to PFD and I flew the approach that way. It was a VOR and I have a CDI separate of the G5 so it wasn’t really that big of a deal.

 

[Jeff Oslick]

Part of the discussion of backups with the DPE (most likely on the ground) would be if you are using a yoke-mounted tablet, and that tablet is capable of using AHRS info from a good source (i.e. Garmin Pilot app will take AHRS info via a FlightStream link from a GTX-345 into it's synthetic vision mode).

 

[Rgbeard]

I also had a conversation with a pilot who has nearly $1mm wrapped up in his Bonanza. A good chunk is the entirely new panel, glass everything.

During an instrument departure in IMC, at the Cottonwood AZ airpot, his screens went to red "X". His iPad became the only working thing in the plane.

Lucky, he was able to maintain the climb and pop out on top less than a minute from the onset of the condition.

Phoenix was severe-clear VFR, and he flew to Deer Valley watching those Red "X" screens, and landed without incident.

 

[bflynn]

My instructor simulates a vacuum pump failure by turning both G5s off. Unlikely to happen in this aircraft, but as noted, it can happen to G5s. It can also happen in other airplanes that don’t have G5s.

 

[EdFred]

My instructor simulates a vacuum pump failure by turning both G5s off. Unlikely to happen in this aircraft, but as noted, it can happen to G5s. It can also happen in other airplanes that don’t have G5s.

Which is odd to simulate a vac pump failure that way, because the G5s don't run on vacuum pumps. Does he also simulate fuel exhaustion by turning off the G5s?

 

[bflynn]

Which is odd to simulate a vac pump failure that way, because the G5s don't run on vacuum pumps. Does he also simulate fuel exhaustion by turning off the G5s?

He is simulating vacuum pump failure for other airplanes because not everyone has a G5. My fault for not being explicit in the first place.

 

[Matthew]

My instructor simulates a vacuum pump failure by turning both G5s off. Unlikely to happen in this aircraft, but as noted, it can happen to G5s. It can also happen in other airplanes that don’t have G5s.

Same here

 

[jbrrapa]

But in the TAA world, a loss of both G-5's is not "realistic". Loss of electical power could be, but that won't kill the G-5 with it's backup battery (but it will kill the turn coordinator after the battery dies)

In my aircraft a loss of electrical power will render the G5 HSI useless, including heading information, because the magnetometer is powered by the ship's electrical system rather than the G5's battery.

 

[Jeff Oslick]

In my aircraft a loss of electrical power will render the G5 HSI useless, including heading information, because the magnetometer is powered by the ship's electrical system rather than the G5's battery.

Well, that is concerning. Is there an option to install a backup battery for the magnetometer? The current draw is surely tiny.

 

[DGlaeser]

If you lose the magnetometer, the HSI should revert to using the GPS track. It is not a heading but pretty close except in high crosswinds…
Loss of all electrical power is extremely rare. Losing an alternator is certainly a risk, but just puts you on the battery for as long as it lasts…

 

[midlifeflyer]

If you lose the magnetometer, the HSI should revert to using the GPS track. It is not a heading but pretty close except in high crosswinds…
Loss of all electrical power is extremely rare. Losing an alternator is certainly a risk, but just puts you on the battery for as long as it lasts…

Yes, the main issue with magnetometer loss is going to be when being vectored under IFR with a significant crosswind when, as you say, the G5 reverts to Track mode rather than Heading. That's a simple report to ATC under 91.183(c)

§ 91.183 IFR communications.
Unless otherwise authorized by ATC, the pilot in command of each aircraft operated under IFR in controlled airspace must ensure that a continuous watch is maintained on the appropriate frequency and must report the following as soon as possible--
***

(c) Any other information relating to the safety of flight.​

...as further explained in AIM 5-3-3.a.1.(h)

a. The following reports should be made to ATC or FSS facilities without a specific ATC request:

1. At all times.

(h) Any loss, in controlled airspace, of VOR, TACAN, ADF, low frequency navigation receiver capability, GPS anomalies while using installed IFR-certified GPS/GNSS receivers, complete or partial loss of ILS receiver capability or impairment of air/ground communications capability. Reports should include aircraft identification, equipment affected, degree to which the capability to operate under IFR in the ATC system is impaired, and the nature and extent of assistance desired from ATC.​

 

[Martin Pauly]

An issue with the hardware/software/firmware could potentially take out both G5's at the same time. Think "Y2K bug" -type issues.

Right - which is a good argument for having a backup instrument which is different from the primary instrument (as opposed to, say, one G5 being the backup for another G5). Ideally the backup instrument is from a different manufacturer than the primary instrument, and the two are connected in as few ways as necessary.

- Martin

 

[Steve Knoblock]

Wow. Some pretty good “rabbit holes” got opened up here. Bravo

A couple of clarifications from my original posts. My experience with the FAA Stan Board was using the ATP PTS before the ACS was released. Glad to see the language was updated in the ACS since the PTS still used the term “partial panel”

I get the comments about common software failures and loss of magnetometers, but I think some folks out there are overthinking it. Remember we are teaching new instrument pilots how to handle reasonably probable malfunctions safely enough to recover the airplane. No magnetometer? Use the mag compass. Common software faults are a design consideration addressed in RTCA DO-178B, and if the manufacturer can’t convince the FAA cert authorities there are sufficient safeguards in place within the operating system, other mitigations need to be in place to achieve certification. This is one of the reasons that a Dual G5 requires a a complete set of old analog gauges - turn coordinator, airspeed indicator, altimeter, and VVI.

“Reasonable” failures should have a procedure in the POH that we can teach and train to. Odd, bizarre, crazy malfunctions can always happen, but I’m not sure we are helping our students during initial training by discussing the myriad of emergencies that could happen. I’ve had dozens of strange malfunctions during my 30 years as a test pilot, and most of them were never in the flight manual nor were added. But I can tell you we changed designs or software address some of strange stuff we experienced

"…………………pilot training should never be the workaround for a poor design”

 

[Clip4]

I would expect a failure of #1 G5, a switch from HSI to AI on #2 G5, and an LNAV approach using the CDI display on the RNAV.

 

[TommyG]

Fail both G5. They have TC, AS, VSI, and Compass.

 

[MauleSkinner]

My experience with the FAA Stan Board was using the ATP PTS before the ACS was released. Glad to see the language was updated in the ACS since the PTS still used the term “partial panel”

When was that? At least by 2008 the language was

One approach should be flown with reference to backup or “fail down” instrumentation or navigation display depending on the aircraft’s avionics configuration.

And it’s not marked as a change.

 

[TCABM]

Fail both G5. They have TC, AS, VSI, and Compass.

And 2x G5s are only a primary replacement for 2 instruments.

Truly, failing both G5s and a GTN leaves a four instruments and a compass in the panel, at a minimum. If there’s a Nav2, then likely 5, one of which can get you to a non-precision approach.

Right up to the point system power is lost. Then it’s time to do as much of Aviate, Navigate, Communicate you can do after you wasted 45mins of G5 power to get on the ground.

Why make this harder than it needs to be unless you’re simply an aviation appliance operator and not a pilot.

 

[TommyG]

And 2x G5s are only a primary replacement for 2 instruments.

Truly, failing both G5s and a GTN leaves a four instruments and a compass in the panel, at a minimum. If there’s a Nav2, then likely 5, one of which can get you to a non-precision approach.

Right up to the point system power is lost. Then it’s time to do as much of Aviate, Navigate, Communicate you can do after you wasted 45mins of G5 power to get on the ground.

Why make this harder than it needs to be unless you’re simply an aviation appliance operator and not a pilot.

When it comes to training and proficiency, always make it harder then it needs to be. Me and the guys I fly with test each other all the time, fail as mush as possible under the hood. Why keep it boring and routine.

 

[TCABM]

When it comes to training and proficiency, always make it harder then it needs to be.

So are you saying fail both G5s and all the other instruments that remain? Simultaneously? That’s not realistic in my cockpit.

I’ve had a total power failure in a dual G5 equipped 172 due to an electrical fire ~10mi our from the airport. Granted, it was a VFR day, but the batteries kept the G5s going long enough for me to fly to the airport, land, and taxi to parking.

Since the 530W (and magnetometer) was lost when ship power was cut, there was neither HDG nor TRK being fed to the G5. Oh well, there was a whiskey compass and the standby instruments to get me there.

 

[EdFred]

...then I use the 740 to navigate.
Oh, that failed too?
Out comes the tablet.
Oh, that failed also?
Out comes the phone.
If that fails the CFI or DPE is going out the side door.

 

[tonycondon]

i turn off the primary screen usually. some schools still train with the g1000 ahrs/adc covers and if so i'll use that.

 

[Tantalum]

Depending on the equipment the failure modes look different. One of our club planes has a G5 stack with an old school TC on the right. The instructor simply holds a clipboard over the G5 stack.. low tech but it gets the job down.

 

[MacFlier]

On my check ride, the DPE turned off the Aspen and covered the backup vacuum-driven AI, despite me saying the plane had a backup vacuum pump...
I had to fly the RNAV on AS, TC, altimeter, VSI and compass.
His argument was: " not all planes you fly will be this nice, be prepared"

 

[EdFred]

On my check ride, the DPE turned off the Aspen and covered the backup vacuum-driven AI, despite me saying the plane had a backup vacuum pump...
I had to fly the RNAV on AS, TC, altimeter, VSI and compass.
His argument was: " not all planes you fly will be this nice, be prepared"

I would say, "I'm not going to fly planes that crappy under IFR."

 

[MauleSkinner]

I would say, "I'm not going to fly planes that crappy under IFR."

“I’m not going to issue an instrument rating that would allow you to.”

 

[bflynn]

On my check ride, the DPE turned off the Aspen and covered the backup vacuum-driven AI, despite me saying the plane had a backup vacuum pump...
I had to fly the RNAV on AS, TC, altimeter, VSI and compass.
His argument was: " not all planes you fly will be this nice, be prepared"

I look at it as a proof of expertise. If you can do that, you know what's going on with those instruments. AND, as a bonus, if you're ever down to those instruments, you have a fighting chance.

 

[MauleSkinner]

If you can do that, you know what's going on with those instruments.

And if you know what’s going on with those instruments, you can use them to resolve instrumentation discrepancies.

Look at the “I scared myself” thread, and imagine what your reaction would be if when you looked up, everything was indicating a descending turn, but the AI was wings level, on the horizon.
https://www.ecfr.gov/current/title-14/chapter-I/subchapter-G/part-135/subpart-B?toc=1

 

[YakDrvr]

I’m in the process of updating my panel to enable giving instrument training to my kids. It will consist of a Dynon HDX PFD, dual ADHRS with battery backup, Dynon remote transponder with ADS-B in/out, Dynon remote com radio, Avidyne IFD 440, Uavionics AV-30 as standby instrument (ADI, airspeed, altimeter, and compass with a backup battery) making the system fairly redundant with the exception of the PFD. There will be an additional PFD for the instructor (me) in back and both pilots will have an iPad linked to the IFD by wifi, essentially creating a full size MFD for both student and instructor. My plan for partial panel was to have the student cover the PFD and fly a non-precision approach using the standby ADI and the IFD440 with iPad MFD or a PAR/ASR, if I can find one available for training near me. Any suggestions/recommendations for this particular scenario?

Thanks

 

[Ryan F.]

Looking to get an idea of what folks have experienced during IFR practical check rides to meet the approach requirements in the ACS.

Specifically, for a C-172 with dual G5 installation, the round dial airspeed indicator, altimeter, VVI, and turn coordinator are required for the certified configuration.

The ACS says on page A16, "One 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."

In the old days, this was required because the most realistic failure was the vacuum pump, so you lost your ADI and DG. Made sense to use the turn coordinator with your pitot static stuff to get down.

But in the TAA world, a loss of both G-5's is not "realistic". Loss of electical power could be, but that won't kill the G-5 with it's backup battery (but it will kill the turn coordinator after the battery dies)

So how have the DPE's been enforcing the partial panel requirement? Switching to single G5 ops? or covering both G-5s and making the applicant go to needle/ball/airspeed?

Curious minds want to know what the rest of the world is experiencing............

Has been discussed prior here on POA... the most realistic failure mode, for me and most other DPEs from what I've gathered, is to create a reversionary mode scenario. In the case of dual G5s, one goes down, composite display on the remaining G5. Key thing to remember is the task itself. An approach must be flown in this configuration, so whatever failure mode is selected must be made with that in mind.

One size does not fit all. Other failure modes are possible and at the discretion of the evaluator. Also, I approach this task with a somewhat different perspective for CFI-IA applicants.

 

[Clip4]

Depending on the equipment the failure modes look different. One of our club planes has a G5 stack with an old school TC on the right. The instructor simply holds a clipboard over the G5 stack.. low tech but it gets the job down.

You might want to explain the brightness feature to this CFI.