Why we practice degraged mode

dmccormack

Touchdown! Greaser!
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Dan Mc
I learned the hard way recently why we train in degraded modes.

Was going to fly right seat with an IR friend/student down to NC and I was going to fly it back. Well equipped Single with thorough annual completed a few weeks ago.

Arrived early, ceilings lowering quickly as lines of widely spread thunderstorms crawled through the area. We had XM and Stormscope on board, so we'd have updated info, even though I did a thorough weather brief, and figured we'd be in front of the line as long as we were airborne by 0600.

Preflight, load up, call call call for Clearance, finally get through. Release time 0620 -- ok.

Startup, taxi down, runup, everything good -- hmmmmm -- XM still shows "Waiting for data." Oh well. Stormscope shows lots of activity just to the south. We'll have to ask to deviate east once we contact Center.

We launch and within a minute are in IMC, and despite winds in the 20s, it's not too rough. Still, the left seater isn't doing a very good job keeping wings level. I point to the AI, we roll through level and then head the other way. Such is learning -- I'll only interfere if bank exceeds 15 degrees or so.

I try calling Cleveland center -- nothing. Hmmm.

Lots of bright lights on the Stormscope. We need to deviate soon. The closest strike is within 25 miles.

Try again. We're at 3500, were cleared to 5k, but should have contact by now. Hmmm...

"Let's try Pitt approach..."

Nothing.

Clarksburg Approach? Nothing.

I reach for the landing lights, switch them on then off. Ammeter needle goes back to center slowly.

Hmm....

We're in a 30 degree bank.

"Let's turn on the A/P while I figure out this comm problem..."

"OK..." Relief. Wings level.

Fiddle with radios, try different frequencies -- nothing. Not a peep. Very strange.

I look at the AI -- 30 degree bank!!

What??!

I switch off the A/P, grab the yoke, try to figure out why the A/P is freaking out, don't correct the bank, then hear the Voice in My Head -- "FLY THE AIRPLANE!"

Oh yeah... wings level, descent arrested, now where are we?

I switch off the transponder, secondary comms, all lights. Panel 430 is still working, so is handheld. "Set up Direct Connellsville in the handheld." My now co-pilot complies.

I dial in the Localizer 5 Approach into KVVS. We have no radio reception, but the overlay will provide enough guidance to get us down under this cloud. Terrain nearby reaches 3000 -- I'm at 3500. I climbed to 4000, then fly direct to the IAF.

The little airplane shows up on the magenta line. We're on battery power only and the handheld has the same approach setup. I do the full procedure turn, descending to the approach altitude, We're established, but not on any needle -- no signal.

All we have is the GPS "guidance."

So be it.

We break out at 2100 MSL -- a few hundred feet above Minimums. Thank you Lord for sight.

I fly a left downwind, "You want to land it?" "No, you take it."

I land a bit fast and long but smoothly in the gusty 20+ knot wind. I let him taxi back because I had enough.

once stopped, I hopped out and called ATC to cancel.

"Yeah, we were wondering what happened..."

Lessons learned?


  • Make sure you can hear some transmissions before taking off into IMC. Sure, we were on a quiet little field early in the morning, but other ATIS would have been broadcast at that time (even if ours was OTS).
  • The A/P cannot be relied on to reduce pilot load when there are system problems.
  • A handheld GPS device with independent battery and approaches is a lifesaver.
  • Practice emergencies. They don't happen when you expect them, and are more likely when you don't expect it.
  • The time to panic is after you're on the ground, pushing the airplane back in.
  • This stuff is for keeps.
 
Wow!

Isn't this like the second major systems problem you've encountered in the past couple months?
 
Wow.....serious pucker factor for the left seat. Glad you took control and got on the ground. Thanks for sharing..... it's a good reminder for all of us to plan out duties (CRM) in case the crap hits the fan.

I love the Garmin 496, it has a mini six pack screen just for this type of situation. plug in the approach (Final app fix) from the list and check the plate. It also has at least an hour battery time for getting to an alternate. I just gave the avionics shop the go ahead to panel mount my unit and get the loran M1 out.
 
Good job. Those are the times that kill the less prepared very quickly. So easy to analyze later - so much harder to analyze while it's happening.
 
Good job. Those are the times that kill the less prepared very quickly. So easy to analyze later - so much harder to analyze while it's happening.

Yep. And it's amazing how much bad can happen in a very short time.

On the drive home I realized how badly this could have turned out.

I went home and slept for a couple of hours.
 
Wow.....serious pucker factor for the left seat. Glad you took control and got on the ground. Thanks for sharing..... it's a good reminder for all of us to plan out duties (CRM) in case the crap hits the fan.

Both seats -- it sounds all calm and cool now. T'was not the case.
 
Cripes Dan, I was tense just reading it.

Good lesson to share.
 
Good job. Those are the times that kill the less prepared very quickly. So easy to analyze later - so much harder to analyze while it's happening.

Yep, agreed.

It sucks when things break. It sucks worse when they break at bad times, which is usually when it'll happen if Murphy has his way.
 
Let's have a systems analysis moment, while the recollections are fresh.

Was the charging system indicating properly before takeoff? Also, you referenced ammeter; was there a voltmeter and, if so, what was it telling you?
 
The lack of a voltmeter in most GA planes is criminal...
If you have a cigarette lighter socket, then get one of the automobile voltmeters that plug into your lighter...
denny-o
 
Let's have a systems analysis moment, while the recollections are fresh.

Was the charging system indicating properly before takeoff? Also, you referenced ammeter; was there a voltmeter and, if so, what was it telling you?


Yes -- Ammeter straight up (as expected). No voltmeter.

FWIW, IA looked at it yesterday and claims "Everything checks out."

I'm thinking there's a grounding problem.
 
The lack of a voltmeter in most GA planes is criminal...
If you have a cigarette lighter socket, then get one of the automobile voltmeters that plug into your lighter...
denny-o


Agreed. I think every SEL should have a JPI or some such with full digital output of actual values.

Far easier to spot problems before they become emergencies.
 
Very nice work Dan, and thanks for sharing the story. Things sure could have gone south quickly if clear heads didn't prevail.

Like others, I had a pucker factor of "5" just reading your description!
 
Very nice work Dan, and thanks for sharing the story. Things sure could have gone south quickly if clear heads didn't prevail.

Like others, I had a pucker factor of "5" just reading your description!

Upon review I see I might show up as the hero -- sorry, I take no credit except being scared enough during IMC training to actually listen and believe those still-alive old geezers that said, "Make sure you can fly partial panel!!!"
 
Good job Dan.
When all else fails, as you remembered at the right time, and one of my old CFI's told me early in training FLY THE D*MN PLANE (we were good friends, he wasn't being rude).
 
Although instrument flight without electrons remains d0-able, it's a whole lot easier with electrons.....
 
Agreed. I think every SEL should have a JPI or some such with full digital output of actual values.

Far easier to spot problems before they become emergencies.

My KLN94 has a voltage output on one of the displays, along with also providing a warning if it stays below 11.9V for more than 15 seconds. I don't know if it works differently for 24V systems.

Before that, though, I bought a little cigarette lighter voltmeter. They sell them for cars, and it tells you the voltage. Pretty cheap, I bought one after my electrical failure. Now I check it pretty often, and also check each alternator periodically (shut down the engines one at a time).
 
Just to be sure I understand - were any of your instruments used for keeping the plane upright compromised? It appears to me that your AI and DG were ok but your TC was at risk.

How far away was VFR, and did you know where it was?

As an alternative (I'm NOT criticizing how you handled this), if the gyros were good would it have been reasonable to head for VFR rather than try and approach without electrons? Or was it really far away?
 
Just to be sure I understand - were any of your instruments used for keeping the plane upright compromised? It appears to me that your AI and DG were ok but your TC was at risk.

How far away was VFR, and did you know where it was?

As an alternative (I'm NOT criticizing how you handled this), if the gyros were good would it have been reasonable to head for VFR rather than try and approach without electrons? Or was it really far away?


Closest VFR was 150 NM (this was EARLY in the AM.. lots of fog and rain all around).

Vacuum was NOT compromised, but -- again -- during that "What's happening here?" time is when things get out of alignment.

Once I realized my first job was to fly the #$$#@ airplane, I relied on the AI and the Altimeter with the GPS as my approach guidance.

IF I had lost the primary GPS, I wuold have climbed and tried again with the handheld. Failing that, we had 6+ hours of fuel.

Still, that was not an enticing prospect with no comms and no electric in solid IMC with embedded CB all around.
 
FYI: You can setup a low voltage warning in the 396/496 handheld and use it as a poor man's voltmeter. I've mine set to just above "normal" battery voltage (~13V). If the alternator is doing its job then no alarm. If the alternator drops off-line then I get an early warning that I'm on the battery before it is too dead to do much good.
 
FYI: You can setup a low voltage warning in the 396/496 handheld and use it as a poor man's voltmeter. I've mine set to just above "normal" battery voltage (~13V). If the alternator is doing its job then no alarm. If the alternator drops off-line then I get an early warning that I'm on the battery before it is too dead to do much good.

That's a great tip! I'll try that!!
 
Interesting. It's odd that you had power to the 430 but no comms out of it.

I don't know what the current draw is for the GPS vs Comms (5 watts?)

But the mystery may be close to resolution. Apparently the belt was replaced with a 24" regular profile belt (sorta V shape).

But the small pulley on the alternator has teeth.

So the alt was putting out some power but the belt was likely slipping.

The theory will be tested tomorrow.
 
Maintenence by NAPA is deadly. There are many a/c here in which I will simply not fly.
 
Interesting. It's odd that you had power to the 430 but no comms out of it.

Tim,

The transmitter takes much more current than the GPS portion. For a 14 volt system the GPS takes 1.8 amps verses 7.8 amps for transmit. They also are on separate circuit breakers and can be powered separately. Also, if the power system is 28 volt, then the GPS will probably work down until about 10 to 11 volts, whereas the transmitter will stop probably at around 20 volts.
 
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Yes -- Ammeter straight up (as expected). No voltmeter.

FWIW, IA looked at it yesterday and claims "Everything checks out."

I'm thinking there's a grounding problem.

Dan,

We added an alternator test to our flight school aircraft check lists. We used Cessna's and they were all 28 volt systems. It was too common for the alternator to kick out after startup and not be noticed by the pilot until 20 or 30 minutes later when they couldn't receive on their Com. In these particular aircraft, the system could be reset by powering on and off both sides of the master switch and if it was a transient problem, the alternator would come back on line. The 172RG was the worst because it made it difficult to lower the gear, you had to pump them down. Often there would be enough energy in the battery to barely lower the gear and the voltage would drop so low that the alternator reset. So I would get a report that the electrical system failed but came back to life just before they landed when they lowered the gear.

A voltmeter, ideally with a warning is the best, but you still have to check it. An ammeter will work if you load up the electrical system with a landing light during the run up and verify that the needle dips and quickly comes back to the center. Since you are so dependent on the electrical system for IFR flight, you should diligently check it each time before departure. It has been my experience that many of the electrical failures are the result of a tripped alternator and if not tested and reset on the ground, you will find out that the system is dead withing 15 minutes of departure.
 
Its just after the big annual when I expect mechanical problems. My one rule is after any maintenance I fly the plane sans passengers, I stay near the airport and I pay close attention.
 
Dan,

We added an alternator test to our flight school aircraft check lists. We used Cessna's and they were all 28 volt systems. It was too common for the alternator to kick out after startup and not be noticed by the pilot until 20 or 30 minutes later when they couldn't receive on their Com. In these particular aircraft, the system could be reset by powering on and off both sides of the master switch and if it was a transient problem, the alternator would come back on line. The 172RG was the worst because it made it difficult to lower the gear, you had to pump them down. Often there would be enough energy in the battery to barely lower the gear and the voltage would drop so low that the alternator reset. So I would get a report that the electrical system failed but came back to life just before they landed when they lowered the gear.
I lost the alternator a few months back in a 172RG. It happened sometime after the run-up. I noticed the problem just as I was being handed off to departure. Recycled the alternator and was back in business.
 
Good learning moment. I wonder how you flew the app with no comms? I mean, it sounds like you couldn't declare the E (voice or xspndr) and it wasn't your destination or alternate airport.

I am supremely interested in the aftermath.
 
Good learning moment. I wonder how you flew the app with no comms? I mean, it sounds like you couldn't declare the E (voice or xspndr) and it wasn't your destination or alternate airport.

I am supremely interested in the aftermath.

Aftermath:

Landed successfully in gusty winds.

Put airplane away.

A&P/IA came out and figured out the belt was wrong (that HE put on !!!!
:mad3:)

It was slipping and would put out just enough charge plus residual battery to keep the Panel GPS (G430W) alive.

A few facts -- Standard ammeter showed no discharge/charge (straight up and down as usual).

ASOS had been OTS for a while.

It was 0530 on a Sunday morning -- not much traffic if any that time around here.

I called and received clearance from ATC via national Clc Delivery.

Airport is 1200' MSL. We rarely make contact with Cleveland Center before 2800' MSL.

Once I established that we had electric failure (remember -- ammeter is normal, some stuff is still working. It's hard enough to troubleshoot intermittent electrical problems on the ground) all we had was GPS for the approach.

No comms, no Nav signals, no nuttin'

VVS has a LOC 5 approach only. We had about 900' Ceiling. I used the GPS "Advisory" to fly the LOC 5, broke out, circled to land on 23.

How do you declare an emergency with no Comms?

You don't -- and you follow rule 1: Fly the airplane.

I did, and used "All available resources"

I called CLE Ctr once we were down and explained what happened.

A NASA ASRS form was completed once I returned home.
 
My electrical failure wasn't dissimilar. However I did have enough radio power to call up tower when I was 10 miles out and get them to clear me to land ahead of time. All worked out, still filled out my ASRS.

The ammeters that they put in most airplanes are awful to say the least. I'm thinking about upgrading to a digital one that gives a proper output.
 
7700 or 7600 ??

If you're NORDO for inadequate battery power, the transponder is not going to transmit either. XPDR requires a great deal of current to transmit.
 
"I called and received clearance from ATC via national Clc Delivery."

That was by cell phone? I want to know how to make the contact and then receive clearance while on the fly in an emergency situation.

It seems Dan was lucky because of the unique circumstance of Sunday, rural airport, unbusy sector.
 
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