From: Ed Anderson <eanderson@carolina.rr.com>
Subject: [FlyRotary] Incident No. 5119
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Date: Wednesday, June 3, 2009, 11:16 AM

Certainly not trying to “TOP” Al’s door incident – by the way, good airman ship and decisions, Al!  Glad the damage was no worst that it was.

 

But several folks who were not at the Texas Round up have asked about the “Ed’s Incident”.  For those of you who were at the roundup, you will probably want to skip this repeat.

Incident No. 5119

One the way to Texas I had an incident that ended up in with me and aircraft making a 7 mile engine-out glide into Craig Field ( Selma , Alabama ).  Again – NO! It was not fault of the engine or even the subsystems.  But, the complete answer is not provided until after my litany of the conditions and symptoms – can you figure it out?

I took off on Thursday AM planning on stopping in Mississippi to join up with Charlie England and Tracy.  After spending the night there, we all three would head for Texas .  But, the weather (as you are aware) has been laying over the southeast for days with rain and more rain – but I launched into it anyway as past Atlanta , GA things were forecast to improve..

Other than dodging lines of clouds and a bit of scud running, but not much, I landed at Alexandria City to the southwest of Atlanta , GA to take on fuel.  I then climbed back in and fire it up and took off. 

I noticed that during climb-out the engine would occasionally miss and thought the fuel might have had a bit of water in it, but was not really concerned.  So I fly on for approx another 45 minutes and had just passed Selma , Alabama and old Craig Air Force base, and turned west toward Mississippi , when more symptoms began to occur.

It started to act like a case of SAG (fouled spark plugs) where the rpm will drop a bit – not dangerous - just nerve racking.  But, shortly things began to go beyond the SAG symptoms, so I though I might have an injector problem (like one sticking open or not opening at all).  Since our injectors are in pairs, I tried turning off one figuring if things got better, then that pair might have a bad injector.

So I turned off one pair and sure enough the symptoms abated a bit (more on this later) so I figured I had a bad injector in that pair.  To be certain I turned this “bad” pair back on and turn off the “good” pair expecting the symptoms to really get bad as I would now be running on only the “bad” pair – much to my surprise when I turned off the “good” pair – the symptoms also abated.  So that indicated it was not an injector problem – but what? 

About this time, I decided to turn the aircraft back around toward Craig Field and dodging clouds headed back with the engine progressively getting worst. It appeared to be a fuel problem (and while that is ultimately the subsystem affected - it was not the root cause).  The fuel pressure was ranging from zero to 80 psi, other electrical things were also misbehaving.  I check the voltmeter thinking perhaps the alternator had died – but it showed 14 volts.  So back to the fuel system.

  Finally, the engine just stops with the prop standing still - like a hood ornament, I’m at around 4500-5000 MSL at this point having lost some altitude dodging a cloud (good old GPS just kept pointing to Craig Field).  At that time I am 7 miles out from Craig Field at 4500 msl with at stopped prop, a crippled seat cushion and a dry mouth.  Yes, I know I’ve been there before, but I don’t think you ever get “use” to it.  I recalled thinking things just can’t get worst when they very shortly and suddenly - did.

I keyed the radio and made a call to Craig Field at 4 miles on the GPS (I’m starting to get good at this) but before I could get their reply, I heard a “CLANK” (without the engine running you can hear things like that)  like a relay springing open (it was) and the entire panel goes dead!!!!   No radio, no engine instruments, not even a stinking LED was lit – only the battery powered GPS.  Can you spell “total electrical failure?”  Talk about a lonely feeling – amazing how comforting having lights on and radio – you could almost convince yourself this was just a practice engine-out landing, but not when the panel goes dark. No engine gauges, no radio, nada!

Well not being one inclined to panic (but I seriously considered it for a moment {:>)), I continued toward Craig field – I mean like there were lots of other alternatives.  Well Once again I found myself in the “fortunate position” of being too high, too much altitude. So I put in 40 degs of flaps to steepen my rate of descent. But, then I decided this time that rather than do the 360 I had done on a previous Incident to lose “excessive” altitude, I would try to glide - a more or less - regular traffic pattern.

However, I neglected to remember to retract the flaps.  So I found myself on the downwind around mid-field at pattern altitude (which felt normal) until I suddenly realized that you CAN NOT maintain that pattern altitude without an engine!!! Duh!

I knew I could never make it to the far end of the runway before turning base (toward the runway), so I started my turn immediately, to make matters a bit worst - I had been paralleling the runway on the downwind leg a bit too close – must have been the comforting feeling of being close to safety.  This position naturally required a tighter turn and as I turned I saw I was likely to miss the runway and land in the grass. So I though I need to steepen this turn further (this is called COFFIN CORNER), but fortunately glanced at my airspeed indicator to see it only registering 80 MPH and my rate of descent (normally 400-500 feet per minute) up to over 1000 feet per minute. The seat cushion suddenly vanished from this universe.

  But the REAL danger in this situation, as you all know, is your airspeed gets low, you are in a steep bank which greatly raises the stall speed  - meaning at 80 mph you are close to a stall in a steep turn while your are not in straight and level.  So I immediately straighten out of the turn – the little voice saying “better to land in the grass than get their concrete runway all messed up”.  So the immediate danger of a stall was adverted, but I was still pointed toward the ground with a sink rate twice as high as normal (and I’ve manage a few hard landings even with a normal sink rate).

The hardest thing to do when you are sinking at a 1000 fpm a couple hundred feet above the ground (with your nose already pointed at the ground) is to push the stick forward steeping the dive even more.  But, I manage to do that and picked enough air speed and energy to flair to a nice touch down – not even a bump.  I’ve always been amazed at what total concentration does to improve you landing {:>).

Rolled to the end of the runway and had energy to roll off onto the taxiway.   Got out, check under the aircraft for any evidence of leaks and started pulling the aircraft toward the far –off – hangar which had an airplane parked in front of it.  A nice looking young woman comes riding a bicycle out to meet me.  Hopped off and holding out her hand said “Hi I’m Angie, looks like we’ll be spending time together” – so things are starting to look up {:>)

So pulled the aircraft in to the hangar where the mechanic came over and ask what the problem was.  Well, I looked at the volt meter and it said the battery was dead. Mechanic put on a battery charger and announced “Yep! The battery is dead”.  So we both concluded that the alternator must have failed and not being able to replenish the drain on the battery by all the electrical systems such as fuel pumps, injectors, ignition coils, etc had drained the battery. 

However, there were a few problems with the analysis of a failed alternator.  First, the low voltage warning light never came on to warn of an alternator problem, 2^nd I never notice the voltmeter showing anything other than what it should for alternator voltage – like around 14 volts.  While checking the voltage after the Mechanic had charged the battery, I noticed down below that the “essential bus” switch was in the battery rather than the alternator position, so flicked it back to the alternator position figuring I must have accidentally kicked it while getting to some stuff in the baggage compartment of my RV-6A.

It was getting late and being a bit tired not to mention stressed, I needed to get a rental car and a motel for the night.  Did that, eat dinner and went to bed after sitting down and drawing out a problem tree with the entire major elements of the electrical system.

So next morning I show up at the hangar early and meet Ben, the mechanic, the battery had received a charge of only 45 minutes the evening before, So I suggested we charged it for another hour and try to start the aircraft.  Ben suggested a real stress test of the battery and NOT charge it anymore.  Made sense, so we rolled the aircraft out of the hangar.  I hopped in, threw a half dozen switches and punched the starter button.  The engine started on the first prop blade rotation – so the battery was clearly OK. The engine is humming like a top.    So I looked over at the voltmeter expecting it to show only around 12.8 volts instead of the 14 volts a functioning alternator would produce.  Much to my and Ben’s surprise the alternator voltage read 14 volts.  We loaded the alternator by turning on the both l00 watt landing lights, all fuel pumps, the pitot heat, etc.  The alternator voltage only drops perhaps 0.4 volts clearly indicating the alternator could carry the load and was O K .

So here I am – battery is O K , alternator is O K – engine is purring normally, so clearly this was all a figment of my deteriorating brain cells.  I loaded up the aircraft and launched to do a few circuits of the airport – I did so and all was operating normally and so I radio them I was head onward to Texas .  While flying, my mind could not let go of the problem and finally the light came on. 

The essential bus switch had (for my entire 10 + years of flying) been in the alternator position.  The purpose of this switch is to isolate the battery from the alternator should the alternator fail - to prevent an alternator problem from draining the battery.  So in event of an alternator problem, you move the switch from alternator to battery.  Its call the essential bus because you only have the essential things drawing from the battery so you wont’ drain it as quickly.  The idea is to give you time (generally around 30 minutes) to find a safe place to land in case of alternator failure.

Well, at some point I had either (not paying attention) turned the switch to battery thinking I was turning the voltmeter switch to battery  - or accidentally had move the switch from alternator to battery without noticing it by kicking it, etc.  However, it was sort of protected in its position from accidental activation. It must have happened during refueling – as I got approx 45 minutes down the road on the battery after take off before quality battery time started to deteriorate.  As the battery voltage fell due to the load (and no alternator link to replenish it), electrical things (mainly computers first) started acting up until they could not longer run the engine. The injectors would not open fully, etc.  Then as the voltage level further decreased, the master relay which the battery held closed and which connected the (fully functional) alternator to the rest of the electrical system - opened up and removed ALL power from the electrical system.  So no radio, no gauges, etc.

 Oh, another little factor that may have contributed, the voltmeter has a tiny toggle switch by it marked ALT BAT1 BAT2 for checking alternator battery 1 and battery 2 (which I no longer fly with) voltages.  Down below It a couple of inches and off to the right is the essential bus normal size toggle switch – also marked ALT BAT1 BAT1.  I normally never touch it and don’t even think about it.  But I could have reached for the voltmeter toggle thinking to check my battery voltage (which I do as a regular thing) and perhaps distracted by something reach a bit further down and instead moved the essential bus switch from Alternator to Battery cause this entire event.  I know that I did not consciously do it.  So it is either accidental or absence minded activation - either way ends with the same results {:>)

Now it became clear why it didn’t matter which pair of fuel injectors I turned off – turning off either pair improved the situation because it slightly reduced the electrical load by a few amps – and the engine ran slightly better for a few moments.  The same thing had happened when turning off one of the EFI fuel pumps – but what threw me was the alternator voltage continued to be normal during this.

After I knew the cause (switch in wrong position), I decided the problem was fixed so no reason to return to NC, and I just continued on to Texas .

I know some of you may think that removing my second battery was a mistake – but, consider this, having another battery could have meant I would have been much further from a suitable airfield before they both went south.  On the other hand, it might have caused me to at least think to throw the essential bus switch to the second battery and have the Light bulb come on.  Who really knows.  But, I have in mind a simply addition to my electrical circuit that should help in the future.

I do want to state that this time when the problems started I DID switch fuel tanks – but naturally it had no effect because this time it turned out, it was not a fuel problem – not the root cause at least.

So what are the lessons learned:

1. Put EVERY critical switch on your before-takeoff Check list
2. Perhaps put a guard around such critical switches to force conscious activation
3. Don’t (hard not to) get overly focused on what you think is the problem – consider other possibilities.  I thought it was a fuel problem (I even switched fuel tanks this time) – it turned out to be electrical in its root cause.
4. While the fuel pressure was jumping all over the place and the EGT was erratic and engine surging strongly indicating a fuel problem – the ultimate cause was electrical.  Once the voltage got below a certain point the EC2 was still trying to pull the injectors open, but with the voltage so low it could not do it properly.
5. When the battery voltage dropped below a certain point, the master relay released and removed the alternator from the electrical system and the panel went dark – even though the alternator was still working
6. Immediately turn to the nearest airfield when serious problems occur - THEN work on fixing them.  I only delayed for perhaps 2-3 minutes, but that could have made a difference.
7. Watch out for Coffin Corner turn when turning base to final – airspeed really bleeds off fast with no engine pulling you along (and especially with flaps deployed!)
8. IF you change your mind about landing approach type - remember to reconfigure your aircraft for the last decision – I had left my flaps deployed when I should have remembered to retracted them.  Did that help prevent a Coffin Corner stall and spin or would it have put me closer to it?
9. You must increase airspeed over the wing to get the sufficient energy to over come a high sink rate.  Pulling back on the stick when the ground is staring you in the face is the natural reaction – but, pushing forward to lower the nose is the correct action – providing of course you have sufficient altitude!
10. Battery life – I had a two year old 680 odyssey battery which I maintain a trickle charge on whenever I’m not flying.  With two EFI fuel pumps, boost pump, injectors, coils, EC2 and radio and just having started the engine before take off – this battery lasted 55 minutes.  Well, the last 5 minutes was not quality battery time.  So in my case, 30 minutes appears to be a very realistic battery life.  In fact, had I turned off one EFI pump and the boost pump would have gained a few more miles.  But, if I had recognized the need to turn them off at that time (I normally turn them off at cruise altitude), then I would have known how to “fix” the problem.
11. I’ve decided to add a Schokkty diode between my essential bus and the alternator – so that as long as the alternator is producing sufficient voltage, then the battery will be getting some charge to replace the drain.  I’ve also decided to make that switch position a check-list item.

 So what it boils down to – if I had recognized early on that it was an electrical problem and not focused so much on the fuel system, I may have noticed the essential bus switch in the wrong position.  Force yourself to examine other possible causes (easy to say – harder to do).

NEVER, NEVER forget that flying the airplane is the first and only priority in this type of situation

NEVER, NEVER forget that saving your butt is the ultimately end-all priority.  When I decided that landing on the grass was preferable to putting a hole in their concrete – I just may have made a life-saving decision.

If anybody else wants to pick up this baton – I’m ready to hand it over – what? no volunteers? {:>)

So that’s my story and I’m sticking to it. 

Fly safe, guys!!

Ed