0
13.3
3000 Alternator OUT
8
12.21
2700 Coolant @ 200F
-----
Original Message -----
Sent: 06/03/2009 12:35 PM
Subject: [FlyRotary] Re:
Incident No. 5119
Thanks, Bryan,
You nailed it why I do share my “most embarrassing
moments” – I want to ensure that I am the sole participant in such
incidents (don’t want to share the fame - NOT). I may be the
only one to make errors – but I strongly suspect that there is at least
one or two others out there {:>).
That’s why this list is so valuable – we all feel
comfortable sharing our knowledge and experiences - even our goofs. While
some may smugly sit back and say “well, I would have recognized the
problem and solution immediately” and my hat is off to them, my only
come-back is don’t be so certain – I’ve been certain that
specific incidents could never happen to me and found out I was wrong.
Ed
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bryan
Winberry
Sent: Wednesday, June 03, 2009 12:09 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Incident No. 5119
Ed,
Excellent report. And like Al G, excellent airmanship!
We may have to have a call in vote, ala American Idol, to determine a
“Top Gun” here.
Seriously, this account needs to be read by other pilots out there
(not just on this forum). Many good lessons learned from someone secure
enough to share their story, even if it alludes to an error. Errors that
we all make occasionally (yeah, even you Chuck Y.)
I really regret not being able to attend the Texas event.
Well done Ed,
Bryan
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Wednesday, June 03, 2009 11:17 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Incident No. 5119
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, 2nd 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 OK.
So here I am – battery is OK, alternator is OK – 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:
- Put EVERY
critical switch on your before-takeoff Check list
- Perhaps put a
guard around such critical switches to force conscious activation
- 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.
- 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.
- 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
- 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.
- 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!)
- 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?
- 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!
- 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.
- 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
Ed
Anderson
Rv-6A
N494BW Rotary Powered
Matthews,
NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
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