My first in-flight mechanical failure

[Peter R.]

Given my relative low time of 700 hours, I wanted to share the story of
my first in-flight mechanical problem, which happened today while
returning from southwest Pennsylvania to central NY.

Cruising along at 11,000 feet with the XM radio playing in my headsets
(thanks to an earlier thread here, my first flight with the new XM radio
was this flight), my scan suddenly noticed the JPI engine monitor, now
flashing an increasing turbo-inlet temperature.

A quick background: I fly a turbo-normalized Bonanza and was taught by
Tornado Alley (the manufacturers of the turbo add-on) to cruise at wide-
open throttle and 75 degrees lean of turbo-inlet temperature peak. Once
this optimum lean mixture is found, the turbo-inlet temperature will
remain relatively constant throughout the remaining cruise at that
altitude. Thus, watching this temperature continue to climb to a peak
temperature, I immediately knew something was amiss.

Not knowing what was the issue, my first order of business was to take
in all the gauges and sounds to see if the engine was suffering an
imminent failure (low oil pressure, etc.) or not. The results of this
scan would determine whether I would be landing immediately or
continuing to my home airport, some 60nm away.

Other than the high TIT, there was no indication of a problem. I then
tried re-adjusting the mixture to see if somehow it had vibrated loose.
The only way to reduce the temperature was to enrichen the mixture in
through peak to some point safely rich of peak, an action that
definitely indicated a problem.

With the mixture set rich of peak and the temperature down to a safe
number, the fuel flow jumped to 24 gallons per hour (compared to 16 per
hour at lean of peak during normal cruise). I had more than enough
fuel, so I opted to leave the mixture ROP to hold down the temperature
while I thought over my options and prepared the aircraft to land at any
nearby airport.

At this point, I was out of ideas as to what the problem was, so I began
thinking how I was going to explain this problem to the mechanic Monday
morning. That is when an idea crossed my mind.

Tornado Alley states in their white paper that in order for lean of peak
operation to properly function, the magnetos and the spark plugs must
all be in excellent working order. A problem with fouled plugs or a bad
magneto would show up as a rough running engine or high temperatures
when at lean of peak.

With this, I reached down and slowly turned the key from "Both" to
"L"eft. Nothing noticeable happened in either the engine sound or the
temperatures. Back to "Both." Slowly I turned the key from "Both" past
"L" and into "R"ight. Instantaneously, the engine QUIT! Damn, I
thought, and I quickly turned the key back to "Both," returning the
engine to life. My heart-rate just when up a little.

OK, there's the problem, a dead mag. Just about the time I discovered
this, Center called me to hand me off to my class C airport's approach
control. I acknowledged the hand-off and thought for a second on how
best to safely deal with this problem.

Although it was a severe clear VFR day, I was on an IFR flight plan.
I decided that one dead mag was not an emergency, but I didn't want
to be vectored all over while approach control sequenced airliners for
their arrival, either. So, I keyed the mike and said, "Syracuse
Approach, Bonanza 2845W, level one-one thousand, with a request."

"Bonanza 45W, altimeter 30.18, go ahead with your request," answered
Approach.

"Syracuse Approach, Bonanza 45W has a mechanical problem, it is not an
emergency yet, but I do need vectors straight to the airport for an
immediate landing and I would like to remain at altitude until I get
closer."

"Bonanza 45W, expect all that, and when you have time, could you tell me
the nature of your mechanical problem?"

Since I did have a moment, I replied, "Magneto failure. The aircraft is
equipped with two mags, but if the remaining one fails, my engine will
quit. Also, I am now unsure of how the aircraft will operate at low
power settings with the dead mag while on approach."

ATC answered, "Thank you and if there is anything you need, please
ask." Knowing what she was implying, I kept the "Declare Emergency"
call on my mind and ready to use had the engine began to run rough.

I then called the airport in sight, despite still being out about 30
miles, and ATC cleared me for a visual approach. At this time I began a
gentle descent until I knew I was close. With the field made, I dropped
gear and flaps and reduced power to 17 inches MP. Not knowing what to
expect, I was pleasantly surprised to discover that the engine continued
to deliver with no roughness.

Landing was uneventful and on roll-out, tower asked me where I was
parking on the field. I replied that I needed to park at the GA
maintenance facility, to which the controller laughed and stated that
she should have known that answer.

With the leaves beginning to change color here in central NY, I am now
hopeful that maintenance will be able to replace the mag sometime early
this week. I also now have one mechanical issue to add to my growing
experience. I am not eager for others...

--
Peter

[Jay Honeck]

> With the leaves beginning to change color here in central NY, I am now
> hopeful that maintenance will be able to replace the mag sometime early
> this week. I also now have one mechanical issue to add to my growing
> experience. I am not eager for others...

Thanks for the post, Peter.

I've often wondered how a failed magneto would manifest itself in flight.

Your post will help us all.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[G.R. Patterson III]

"Peter R." wrote:
>
> I also now have one mechanical issue to add to my growing
> experience. I am not eager for others...

Good work. A mag died on me once, and I headed home. As I set up on downwind at my
untowered field, one of the local instructors announced a simulated engine out
landing. I asked him to wait a bit, since I might have the real thing on my hands!

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[dave]

A few years ago, my IFR instructor and I were shooting approaches at an
uncontrolled field in a rented archer. After a missed approach
procedure we both heard the engine noise drop. We both looked at each
and asked "did you touch the throttle?". Neither of us had so we knew
it was probably a failed mag. We continued around and landed. We
called back to the flight school to send somebody out to get us. Nice
to have two of those mags! I'm actually glad it happened. It was a good
learning experience with an undramatic and happy ending. There was no
question in either of our minds that although we could have flown back
to the fbo at PNE, we wouldn't. Why take a chance?

Dave
68 7ECA

Peter R. wrote:
> Given my relative low time of 700 hours, I wanted to share the story of
> my first in-flight mechanical problem, which happened today while
> returning from southwest Pennsylvania to central NY.
>
> Cruising along at 11,000 feet with the XM radio playing in my headsets
> (thanks to an earlier thread here, my first flight with the new XM radio
> was this flight), my scan suddenly noticed the JPI engine monitor, now
> flashing an increasing turbo-inlet temperature.
>
> A quick background: I fly a turbo-normalized Bonanza and was taught by
> Tornado Alley (the manufacturers of the turbo add-on) to cruise at wide-
> open throttle and 75 degrees lean of turbo-inlet temperature peak. Once
> this optimum lean mixture is found, the turbo-inlet temperature will
> remain relatively constant throughout the remaining cruise at that
> altitude. Thus, watching this temperature continue to climb to a peak
> temperature, I immediately knew something was amiss.
>
> Not knowing what was the issue, my first order of business was to take
> in all the gauges and sounds to see if the engine was suffering an
> imminent failure (low oil pressure, etc.) or not. The results of this
> scan would determine whether I would be landing immediately or
> continuing to my home airport, some 60nm away.
>
> Other than the high TIT, there was no indication of a problem. I then
> tried re-adjusting the mixture to see if somehow it had vibrated loose.
> The only way to reduce the temperature was to enrichen the mixture in
> through peak to some point safely rich of peak, an action that
> definitely indicated a problem.
>
> With the mixture set rich of peak and the temperature down to a safe
> number, the fuel flow jumped to 24 gallons per hour (compared to 16 per
> hour at lean of peak during normal cruise). I had more than enough
> fuel, so I opted to leave the mixture ROP to hold down the temperature
> while I thought over my options and prepared the aircraft to land at any
> nearby airport.
>
> At this point, I was out of ideas as to what the problem was, so I began
> thinking how I was going to explain this problem to the mechanic Monday
> morning. That is when an idea crossed my mind.
>
> Tornado Alley states in their white paper that in order for lean of peak
> operation to properly function, the magnetos and the spark plugs must
> all be in excellent working order. A problem with fouled plugs or a bad
> magneto would show up as a rough running engine or high temperatures
> when at lean of peak.
>
> With this, I reached down and slowly turned the key from "Both" to
> "L"eft. Nothing noticeable happened in either the engine sound or the
> temperatures. Back to "Both." Slowly I turned the key from "Both" past
> "L" and into "R"ight. Instantaneously, the engine QUIT! Damn, I
> thought, and I quickly turned the key back to "Both," returning the
> engine to life. My heart-rate just when up a little.
>
> OK, there's the problem, a dead mag. Just about the time I discovered
> this, Center called me to hand me off to my class C airport's approach
> control. I acknowledged the hand-off and thought for a second on how
> best to safely deal with this problem.
>
> Although it was a severe clear VFR day, I was on an IFR flight plan.
> I decided that one dead mag was not an emergency, but I didn't want
> to be vectored all over while approach control sequenced airliners for
> their arrival, either. So, I keyed the mike and said, "Syracuse
> Approach, Bonanza 2845W, level one-one thousand, with a request."
>
> "Bonanza 45W, altimeter 30.18, go ahead with your request," answered
> Approach.
>
> "Syracuse Approach, Bonanza 45W has a mechanical problem, it is not an
> emergency yet, but I do need vectors straight to the airport for an
> immediate landing and I would like to remain at altitude until I get
> closer."
>
> "Bonanza 45W, expect all that, and when you have time, could you tell me
> the nature of your mechanical problem?"
>
> Since I did have a moment, I replied, "Magneto failure. The aircraft is
> equipped with two mags, but if the remaining one fails, my engine will
> quit. Also, I am now unsure of how the aircraft will operate at low
> power settings with the dead mag while on approach."
>
> ATC answered, "Thank you and if there is anything you need, please
> ask." Knowing what she was implying, I kept the "Declare Emergency"
> call on my mind and ready to use had the engine began to run rough.
>
> I then called the airport in sight, despite still being out about 30
> miles, and ATC cleared me for a visual approach. At this time I began a
> gentle descent until I knew I was close. With the field made, I dropped
> gear and flaps and reduced power to 17 inches MP. Not knowing what to
> expect, I was pleasantly surprised to discover that the engine continued
> to deliver with no roughness.
>
> Landing was uneventful and on roll-out, tower asked me where I was
> parking on the field. I replied that I needed to park at the GA
> maintenance facility, to which the controller laughed and stated that
> she should have known that answer.
>
> With the leaves beginning to change color here in central NY, I am now
> hopeful that maintenance will be able to replace the mag sometime early
> this week. I also now have one mechanical issue to add to my growing
> experience. I am not eager for others...
>

[A Lieberman]

On Sun, 26 Sep 2004 19:06:47 -0400, Peter R. wrote:

> Given my relative low time of 700 hours, I wanted to share the story of
> my first in-flight mechanical problem, which happened today while
> returning from southwest Pennsylvania to central NY.

Hi Peter,

Great post, though one thought of mine.... (coming from a person who had an
in-flight exhaust valve failure last year).

Understanding the need for trouble shooting, I personally would have done
everything you did except test the mags. (unless the emergency checklist
said to do this).

My rational for this would be why change a configuration for what appeared
to be a good running engine especially when you were able to cool the
engine temperature with mixture?

I am curious, had it been hard IFR, would you have check the mags???

I by no means do not want the above to look like I am criticizing, as I
know Monday night quarterbacking is always easier then being in the hot
seat.

The results count the most, and that you brought yourself back to terra
firma without incident shows you made all the right decisions.

Allen

[G.R. Patterson III]

Jay Honeck wrote:
>
> I've often wondered how a failed magneto would manifest itself in flight.

If you don't have an engine analyzer (as Peter did), it shows up as a sudden 50 rpm
or so drop -- just like it does when you're doing your runup.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Jay Honeck]

> If you don't have an engine analyzer (as Peter did), it shows up as a
sudden 50 rpm
> or so drop -- just like it does when you're doing your runup.

So, since I *do* have a JPI engine analyzer, it won't do that?

;-)

(Sorry, I couldn't help myself...)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Jack Allison]

Great post Peter, thanks much for sharing. Very glad to hear that you
got back on the ground ok.

--
Jack Allison
PP-ASEL, IA Student

"When once you have tasted flight, you will forever walk the Earth
with your eyes turned skyward, for there you have been, and there
you will always long to return"
- Leonardo Da Vinci

(Remove the obvious from address to reply via e-mail)

[Kevin Brown]

On 2004-09-27, dave > wrote:
> A few years ago, my IFR instructor and I were shooting approaches at an
> uncontrolled field in a rented archer. After a missed approach
> procedure we both heard the engine noise drop. We both looked at each
> and asked "did you touch the throttle?". Neither of us had so we knew
> it was probably a failed mag. We continued around and landed. We
> called back to the flight school to send somebody out to get us. Nice
> to have two of those mags! I'm actually glad it happened. It was a good
> learning experience with an undramatic and happy ending. There was no
> question in either of our minds that although we could have flown back
> to the fbo at PNE, we wouldn't. Why take a chance?

Taking off with a bad magneto is a really stupid thing to do, and has
actually killed people. See:

http://www.aopa.org/asf/epilot_acc/atl02fa137.html

in which a CFI and his student elect to takeoff despite knowing that
the plane has a malfunctioning magneto. CFIs should know better than
that.


So you made the right choice by not flying an airplane with known
mechanical problems.



--
Kevin Brown

[Ron Rosenfeld]

On Sun, 26 Sep 2004 19:06:47 -0400, Peter R. >
wrote:

>ATC answered, "Thank you and if there is anything you need, please
>ask." Knowing what she was implying, I kept the "Declare Emergency"
>call on my mind and ready to use had the engine began to run rough.

Peter,

You handled the problem well and I enjoyed reading about your thought
process. They were clear and logical, and the TAT teachings obviously
helped.

However, I think all too often we GA pilots are reluctant to declare an
emergency. And I know I would have in the situation you were in.

Although you were not in a DISTRESS situation, as defined by the AIM, you
were clearly in an URGENCY situation. And BOTH are reasons for declaring
an emergency.

I've never had to fill out any paper work, or even answer any FAA
questions, on the various times I've declared an emergency. On two
occasions, when the fire trucks were rolled, I was asked to provide my name
and the nature of the emergency -- but this was for the local emergency
team logs. But I would expect even FAA paperwork, if required, to be
fairly innocuous. I've declared in both distress and urgency situations.

There's really no downside to using the 'E' word. And it's use in your
situation would have been congruent with AIM recommendations.

I recall a USAF pilot declaring an emergency after an engine failure in a
4-engine airplane, but proceeding on to home base which was hundreds of
miles away. And then there's the apocryphal USAF story about a fighter low
on fuel in Vietnam who had to delay his landing because a B52 had declared
an engine out emergency and had to execute the "dreaded seven-engine
approach" :-).

=========================
AIM 6-1-2. Emergency Condition- Request Assistance Immediately

a. An emergency can be either a distress or *urgency* condition as
defined in the Pilot/Controller Glossary. Pilots do not hesitate to declare
an emergency when they are faced with distress conditions such as fire,
mechanical failure, or structural damage. However, some are reluctant to
report an *urgency* condition when they encounter situations which may not
be immediately perilous, but are potentially catastrophic. An aircraft is
in at least an *urgency* condition the moment the pilot becomes doubtful
about position, fuel endurance, weather, or any other condition that could
adversely affect flight safety. This is the time to ask for help, not after
the situation has developed into a distress condition.

-----------------------
PC/G: URGENCY- A condition of being concerned about safety and of requiring
timely but not immediate assistance; a potential distress condition.
========================


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Peter R.]

A Lieberman wrote:


<snip>
> My rational for this would be why change a configuration for what appeared
> to be a good running engine especially when you were able to cool the
> engine temperature with mixture?

A valid point. I had typed this wordy response, but looking back at the
incident, it was much more simple: Given the severe clear, nearby
airports, and high altitude, I believed I had many options in the event
of a complete engine failure and didn't see the risk in testing the
mags.

One only need to recall the Alaska Air accident off the coast of
California to understand that too much troubleshooting can sometimes be
fatal.

> I am curious, had it been hard IFR, would you have check the mags???

Hmmmm... I would be *much* more conservative in hard IFR. In fact, I
most likely would have declared an emergency. The key point to
understand in my actual scenario is that I had many options. In hard
IFR, I would not have had but a few.

--
Peter

[Peter R.]

Ron Rosenfeld wrote:

> Although you were not in a DISTRESS situation, as defined by the AIM, you
> were clearly in an URGENCY situation. And BOTH are reasons for declaring
> an emergency.

Perhaps. In my case, I received exactly what I needed to end the
flight: Direct to the airport and remain high with pilot discretion to
descend when I felt it was safe to do so.

Had ATC deviated from my plan or (as I replied to Alan), had it been
hard IFR, I would have declared an emergency.



--
Peter

[Peter R.]

Peter R. wrote:

> as I replied to Alan)

Sorry, Allen not Alan.

--
Peter

[Peter R.]

I wrote:

<snip>
> OK, there's the problem, a dead mag.

I just received a call from my trusted mechanic early this morning.
He discovered that a capacitor failed in-flight, which in turn grounded
the mag.

This is a bit beyond my limited knowledge of aircraft mechanics and I
cannot correctly explain what a capacitor does, but the good news is
that it is much cheaper to replace a capacitor than a mag.

--
Peter

[Marco Leon]

I'm with you on that one Peter. I didn't get the impression that you were
hesitant to declare an emergency for any other reason than you didn't really
think it was an emgergency. You received the same results (i.e. service from
ATC) and that's what counts.

Thanks for the post. I hope I'm able to act the same way if I ever encounter
a similar situation.

Regards,

Marco

"Peter R." > wrote in message
...
> Peter R. wrote:
>
> > as I replied to Alan)
>
> Sorry, Allen not Alan.
>
> --
> Peter
>
>
>
>
>

[JohnMcGrew]

In article >, Peter R.
> writes:

>Not knowing what to
>expect, I was pleasantly surprised to discover that the engine continued
>to deliver with no roughness.
>
>Landing was uneventful...

Good show. That's why they give you two of those.

Years ago, had an emergency in a SuperCub when a hydraulic valve lifter
assembly went fubar at 6000 agl. Performance was slowly deteriorating, and
streaks of oil started appearing on the windscreen. We declared an emergency
and arrived over FUL with over 3000 feet to spare. The clowns in the tower
wanted to vector us off towards Disneyland to decend so that they wouldn't have
to mess up the traffic in the pattern. Still not knowing the exact cause of
the problem and being concerned that the engine might quit at any moment, we
didn't think that flying away from a made airport was a good idea, and in no
uncertain terms declined the instruction. The traffic was cleared and after a
few tight circles we landed with no problem. We cleared the runway and shut
down.

Later we found out that the tower guys had a bet going on wether or not we had
run low on fuel. After landing, they had expected to see us sneak over to the
fuel pit. They didn't expect to see us imediately shut down off the taxiway.
When one of the ground workers came over and saw oil dripping out of the
engine, their contest was resolved.

John

[Michael]

Peter R. > wrote
> I just received a call from my trusted mechanic early this morning.
> He discovered that a capacitor failed in-flight, which in turn grounded
> the mag.
>
> This is a bit beyond my limited knowledge of aircraft mechanics and I
> cannot correctly explain what a capacitor does, but the good news is
> that it is much cheaper to replace a capacitor than a mag.

In case you care:

Most mag installations in modern (read - designed for electrical
systems and radios) aircraft have a capacitor between P-lead and
ground. This absorbs some of the electrical noise, and generally
reduces static on the radios.

These capacitors fail with depressing regularity, but they usually
fail 'open' - that is, they stop doing their job and radio noise
increases, but the mag keeps working. This is the first time I've
heard of one failing 'shorted' - but if one does fail shorted, you
ground the P-lead and it's as if you turned the mag off.

Glad that worked out for you - those things ARE cheap - should be
about $30 for the part and 30 minutes to change it.

Michael

[Peter R.]

Michael wrote:

> In case you care:

Of course I care. :) Hence the secretly placed bait, which you
thankfully took!

> Most mag installations in modern (read - designed for electrical
> systems and radios) aircraft have a capacitor between P-lead and
> ground. This absorbs some of the electrical noise, and generally
> reduces static on the radios.

Very interesting. Over the last three months I have been having mag
noise problems (pop-pop-pop on frequency) whenever I used the Garmin
G430 com radio and full power, almost exclusively when tuned to a higher
frequency (130.00 or above). This interference did not occur with the
older B/K comm radio I use as my second radio, so I would end up using
the B/K radio during cruise.

When I asked a trusted avionics shop about this, they explained that the
mag itself was causing the interference and that the Garmin circuitry
was more sensitive to the interference than the older B/K radio. Based
on your explanation, I wonder now if it was really this capacitor
showing signs of imminent failure?

> These capacitors fail with depressing regularity, but they usually
> fail 'open' - that is, they stop doing their job and radio noise
> increases, but the mag keeps working.

Good to know.

> This is the first time I've
> heard of one failing 'shorted' - but if one does fail shorted, you
> ground the P-lead and it's as if you turned the mag off.

That is almost word-for-word how my mechanic explained the mag failure.

Thank you for your explanation.

--
Peter

[Peter R.]

JohnMcGrew wrote:

> Later we found out that the tower guys had a bet going on wether or not we had
> run low on fuel.

Nice to see someone casually betting on what could be a life or death
situation. Unlike a coach betting on his own team, though, at least the
controller gave you what you needed to have a successful outcome,
regardless of the side they chose in the bet. :)

--
Peter

[Andrew Gideon]

Michael wrote:

> These capacitors fail with depressing regularity, but they usually
> fail 'open' - that is, they stop doing their job and radio noise
> increases, but the mag keeps working.

Which would yield an unexpectedly "hot" prop with the switch in the "off"
position, yes?

- Andrew

[Bob Moore]

Andrew Gideon > wrote

> Which would yield an unexpectedly "hot" prop with the switch in the
> "off" position, yes?

No!

Bob Moore

[Andrew Gideon]

Bob Moore wrote:

> Andrew Gideon > wrote
>
>> Which would yield an unexpectedly "hot" prop with the switch in the
>> "off" position, yes?
>
> No!

<Sigh>

So that would only occur if the capacitor failed "closed"?

- Andrew

[Rutger]

"G.R. Patterson III" > wrote in message >...
> Jay Honeck wrote:
> >
> > I've often wondered how a failed magneto would manifest itself in flight.
>
> If you don't have an engine analyzer (as Peter did), it shows up as a sudden 50 rpm
> or so drop -- just like it does when you're doing your runup.

With the constant speed prop in the turbo'ed Bonanza, prop knob set
for cruise at 11000MSL (instead of full forward on the ground like at
runup), could you really sense that much of an rpm drop? Or would the
change in MP be more pronounced at the sudden loss of a mag?

[G.R. Patterson III]

Jay Honeck wrote:
>
> So, since I *do* have a JPI engine analyzer, it won't do that?

Nope. There's a little section of the engine that knows you have an analyzer, and it
prevents the usual rpm drop when a mag fails. This is the same section of the engine
that causes a nearly imperceptible miss when you're about halfway across Lake
Michigan on the way to Osh.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Michelle P]

George,
If you have a Constant Speed prop you will not see the RPM drop as long
as you are within the authority of the governor.
You will see a change in Manifold pressure and eventually a slight drop
in Airspeed.
Speaking from experience.
Michelle

G.R. Patterson III wrote:

>Jay Honeck wrote:
>
>
>>I've often wondered how a failed magneto would manifest itself in flight.
>>
>>
>
>If you don't have an engine analyzer (as Peter did), it shows up as a sudden 50 rpm
>or so drop -- just like it does when you're doing your runup.
>
>George Patterson
> If a man gets into a fight 3,000 miles away from home, he *had* to have
> been looking for it.
>
>

--

Michelle P ATP-ASEL, CP-AMEL, and AMT-A&P

"Elisabeth" a Maule M-7-235B (no two are alike)

Volunteer Pilot, Angel Flight Mid-Atlantic

Volunteer Builder, Habitat for Humanity

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
>> These capacitors fail with depressing regularity, but they usually
>> fail 'open' - that is, they stop doing their job and radio noise
>> increases, but the mag keeps working.
>
> Which would yield an unexpectedly "hot" prop with the switch in the "off"
> position, yes?

To elaborate on Bob's correct reply...

A broken p-lead would result in a "hot" prop even with the ignition off.
But the capacitor, not being the normal component used to short out the mag,
would have no such effect if it failed open.

The capacitor is in the circuit in parallel with the normal path of the
current. If it fails in the closed circuit state, this provides an
alternate route for the current coming from the magneto, shorting it out and
preventing a spark from being generated. But when it fails in the open
state, there is still the normal path of the current available for shorting
out the magneto when the ignition switch is in the off position.

Make sense?

Pete

[Peter Duniho]

"Michelle P" > wrote in message
ink.net...
> If you have a Constant Speed prop you will not see the RPM drop as long as
> you are within the authority of the governor. [...]

You should perceive at least some drop. The prop governor cannot react
instantaneously, and the engine RPM will drop before the governor has time
to reduce the prop pitch and allow the RPM to come back to the set point.

Not all pilots are sensitive enough to the sounds their airplane is making,
but one who is should definitely note a momentary drop in RPM if a magneto
goes offline in an airplane with a constant speed prop.

In my airplane, I get much smaller fluctuations in power, caused by the
turbocharger's density controller "hunting" slightly during full-power
climbs in hot weather. The RPM change is barely perceptible on the gauge
(no more than 10 RPM up or down), but it's easily noticed by ear. A failed
mag would cause a much more significant change in RPM than that before the
prop governor can bring things back to the set point.

> Speaking from experience.

If you failed to notice a change in RPM when your mag failed in a
constant-speed prop-equipped airplane, maybe some music lessons will help
you be more perceptive to what your airplane is telling you. :)

Pete

[Capt.Doug]

>"Jay Honeck wrote in message > I've often wondered how a failed magneto
>would manifest itself in flight.

With some engines, you might not notice tht a magneto has failed in flight.
I was flying a C-310Q in cruise and one engine burped momentarily but
continued to run normally. While doing my run-up the next day, I discovered
what caused the burp. Nowadays, I train my charter pilots to check the mags
after landing so that if a mag has failed, maintenance has all night to fix
it.

D.

[Peter Duniho]

"Andrew Gideon" > wrote in message
online.com...
>>> Which would yield an unexpectedly "hot" prop with the switch in the
>>> "off" position, yes?
>>
>> No!
>
> <Sigh>
>
> So that would only occur if the capacitor failed "closed"?

No. If the capacitor failed closed, that would short out the magneto, and
prevent it from working. In fact, that's exactly what happened to the
original poster here. It would not result in a "hot" prop.

[Peter Duniho]

"Capt.Doug" > wrote in message
...
> With some engines, you might not notice tht a magneto has failed in
> flight.
> I was flying a C-310Q in cruise and one engine burped momentarily but
> continued to run normally. While doing my run-up the next day, I
> discovered
> what caused the burp. Nowadays, I train my charter pilots to check the
> mags
> after landing so that if a mag has failed, maintenance has all night to
> fix
> it.

In addition to the "burp", you should also note increased fuel flow or
higher EGT/TIT temperatures (depending on whether you readjust the mixture
to compensate for the less-complete combustion). Nothing wrong with
checking the mags after landing, of course, but I've never heard of a mag
failing in flight where there was NO actual indication that it had failed.

[G.R. Patterson III]

Michelle P wrote:
>
> If you have a Constant Speed prop you will not see the RPM drop as long
> as you are within the authority of the governor.

Well, when I bought my Maule, I couldn't scrape up the extra $15k for the version
with the CS prop. :-)

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Gerald Sylvester]

Marco Leon wrote:
> I'm with you on that one Peter. I didn't get the impression that you were
> hesitant to declare an emergency for any other reason than you didn't really
> think it was an emgergency.

having failed magnetos is definitely an emergency. Can the other fail
too? Sure. The first died so it would be a good assumption to say the
2nd are stressed an equal amount and possibly now even more. Is a dead
stick landing an emergency? Well as long as you don't stall it in.....
I don't think I need to go any futher. What it comes down to is the
airplane, it's airworthiness is compromised. Get on the ground at
completely your descretion. Declare an emergency.

>You received the same results (i.e. service from ATC) and that's what counts.

in this case yes but when in ANY doubt, declare it. Would it be
unreasonable for ATC to say "you are #2 for landing" rather than
"everyone get the hell out of the way for the aircraft that declared
an emergency." If there is ANY doubt, declare it. It can only help.

Gerald Sylvester

[Bob Moore]

Andrew Gideon > wrote

> So that would only occur if the capacitor failed "closed"?

No!
Just can't win, can you Andrew.....:-)

Bob Moore

[Corky Scott]

On 27 Sep 2004 13:34:51 -0700,
(Michael) wrote:

>Peter R. > wrote
>> I just received a call from my trusted mechanic early this morning.
>> He discovered that a capacitor failed in-flight, which in turn grounded
>> the mag.
>>
>> This is a bit beyond my limited knowledge of aircraft mechanics and I
>> cannot correctly explain what a capacitor does, but the good news is
>> that it is much cheaper to replace a capacitor than a mag.

When I was an auto mechanic, we still had points type ignition
systems. Each set of points included a condenser, which is another
name for a capacitor.

The points provided the make and break component that caused the coil
to build voltage and discharge it creating the spark that is sent to
the distributer where it was distributed to the spark plugs.

The points sometimes saw as much as 12 volts but most had a ballast
resistor to reduce the amount of voltage the points had to deal with.

Electrons have inertia, once they are in motion, they like to keep on
moving. That's why when you unplug a light, or fan or something that
is drawing current, you see a spark from the plug. The moving
electricity wants to keep moving and attempts to keep the connection
as you pull the plug out.

The same thing happens at the points. When they are bumped open by
the cam that opens and closes the points inside the distributer, the
electricity tries to continue to flow through the points. Without the
capacitor/condensor, they'd arc every time and burn out quickly, or
build up a cap of burned metal, or literally weld themselves together.

The capacitor provides a momentary alternative (but dead end) path for
the electricity when the points open. The capacitors I'm familiar
with consist of thin aluminum foil insulated on both sides by a thin
paper, wrapped up in a roll and encased in a metal cylinder. The
cylinder is usually capped with some ceramic or plastic cover out of
which extends a wire.

Here is an "official" and more complete explanation of a capacitor I
found on the web: "Capacitor (Condenser) - The capacitor performs
several functions. It prevents the points from arcing and prevents
coil insulation breakdown by limiting the rate of voltage rise at the
points. It's primary function is to provide for a rapid decay of the
primary coil current. The capacitor also "third-harmonic" tunes the
coil, raising the peak output voltage and increasing the secondary
voltage rise time. This increases the efficiency and the amount of
energy transferred to the spark plugs. If the coil secondary voltage
rises too quickly, excessive high frequency energy is produced. This
energy is then lost into the air-waves by electro-magnetic radiation
from the ignition wiring instead of going to the spark plugs where we
would like it to go. Voltage rise time should be more than 10
microseconds; a 50-microsecond rise time is OK. Conventional systems
have a typical rise time of about 100 microseconds."

The capacitor is tested by checking to see if the wire is grounded to
the body of the capacitor. If it is, the capacitor has failed. If it
is not, the capacitor is theoretically ok.

The capacitor provides the afore mentioned dead end path for the
electricity when the points open. Remember, the electrons WANT to
keep on moving. They want to keep flowing through the points and can
and will arc to attempt to do this. But the when the points open, the
electrons see the path into the capacitor and jump inside and circle
all the way to the end of the foil, finds it's a dead end and races
all the way back out to the points. But they are open too far now for
the electricity to arc across them so they race back to the end of the
capacitor then back out again in ever diminshing cycles as it looses
energy.

You can see this on the oscilloscope, it's the up and down oscillating
lines that continue in diminishing amplitude after the spark fires.

The person who invented the capacitor was pretty smart. Magnetos
still use points, so they need to have capacitors or the points would
fail quickly. If the capacitor shorts to ground, it grounds out the
the points, which of course fails the magneto.

Corky Scott

[JohnMcGrew]

In article >, Peter R.
> writes:

>at least the
>controller gave you what you needed to have a successful outcome,
>regardless of the side they chose in the bet.

Only after we disregarded his "instructions" and told him what we were going to
do.

John

[Peter R.]

Corky Scott ) wrote:

<snip>
> The person who invented the capacitor was pretty smart. Magnetos
> still use points, so they need to have capacitors or the points would
> fail quickly. If the capacitor shorts to ground, it grounds out the
> the points, which of course fails the magneto.

Thank you for taking the time to expand on the explanation. It is now
coming together for me.

--
Peter

[Andrew Gideon]

Peter Duniho wrote:

> The capacitor is in the circuit in parallel with the normal path of the
> current. If it fails in the closed circuit state, this provides an
> alternate route for the current coming from the magneto, shorting it out
> and
> preventing a spark from being generated. But when it fails in the open
> state, there is still the normal path of the current available for
> shorting out the magneto when the ignition switch is in the off position.
>
> Make sense?
>

Yes, thanks.

- Andrew

[Andrew Gideon]

Bob Moore wrote:

> Andrew Gideon > wrote
>
>> So that would only occur if the capacitor failed "closed"?
>
> No!
> Just can't win, can you Andrew.....:-)

So that would only occur if the capacitor failed sideways?

- Andrew

[Brian Case]

My experience with failed mags is fortunately limited to Fouled plugs
on the runup. However I am aware of 2 interesting incidents involving
Mag's.

1. My flight Instructor was flying departing in a 414. Upon starting
one engine he could just barely get it run it was coughing, sputtering
backfiring, etc. He shut down and brought the Mechanic who determined
that the timing on one of the Mags had slipped. It was firing but at
the wrong time. Sorry I am not a Mechanic so I don't know what would
have happed to cause that. However had my instuctor done a mag check
he would have found that the engine ran fine on one mag and not at all
on the other. lesson Learned if an engine start running rough or badly
in flight a mag check is a worth while check.

2. A local Cropduster pilot had just finished up and was taking his
Ag-Cat back to the home base about 5 miles away. On his Runup he
discovered that one mag had died completely. He opted to fly it back
to base to get it fixed. Upon landing at his home base he 1st took it
to the fuel pump and fueled it. After Fueling he could not get it to
start. The 2nd Mag had failed!

So far my worse experience with a Mechanical Fail has been the nut on
one of the intake valves worked loose in our Tomahawk and the engine
began running rough and lost a couple hundred RPM. We simply informed
ATC that the engine was running rough and we were diverting to the
nearest airport.

Brian
CFIIG/ASEL

[G.R. Patterson III]

Brian Case wrote:
>
> After Fueling he could not get it to
> start. The 2nd Mag had failed!

While possible, it's much more likely that the dead mag was the one with the impulse
coupling. The impulse coupling retards the spark and increases the magneto output to
get the engine started. There is usually only one, and it's usually on the left
magneto.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[alexy]

Ron Rosenfeld > wrote:

>On Sun, 26 Sep 2004 19:06:47 -0400, Peter R. >
>wrote:
>
>>ATC answered, "Thank you and if there is anything you need, please
>>ask." Knowing what she was implying, I kept the "Declare Emergency"
>>call on my mind and ready to use had the engine began to run rough.
>
>Peter,
>
>You handled the problem well and I enjoyed reading about your thought
>process. They were clear and logical, and the TAT teachings obviously
>helped.
>
>However, I think all too often we GA pilots are reluctant to declare an
>emergency. And I know I would have in the situation you were in.
>
>Although you were not in a DISTRESS situation, as defined by the AIM, you
>were clearly in an URGENCY situation. And BOTH are reasons for declaring
>an emergency.

Was this a candidate for a "pan pan" call rather than "mayday"?
--
Alex
Make the obvious change in the return address to reply by email.

[[email protected]]

An open mag capacitor would make the spark very weak, and starting
would probably be impossible on such a mag. However, at higher RPMs
there might be enough spark to make the engine run. It'd raise hell
with the points in short order though.

I'm always surprised that there isn't more emphasis on what to expect
when doing a mag check at different speeds - like at idle which will
show bad points or that bad condenser. At cruise you could find a bad
coil or a harness problem - but you better do that near an airport
just in case. I wouldn't ever do a mag check at full power except on
the ground.

There are some recent ADs involving mag capacitors.

[Michelle P]

George,
Came standard on the M-7-235 with the IO-540.
Michelle

G.R. Patterson III wrote:

>Michelle P wrote:
>
>
>>If you have a Constant Speed prop you will not see the RPM drop as long
>>as you are within the authority of the governor.
>>
>>
>
>Well, when I bought my Maule, I couldn't scrape up the extra $15k for the version
>with the CS prop. :-)
>
>George Patterson
> If a man gets into a fight 3,000 miles away from home, he *had* to have
> been looking for it.
>
>

--

Michelle P ATP-ASEL, CP-AMEL, and AMT-A&P

"Elisabeth" a Maule M-7-235B (no two are alike)

Volunteer Pilot, Angel Flight Mid-Atlantic

Volunteer Builder, Habitat for Humanity

[Ron Rosenfeld]

On Tue, 28 Sep 2004 16:08:38 GMT, alexy > wrote:

>Was this a candidate for a "pan pan" call rather than "mayday"?

Well, yes. But I would just say I'm having a problem and declaring an
emergency. Nothing wrong with the Pan call.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Teacherjh]

> Was this a candidate for a "pan pan" call rather than "mayday"?

I've always thought "pan pan pan" to be silly. If you are in a full fledged
emergency, you (may) need immediate help on the radio, and "mayday" tells
everyone to shut up for a moment. If it doesn't warrant "mayday", then it
probably can be handled (on the radio) without a prefix - that is, a statement
(when the freq is clear) that one needs priority handling should be enough.

If the freq is busy, even a mayday may not get through.

Has anybody found "pan pan pan" useful as a prefix to radio communication?

Jose

--
(for Email, make the obvious changes in my address)

[Paul Sengupta]

"Teacherjh" > wrote in message
...
> > Was this a candidate for a "pan pan" call rather than "mayday"?
>
> I've always thought "pan pan pan" to be silly. If you are in a full
fledged
> emergency, you (may) need immediate help on the radio, and "mayday" tells
> everyone to shut up for a moment. If it doesn't warrant "mayday", then it
> probably can be handled (on the radio) without a prefix - that is, a
statement
> (when the freq is clear) that one needs priority handling should be
enough.
:
> Has anybody found "pan pan pan" useful as a prefix to radio communication?

Well, I'd say that a "pan" call tells them you need priority handling
without
everyone else having to shut up.

:-)

Paul

[Teacherjh]

>>
Well, I'd say that a "pan" call tells them you need priority handling
without everyone else having to shut up.
<<

Well, so does a simple request in English to that effect.

Jose



--
(for Email, make the obvious changes in my address)

[Capt.Doug]

>"Peter Duniho" wrote in message > In addition to the "burp", you should
also >note increased fuel flow or
> higher EGT/TIT temperatures (depending on whether you readjust the mixture
> to compensate for the less-complete combustion). Nothing wrong with
> checking the mags after landing, of course, but I've never heard of a mag
> failing in flight where there was NO actual indication that it had failed.

There were no other indications. Many magneto installations can be tuned so
that there is no perceptible rpm drop during a mag check. At 8500 feet with
normally aspirated engines and with the original EGT probes and gauges in a
heavily used charter airplane, it is possible that there won't be
perceptible differences after a mag failure.

Just wondering, what do you think will be the oil temperature indications of
an engine losing oil? What about cylinder head temps? I know the book
answers and I know the real world answers.

D.

[zatatime]

On Thu, 30 Sep 2004 02:43:30 GMT, "Capt.Doug" >
wrote:

>Just wondering, what do you think will be the oil temperature indications of
>an engine losing oil? What about cylinder head temps? I know the book
>answers and I know the real world answers.


Care to expand on this? My answers would be oil temp going up for a
couple miutes and then going down when there isn't enough oil to be
sensed left in the engine. Cylinder head temps would go up.

I've never read about this in a book and woiuld like to understand
what to expect should it happen.

Thanks in advance if you chose to reply
z

[Capt.Doug]

>"zatatime" wrote in message My answers would be oil temp going up for a
> couple miutes and then going down when there isn't enough oil to be
> sensed left in the engine. Cylinder head temps would go up.

You're on the right track. In 4 oil loss situations that I've experienced,
the oil dumped out over a period of time, not instantaneously. The CHTs may
have risen slightly, and a good gauge should have shown the slight rise, but
the ancient OEM gauges in front of me didn't show it. The oil pressure
dropped off slowly. Most oil lines to the pressure gauge have a small
orifice that restricts oil flow in case the line breaks. I theorize that the
orifice damps out the fluctuations of the pressure changes as air bubbles
make their way through the oil passages. The oil temperature never did rise.
It dropped slowly. I theorize the temperature sensor releases some of the
heat it receives from the oil into the air bubbles passing over it thus
showing a cooler temperature. On the Continental TSIO-520 series, the first
indication of low oil shows up as fluctuating manifold pressure. Air bubbles
passing through the waste-gate controller cause this. On some engines, the
propeller RPMs will indicate low oil before the gauges do as air bubbles
passing through the prop governor cause the RPMs to fluctuate. I just
remembered a fifth time. The engine was a Garrett turboprop. The first
indication was oil pressure. The temp was normal. I was on short final and
simply feathered the engine.

D.

[zatatime]

On Fri, 01 Oct 2004 00:52:11 GMT, "Capt.Doug" >
wrote:

>>"zatatime" wrote in message My answers would be oil temp going up for a
>> couple miutes and then going down when there isn't enough oil to be
>> sensed left in the engine. Cylinder head temps would go up.
>
>You're on the right track. In 4 oil loss situations that I've experienced,
>the oil dumped out over a period of time, not instantaneously. The CHTs may
>have risen slightly, and a good gauge should have shown the slight rise, but
>the ancient OEM gauges in front of me didn't show it. The oil pressure
>dropped off slowly. Most oil lines to the pressure gauge have a small
>orifice that restricts oil flow in case the line breaks. I theorize that the
>orifice damps out the fluctuations of the pressure changes as air bubbles
>make their way through the oil passages. The oil temperature never did rise.
>It dropped slowly. I theorize the temperature sensor releases some of the
>heat it receives from the oil into the air bubbles passing over it thus
>showing a cooler temperature. On the Continental TSIO-520 series, the first
>indication of low oil shows up as fluctuating manifold pressure. Air bubbles
>passing through the waste-gate controller cause this. On some engines, the
>propeller RPMs will indicate low oil before the gauges do as air bubbles
>passing through the prop governor cause the RPMs to fluctuate. I just
>remembered a fifth time. The engine was a Garrett turboprop. The first
>indication was oil pressure. The temp was normal. I was on short final and
>simply feathered the engine.
>
>D.
>
Thanks for the reply!

z

[Dave Butler]

> Many magneto installations can be tuned so
> that there is no perceptible rpm drop during a mag check.

Then they are tuned incorrectly, no? If there's no perceptible drop, how do you
know your P-leads and ignition switch are working correctly?

[Dave Butler]

> If you have a Constant Speed prop you will not see the RPM drop as long
> as you are within the authority of the governor.
> You will see a change in Manifold pressure and eventually a slight drop
> in Airspeed.

Why does the MP change? (disregarding that governors are not perfect) the engine
speed hasn't changed, and the throttle setting hasn't changed. How can the MP
change?