My first in-flight mechanical failure

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?

"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.

"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.

"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.

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

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?

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

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.

"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.

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...