A little engine trouble

I hesitated to even bother writing about this, since so far it seems like
pretty much a non-event. But then I figured, what the heck...hardly anyone
ever actually writes about actual flying, however mundane, in this
newsgroup, so here you go...

The plan was for me to follow a friend down to his mechanic's shop at Tacoma
Narrows (TIW) airport in Washington State. We're both based at Paine Field
(PAE) in Everett, WA, and in fact he ties his airplane down just outside my
hangar. We often trade rides, since neither of us have our airplanes
maintained at Paine Field.

The flight down was uneventful. He flew down in his airplane, while his
wife and I flew down in mine. We got to TIW, picked him up, and headed back
out. Cleared for a northbound, left downwind departure from runway 17, we
took off.

Well, we'd only climbed a few hundred feet when something in the airplane
started making a very strange noise. My friend's wife heard it too. It was
sort of a rapid "growling" sound, lasting a second or two at a time, with
maybe five or ten seconds between. It seemed most likely to be coming from
the engine, but it was subtle enough I couldn't rule out some sort of
airframe flutter. It might have been my imagination, but it seemed like
whenever I heard the sound, there was a little deceleration from the
airplane.

I've owned the airplane ten years now, and have never heard anything like
that out of it. That was enough for me, having read plenty of the "I
Learned About Flying From That" stories in which a pilot ignored a seemingly
minor symptom that quickly turned into something major. So I got a landing
clearance back at TIW, continuing to climb until I was in a position to make
a normal power-off landing, and then of course landed. Once the power was
pulled back, I did not notice the sound again.

The whole situation is very inconvenient. My airplane is now sitting at my
friend's mechanic's shop, where his airplane *should* be sitting (waiting
for its annual inspection). I spent half the day driving back and forth, so
that we could leave his plane there as well (he flew us back to Paine, where
I picked up my car and drove back down to get him). And his airplane is
tied down in transient parking at TIW, because there wasn't a spare spot for
my airplane so I took his (we actually had expected a spot to clear before
he got back, but it didn't).

But somehow, it still seems like the right thing to have done. I haven't
had a chance to get any mechanic (mine or my friend's) to take a look at the
airplane yet. Even though this year's annual was surprisingly expensive
(and that's among some years of some pretty surprisingly expensive annuals),
I secretly hope that something serious is found wrong with the airplane so
as to justify my aborting the flight. But even if the source of the noise
turns out to be something entirely benign, I'm still comfortable in my
decision, and would do it exactly the same again.

Bottom line: another word for "inconvenience" is "adventure". And that's a
much more desirable kind of adventure than the other synonym for the word,
"engine failure". More importantly, I always wondered if I would have
the courage to ignore my desire to get back home and abort a flight when
things didn't seem right. Now I know that I would, and did.

Funny thing though: I've now been stranded three times with this plane over
the years (the other two times were both engine starting problems: once a
dead battery, another time a problem with the "shower-of-sparks" ignition
system). Two of those three times happened at TIW, and it's not like I
actually fly there all *that* often. Spooky...

Pete

p.s. I couldn't help think about how this situation would have affected a
renter. From past threads here, it's clear that depending on the FBO, I
could either have gotten the four-star treatment, with an FBO pilot coming
to get me, or I could have gotten the shaft, being required not only to find
my own transportation back home, but being required to recover the airplane
once it had finally been repaired. I find it odd that the latter sort of
FBO manages to stay in business.

"Peter Duniho" wrote:

Well, we'd only climbed a few hundred feet when something in the
airplane
started making a very strange noise.

Sorry, Pete; you fly a ...?

It might have been my imagination, but it seemed
like whenever I heard the sound, there was a little
deceleration from the airplane.

Did you happen to look at the tach or MAP during any of these events?

But somehow, it still seems like the right thing to have done.

No question.

But even if the source of the noise
turns out to be something entirely benign,

Here's hoping it's not one of those intermittent, "mystery" problems and
your mechanic spots it right away. Keep us posted.
--
Dan
C172RG at BFM

I was out flying the CAP's 172 yesterday when I noticed the same thing. A
growling sound. I determined that it was the soda can air vents getting hit
by the prop wash, or rather, the openings being hit and the cans amplifying
the sound.

What were you flying and could it have been the same thing?

mike regish

"Peter Duniho" wrote in message
...

I hesitated to even bother writing about this, since so far it seems like
pretty much a non-event. But then I figured, what the heck...hardly
anyone
ever actually writes about actual flying, however mundane, in this
newsgroup, so here you go...

"Dan Luke" wrote in message
...
Sorry, Pete; you fly a ...?

Lake Renegade (turbocharged model).

Did you happen to look at the tach or MAP during any of these events?

No. Of course, in hindsight that might have provided useful information.
But even when the takeoff is going smoothly, I'm a "eyes outside" kind of
person (once the proper reading of the gauges has been confirmed during the
takeoff roll, of course).

In this particular situation, my mind was focused on where on the water
would be acceptable for a landing (though, frankly, the Tacoma Narrows are
not generally amenable to seaplane landings in any case, due to strong
currents through there), and on a possible landing back at TIW.

Maybe I could have had my front-seat passenger watch the gauges, to try to
correlate them with the noise. But I personally didn't have the attention
to spare. I would have either have had to keep my eyes on the engine gauges
until the noise occurred, or I would have had to hope to be able to shift my
attention quickly enough to evaluate the gauges in the short period during
which the sound occurred. Neither would have been practical to do, IMHO.

It's a pretty good argument for a data-recording engine monitor. I'll
have to think about getting one of those.

Pete

"mike regish" wrote in message
news:QRXyc.95474$Ly.16002@attbi_s01...
I was out flying the CAP's 172 yesterday when I noticed the same thing. A
growling sound. I determined that it was the soda can air vents getting
hit
by the prop wash, or rather, the openings being hit and the cans
amplifying
the sound.

What were you flying and could it have been the same thing?

Nope...the Renegade doesn't have those kinds of vents, and of course the
prop wash is entirely aft of cabin venting anyway.

I'm not ready to rule out some sort of aerodynamic effect -- for one, during
the annual inspection the fiberglass tips of the horizontal stabilizer were
replaced -- but it sure didn't seem like one to me at the time. My instinct
was that it was an engine issue.

Also, with ten years of experience flying the airplane, if it IS an
aerodynamic effect, it's almost certainly something new since the annual
inspection. Obviously I can't say that I've seen every single thing the
airplane could do, but I'll bet I've come pretty close over the years,
especially in what are otherwise normal situations such as this one.

Now that I think of it, another thing that's new is that I had them add a
second comm antenna. The sound happened in a climbing left turn, so I
suppose another possibility is some sort of vibration from the antenna.
I'll have to check into that.

I will, of course, post follow-ups to report what, if anything, I eventually
learn.

Pete

"Peter Duniho" wrote in message
...

Well, we'd only climbed a few hundred feet when something in the
airplane
started making a very strange noise. My friend's wife heard it too.
It was
sort of a rapid "growling" sound, lasting a second or two at a time,
with
maybe five or ten seconds between. It seemed most likely to be coming
from
the engine, but it was subtle enough I couldn't rule out some sort of
airframe flutter.

Might be the electric hydraulic pump. It will growl if it's flooded with
hydraulic fluid.
Have it checked anyway!
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt

"Peter Duniho" wrote in message
...
"Dan Luke" wrote in message
...
Sorry, Pete; you fly a ...?

Lake Renegade (turbocharged model).


Now I'm envious Pete.... :-)

Rest assured, it was a good call.

As a student I aborted a takeoff due to a couple of bangs on rotation and
nearly went into the grass. Turned out to be the pax seat belt hanging out
the door. The only things damaged were my ego and my rearend from the
chewing I got from my CFI.

Hope you find the culprit and the fix isn't a bank breaker.

Marty

In article QRXyc.95474$Ly.16002@attbi_s01, mike regish wrote:
I was out flying the CAP's 172 yesterday when I noticed the same thing. A
growling sound. I determined that it was the soda can air vents getting hit
by the prop wash, or rather, the openings being hit and the cans amplifying
the sound.

Sometimes odd sounds turn out to be nothing to worry about.

A week ago, I was flying my Ka-8 glider over Andreas village, which is
not far from the airfield. I had just got off a winch launch, and was in
about the first or second thermal, trying to get enough altitude to try
and get out of the area.

I then heard amongst the sound of the wind going past the canopy this
"Bbbbrbrbrrrrrr brrrrrrrrrrr brrbrbrbrbrbrb" sound, which
immediately made me think that it was airframe fabric vibrating in the
wind. It went quiet for a bit. Then I heard it again. Getting a bit
concerned that the glider might have hit something on the launch that
had damaged the fabric, I was thinking of levelling out for a short
while to make a decision.

Then I realised what it was. It was the sound of motorcycles
accelerating up the Sulby straight about three or four miles away...it's
amazing how well sound travels when you're above what's making the
sound.

(The nice thing about the Ka-8 is that I can hear powered aircraft in
the vicinity).

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

As a student I aborted a takeoff due to a couple of bangs on rotation and
nearly went into the grass. Turned out to be the pax seat belt hanging out
the door. The only things damaged were my ego and my rearend from the
chewing I got from my CFI.

Had something like that happen... my instructor forgot to tell me that
150's sometimes get a violent nosewheel shimmy during the takeoff
roll... well, I found that out for myself on my first solo... pushed
the power up, and a few seconds later the whole plane started
shaking... aborted the takeoff thinking it was going to come apart on
me. Course, he just tells me to keep the weight off the nose, so my
three flights were done soft-field style with the nose up as soon as
it would go.

On Sun, 13 Jun 2004 00:04:25 -0700, "Peter Duniho"
wrote in Message-Id:
:

Well, we'd only climbed a few hundred feet when something in the airplane
started making a very strange noise. My friend's wife heard it too. It was
sort of a rapid "growling" sound, lasting a second or two at a time, with
maybe five or ten seconds between. It seemed most likely to be coming from
the engine, but it was subtle enough I couldn't rule out some sort of
airframe flutter.

From the description of the noise, it would be consistent with some
sort of vibratory resonance. Having actually experienced it, can you
rule that out?

It might have been my imagination, but it seemed like
whenever I heard the sound, there was a little deceleration from the
airplane.

As another has suggested, the tach/MP gage should help in diagnosing
any loss of power associated with the noise.


--

Irrational beliefs ultimately lead to irrational acts.
-- Larry Dighera,