- Engine pre-heat:
The red dragon propane fired pre-heater is back in the club’s storage
box. It could be of use, in the event that Reliant’s electricity
is out, or if a member finds the plane he plans to use has been left
unplugged and it’s too late for a pre-heat from Reliant.
It might seem tempting to take the Red Dragon unit along on a trip to
an out-of-the-way field where services may be unavailable. This
does not look like a viable option when we consider that it is a
violation of Federal Law to carry any propane cylinder (whether full or
empty) in an aircraft. In order for one of us to make use of the
Red Dragon while “away” he would have to obtain a small “Bernz” type
cylinder at the destination (we have an adapter for the small
cylinders) and then he would need to dispose of the cylinder in an
approved fashion before departing.
- Guidelines for pre-heat:
Pilots who elect to use a fuel-fired unit to pre-heat the plane’s cabin
should keep in mind that this procedure fills the cabin with large
quantities of CO and CO2.
Some authorities now recommend using pre-heat whenever the temps go
below 40 Deg. F. There’s an excellent article on Winter Ops in
the latest issue of Aviation Safety. I’ll provide some copies for
the Wednesday December 10, 2008 meeting.
- Priming:
I’ve found that it is, most often, better to prime too little initially
than to use too much prime. With this in mind, on a warm engine,
I’d start off with, say, four shots of the manual primer or only two
seconds worth using 455H’s electric primer. If the engine doesn’t
start promptly one can always try a bit more prime on the next
attempt. I used to think that “You can’t flood the engine with
the primer.” I’ve found out I was wrong. It is
especially easy to flood 455H this way. By the way, when our
planes’ engine heaters have been plugged in for several hours you
should use the warm weather starting procedure. This means the
engine will start best with the least amount of priming. Simple
rules on this; learned the hard way;
- If the engine is cold, Ice cold, on a winter day, Use seven
shots of prime.
- If the weather is warmer and the engine is cold (hasn’t been
run for hours or days), use five or six shots of prime.
- If the engine is still warm (been run within the past hour in
summer or within the past half hour in winter) Use four shots of prime.
- Using the Starter:
Continuing to crank the engine when it does not start promptly is very
hard on the starter and the entire electrical system. In winter
the battery has much less capacity (decreases linearly with decreasing
temps below + 70Deg. F.). The load on the starting system is
greatly increased due to congealed oil and the greater stiffness of the
engine due to decreased clearances. Persisting with futile
cranking in this way can run down the battery to where it is unable to
provide a start at all after less that a minute of cranking.
Run the battery down severely, even a few times, and it will no longer
take or hold a charge. New batteries are expensive and if you’re
stuck at some distant field there may be days of delay in obtaining the
appropriate replacement. Lycoming recommends cranking for no more
than five seconds and following this up with a five minute rest before
trying again to start the engine.
- De-icing procedures:
The FARs used to state that we could “Polish the Frost” on the plane’s
flying surfaces as an alternative to removing it. This rule
has been changed. The surfaces are now required to be “Free
of Frost.”
- Jump Starting:
Oh boy! Is this ever a topic fraught with hazards. The
short answer is NO WAY, NOT EVER! Jump starting with a dead
or severely discharged battery will almost always lead a pilot into
real trouble. You may get off the runway only to find yourself
with a total electrical system failure a short time later; Maybe at
night…Maybe in IFR. Been there, had that. This is no BS or
bureaucratic Chickenshit; you’d better believe it’s a really bad
move. If the battery is just a tad down, say, it’s cranking
the engine, but only just, then, you might get away with using a
booster. If the battery is heavily discharged to where it can’t
turn the engine over at all, the only
options are;
- Take the battery out of the plane and slow charge it for
several hours, preferably, overnight or;
- Buy a new battery.
If you talk with Reliant’s maintenance
chief, Steve Disorbo, about this topic you’ll get quite an earful of
the truly bad experiences he’s had and seen others have from this
misstep. Sure, you’ve used a booster to start your car, we all
have. So, what’s the big deal? Simply put, AIRPLANES AREN’T
CARS. When your car breaks down on the road, you’re stuck…on the ground. When
your plane’s avionics, lights and back-up vacuum source quit in-flight,
where does that leave you?
It seems like such an innocent little operation -- using a booster
battery to salvage a flight from being cancelled, or worse, from being
stuck away from home, due to a dead or severely run-down battery.
How can this cause so much trouble? First off, aircraft
batteries, because of the need for lightness, (They’re made with
LEAD!), are rather fragile. They can’t take the kind of abuse car
batteries often endure. A single attempt to rapid-charge at high
amperage can destroy an aircraft battery.
When we use a booster to start the engine, there is, temporarily,
enough juice to spin the starter, but the plane’s battery is still
deeply discharged. In this situation one of two scenarios are
likely; If the battery is so flat that it hasn’t enough voltage to
energize the alternator, then getting the engine running will not
produce any electrical output – you will have no avionics, no lights,
no nothing. If, on the other hand the battery retains just a
little juice it will be able to get the electrical system up and
running once the engine is started, (With its magneto ignition, the
engine will run just fine with a dead battery.) The plane’s
charging system then takes over. This system will try really
hard, too hard, to recharge the battery. Now, you might
think, you’re home free. On the contrary, your troubles are just
starting to really grow.
The charging system knows no subtlety; given a badly run-down battery;
the charging system will pump juice into the battery at its maximum
rate – about 70 Amps or more in our planes. The result can be to
cook the battery, boiling off the acid…Maybe fill the cabin with highly
toxic fumes in the process. Maybe overload the alternator and
burn it out…Maybe blow out the Voltage Regulator. The same
results would prevail even if we avoided using a booster battery by
hand propping the engine. Any way it shakes out, you are going to
suffer a total electrical failure. What a way to commence a
flight.Of course, all this is guaranteed to make your day. I have
experienced all of the above, firsthand. So, this is not
just “hearsay” or some old hangar flying tale.
Respectfully submitted by; John Barrett, Maintenance Officer,
455H