Winter Flying Operations

(see also Winter Operating Procedures, in the Official Documents section of the library)

Some Suggestions for Winter Ops Procedures

1. 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.

2. 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.

3. 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.
   
   
4. 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.

5. 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.”  

6. 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;

7. • 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 (former), 455H