Windshield Heat and the PA-46

I’ve been a part of many prebuy inspections on PA-46 aircraft lately, and it seems that the Windshield Heat is the elephant in the room during the prebuy. If the windshield heat does not work properly, then someone gets to write a $30,000 check to fix the problem.  Who gets to write this check is usually the subject of much debate in a prebuy, and it often derails the purchase process leaving scars, broken relationships, and lots of spent money.  The key is to know the facts beforehand and to have lots of communication that is written down.

Is it an airworthy item?  Absolutely!  Any mechanic worth his salt will tell you that the windshield heat is required for flight into icing conditions, and as such it is required on the PA-46.  Despite the fact that I’ve actually used the Windshield Heat only once or twice in a decade doesn’t matter.  On that one flight where the chips are down and I need all available resources…that’s when I want everything working on the airplane.

That dang purchase agreement… I HIGHLY recommend that a buyer have a clause in the purchase contract that reads something like this, “All airworthy items and installed equipment shall be operational at delivery”.  I recently got completely screwed by an unscrupulous seller/broker by not having a good purchase agreement.  Verbal agreements are worthless…a well-written agreement is absolutely required!  If you are the buyer, you want to know that the seller will deliver a good airplane prior to you spending money paying for a prebuy for an airplane that you won’t buy due to the seller backing out.  If the seller won’t sign a quality purchase agreement, rest assured he is hiding something and hoping for an unwary buyer. The best airplanes on the market are sold by sellers who are rich in character, have loved their PA-46 for years, and want the next owner to love “their bird” as much as they did.  Although they don’t want to pay $30k for a windshield at sale, they will do so knowing it is the right thing to do.  Another option is to determine the operational capability of the Windshield Heat prior to signing the purchase agreement and then negotiating.  If there’s only 12 amps on the Windshield Heat test, and the buyer lives in Southern Florida and is planning to fly routinely to the Bahamas, he won’t care about the windshield heat from an operational standpoint, but he won’t want to lose the value at the next sale.  Sometimes a “deal” can be struck splitting the cost.  Purchase agreements are always negotiable before signing, so don’t neglect to discuss it closely with the buyer/seller.

How to check out the Windshield Heat: Whether you are the buyer or the seller, you need to know how to find out if the windshield heat is working or not. Basically, you are looking for the amount of amps that the windshield heat extracts from the electrical system.  If few amps flow when turned on, then resistance exists and the windshield will need replacement.  Start the airplane and rev the engine up so the electrical alternator/generator is putting out a good amount of amps.  You don’t want to check the system at idle because the amp draw won’t go up due to the alternator/generator not being able to produce.  Better yet…go on a flight and do the test in the air.  If you are flying a piston PA-46, turn OFF one alternator so you have a single amp reading in the cockpit; if in a Jetprop or Meridian, the Generator will be the only source of electrical power, so there’s no need to turn anything OFF.  Note the amp reading on the amp gauge, and then turn ON the Windshield Heat.  Note the increase in amps.  The amps should increase by 13 amps (or more) in LOW and when you switch to HIGH, you should get an additional 10 amps.  A detailed description of this procedure is listed in Section 9, Supplement 2 of the POH.  Be sure to read all of Section 9 as it is really good reading for the PA-46 pilot.

The gray area: If the amp draw is lower than 13 amps in LOW or less than 5 additional in HIGH, you are not getting proper heat to the windshield.  When the amp draw is less than 8, there is no debate…the windshield needs replacement.  If it is between 8 and 13, you are in the gray area.   I’ve never seen a windshield “get better with time”, and if it is producing less than 12 amps, it is probably about to take a nose-dive and completely fail.  Buyer be warned.

Another way to check out a windshield is to use an infrared camera.  I’ve turned to using the infrared camera as an excellent source of “supporting documentation” when buying or selling.  If the amps are low but the infrared image shows good coverage, then I’ll certainly not make a big deduction at sale, or will recommend not replacing a windshield if the owner is “on the fence”.

You need to know: Whether you are the buyer or the seller, you need to know if the windshield heat is working or not.  In fact, I think this should be one of the BIG questions to ask during initial conversations before the agreement is even signed.  You do ask about Damage History, Original Logs, and Paint/Interior quality, right?  Well, I suggest you ask the seller if the windshield heat works as well.  A new interior or paint job on a PA-46 is FAR less than $30k, and it is the subject of much discussion in the initial stages of the buying process.  As a seller, you need to know if he windshield heat is working so you can adjust your expectations at sale.  If the buyer uses a reputable maintenance provider for the prebuy, the windshield will be inspected.

There are LOTS of “gotcha’s” when buying or selling a PA-46, and the windshield heat is probably the #1 issue discovered at prebuy.  Make sure you are aware of the condition of the PA-46 you intend to buy or sell.  As the the old adage goes, “He who has the most information usually wins!”

About Joe Casey

ATP, CFI, CFII, MEI, CFI-G Commercial Pilot - SE, ME, Rotorcraft, Glider US Army AH-64 Pilot and UH-60 Instructor Pilot and Instrument Flight Examiner
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