In response to our call for innovations, Greg Stockman sent in his latest patented safety improvement, which he says addresses and corrects several common failures that cause inoperative alternators.
Now installed on a friend’s 250 Comanche and Stockman’s own Cherokee Challenger through the FAA’s field approval process, the device includes a control switch on the instrument panel, which allows the pilot to select one of two voltage regulators to excite the alternator’s field winding. An excited field winding results in the production of electrical power, Stockman explains.
Located behind the instrument panel are two Plane-Power voltage regulators. Either of these voltage regulators alone is capable of commanding the alternator to produce electrical power.
Running from the voltage regulators to the alternator are two separate wires, not one like stock aircraft have, he says. These two wires, along with the two voltage regulators, provide a redundancy similar to having two magnetos firing your aircraft’s engine.
Located at the rear of the alternator are three diodes. Each diode is about the physical size of a Motrin tablet and hardly noticeable in the wiring bundle, he continues. These diodes allow the voltage regulators to command the alternator to produce electrical power, but prevent a defective component from stopping the production of electrical power.
“I’m very excited about the impact this improvement will have on safety for single-engine aircraft,” he says.
You can reach Greg at [email protected] to find out more.
How many times has an alternator ‘failed’ simply due to the regulator or a rectifier diode having failed.
Pat:
Luckily regulators don’t fail often. It has been my experience that field wires fail way more often (usually at the back of the alternator). This failure is usually caused by a combination of heat, vibration, age, corrosion, accidental contact during service, cleaners and such. This failure renders a perfectly good alternator INOP immediately.
Please remember that most new airplanes (w/ glass panels) DO NOT have a vacuum systems. So losing the alternator’s output, for any reason, is a very big deal.
There is also one added benefit not mentioned in the article. If an aircraft is equipped with dual voltage regulators, the set point of the regulators can be slightly different from each other. This allows the pilot to adjust/control the charging voltage at the battery. If you have a chance, please read the battery service manuals published by Gill and/or Concorde. They specify voltage that are based on battery temperature. So one voltage regulator could be set for summer, and the other could be set for winter. This should extend the service life of the battery.
Thank you for posting your comment. I hope my reply makes it to you.
Fly Safe.
Greg
Excellent and well thought-out safety enhancement! Something so simple can give anyone using the system a great deal of comfort. Having lost 3 alternators in flight over the years makes you keep one eye on your watch and the other on the map. It sure would have been nice to flip a switch and get power from the “other side”.
Now for the big question……. how painful was it for you to get your FSDO to grant you a field approval? First born child? 3 pints of O negative blood? A promise to never ask for a field approval again? 50 phone calls into the abyss and a Master’s thesis on the studs used to double stack your voltage regulators?
Please provide us with the name of the person who signed your approval so we can send them a genuine “thank you” for serving the GA community well.
I wish this was a new topic, but it is not. The total collapse of the field approval process has literally stopped innovation and installation of great new technology into GA aircraft.
If you are a person of authority within the FAA and read this response, please tell us all how to better work through the field approval process and bring modern technology to an aging fleet without spending 10’s of thousands of dollars, wasting years of time and getting a one-off STC. Most A&P/IA’s are willing to step up and request field approvals if we knew we could expect a logical and timely response to our efforts. Remember, we work in days and weeks, not months and years. If it can’t happen within the downtime of an annual inspection (a week or two), it is lost.
A “fast track” FAA process is urgently needed for safety enhancements and modern technology like the one described in this article!!
Kenneth:
The East Michigan FSDO did the Field Approval in both a timely AND professional manner. What they added to the installation was very helpful with ZERO burden or delay.
Per the FAA’s website, Mr. Anderson is in charge there. However, a Mr. Haft was our direct contact and go-to guy.
Greg
I wish I would have thought of this modification myself. It should be required in all single engine aircraft equipped with an alternator. The cost to equip you aircraft with this simple Mod. is negligible, but the backup or availability of a second voltage regulator at the flip of a switch, if needed in flight, is priceless. Good thinking Greg.
Richard