I am pondering developing an inexpensive, resettable, total airframe/engine digital elapsed time meter. Powered from on board batteries, draws about 3 ma, but only while 'on'.... weighs about 10 grams, plugs into any "Y" in the system, and reads continuous total "on time" to tenths of an hour.

Couple of questions for ya'll.....First, anyone think this would be of any benefit to help manage engine run time, airframe, battery usage times?
Second, if you think it would be a benefit, what would be the "ouch" price for such an accessory???