The International Cessna^® 170 Association

From FAA Airworthiness Alert system:
A duel (sic) vacuum pump, part numbers, ADVPL211C & ADVPL211CW, was designed by Aero Advantage to provide redundancy. The pump, engine mounted, is driven by two co-axial shafts. However, there have been 14 single shaft failures and 11 duel shaft failures, in a population of 275 sold units. All but two of the failures have occurred with flight time in
excess of 200 hours.
On 05/13/04, Aero Advantage sent an e-mail advising the FAA and the AV WEB announcing that they had several failures and that they had stopped production and any further sales of the pump and closed the doors.

I'd stop production of that pump also with those numbers

Closed the doors.... you mean they went out of business?

I presume that's what was meant. (I didn't create the message, ...I only repeated it word for word as it was submitted to us.) - George