Diamond.

The following information is derived from the FAA's Service Difficulty Reports and Aviation Maintenance Alerts.

ELECTRODELTA VOLTAGE REGULATOR

Loose Circuit Boards

A Diamond DA-42 experienced a double alternator failure. Troubleshooting discovered circuit boards in the ACU/voltage regulator (p/n VR2000282) were loose and causing "shorting and random spiking of the alternator outputs." Replaced right side of shunt fuse (p/n 263003). When the fuse is open, the ACU doesn't sense voltage, causing extreme alternator output.

Part total time: 2626 hours

DIAMOND DA42 TWINSTAR

Worn Alternate Air Intake

During a 500-hour inspection, a suction sleeve from the alternate air valve was found inside the air filter. The suction sleeve flange and valve body groove were worn to the point the suction tube was allowed to migrate out of the alternate air valve into the air filter.

Part total time: 1453 hours

DIAMOND DA20-C1 KATANA

Loose Fuel System B-nut

The aircraft developed a significant fuel leak. Inspection revealed a loose jam-nut, which was less than finger tight, causing fuel to flow freely past the shutoff valve packing. This appears to have been triggered by operation of the fuel shutoff valve at a different time.

Part Total Time: 3359 hours

DIAMOND DA20-C1 KATANA

Fuel Shutoff Valve

During a scheduled 1000-hour inspection, the emergency fuel shutoff arm was removed to inspect a valve known to loosen up and produce leaks. The valve nut jam nut was less than finger tight, with no Loctite or self-locking mechanism by design. The nut was removed, shaft cleaned and reassembled with Loctite blue.

Part total time: 3950 hours

DIAMOND DA42 TWINSTAR

Faulty Gear Indicator

Nose gear indicator bulb would not illuminate, despite test indicating a functioning bulb. Cycled gear and received normal gear indications, but was able to duplicate the problem in which the light did not illuminate after multiple cycles. Found nose gear down lock pin (p/n D6032337000) not rolling and worn. Replaced pin JAW SB MSB-42-062/1.

Part total time: Unknown

DIAMOND DA42 TWINSTAR

Leaking Fuel Pump Filter

Low-pressure fuel pump assembly (phi D6428110000) leaked brand-new, out of the box., with one drip every 5 to 10 minutes. The drip appeared to be leaking from the filter assembly attached to the bottom of the pump. Replaced filter; ops check okay.

Part total time: Unknown