Jetstream 4100, G-MAJA
Whilst on final approach to Wick Airport, the crew lost visual reference with the runway and commenced a go-around. During the missed approach momentary blanking of the electronic flight instrument system (EFIS) displays occurred but the standby instruments continued to operate normally. During the subsequent approach a similar event occurred, but only the co-pilot’s displays were affected.
The crew diverted to Aberdeen Airport where the weather was better. During the diversion VHF communication difficulties were experienced, but the aircraft landed without further incident.
The operator, in consultation with the aircraft manufacturer, determined that the right EFIS display blanking was caused by a loss of electrical power to the right essential busbar. The right power distribution unit was removed and sent to the manufacturer for investigation.
The aircraft manufacturer considers that the transient blanking of the left EFIS displays was caused by an unrelated failure of the ‘transzorbs’. (These are installed in the windscreen heat system to protect avionics equipment from the effects of windscreen static).
The VHF communication difficulty was explained by a separate fault on the left communication unit. The right communication unit was unpowered as a result of the right essential busbar failure.
Jetstream 4100 G-MAJA 02-14.pdf (47.10 kb)