SA no. 10: Operation with a battery that is not fully charged
In the course of the safety investigation concerning the accident involving the aircraft DynAero MCR-ULC, HB-WAR, on 13 December at Locarno Airport (LSZL) the Swiss Transportation Safety Investigation Board (STSB) identified a safety deficit and issued safety advice N° 10 in its final report no. 2313.
Zielgruppe(n)
Owners and operators of aircraft that rely on electrical systems which are absolutely essential for the continuation of a flight
Safety advice
It should be ensured that crews are informed of the potential consequences of taking off with a battery that is not fully charged and that corresponding procedures for checking the charge state of the battery are described in the AFM.
Safety deficit
The fuel supply in the MCR-ULC with a Rotax 914 engine is provided by two electrical fuel pumps. In the event that the generator or rectifier regulator fails, the fuel pumps can continue to operate for a maximum of 30 minutes with a fully charged battery before they fail and the engine subsequently cuts out. For this reason, it is important that the battery is fully charged before every flight.
In the procedures described in the MCR-ULC’s aircraft flight manual (AFM) and that are carried out on the ground before a flight, no provision is made for checking the charge state of the battery. Furthermore, the potential consequences of taking off with a battery that is not fully charged are not described in detail.