|Title:||Dual electrical failure, Incident involving aircraft SE-LGZ in the air space over Mariehamn, Sweden on 31 January 2003|
|Micro summary:||An independent dual electrical failure on this ATP.|
|Event Time:||2003-01-31 at 0615 UTC|
|Publishing Agency:||Swedish Accident Investigation Board (AIB)|
|Report number:||RL 2004:26e|
|Diversion Airport:||Stockholm-Arlanda Airport, Marsta, Sweden|
|Site of event:||Airspace over Mariehamn|
|Departure:||Stockholm-Arlanda Airport, Marsta, Sweden|
|Airplane Type(s):||British Aerospace ATP|
|Operator(s):||West Air Sweden|
|Type of flight:||Cargo|
|Diverted to:||Stockholm-Arlanda Airport, Marsta, Sweden|
|Executive Summary:||Approximately 15 minutes after takeoff from Stockholm/Arlanda airport, a total loss of electricity occurred in the aircraft’s right electrical system, whereupon all flight and navigation instruments (EFIS) on the right hand side went U/S. In connection with the loss of electrical power, the main warning lamp started to blink, the blue mimic line in the R/H GEN switch went out, the R/H INVERTER and EXIT lit up on the emergency panel. By re-starting (switching off and on) some of the systems, normal electrical function was regained but after a minute or so it was lost again.|
The pilots contacted air traffic control and requested clearance to return to Stockholm/Arlanda. They were radar-vectored for an approach and landing on runway 01L. The pilots did not recognize the problem and did not think that any point in the emergency checklist matched the fault. They therefore elected not to take any further fault-finding steps because of the risk of making the situation worse. The landing was performed without problems and without using flaps.
The electrical failure was caused by two independent faults, of which one arose in an early-version component with known weaknesses. The problem in the aircraft’s electrical system is known to the manufacturer and steps have been taken both by the manufacturer and the aircraft company to rectify it. It would probably have been possible for the pilots to recover full electrical function by cross-connecting from the left electrical system, as becomes partly clear from the emergency checklist.
In SHK’s view the checklist in use is not user-friendly and does not constitute the natural aid to the pilot in identifying a possible fault and taking the most suitable steps from the point of view of flight safety. It is complicated, the logic is not self-evident, the typeface is small, warning panel text is not reproduced as headings for steps to be taken, etc. SHK has noted that there is no international standard for the design of emergency checklists.
The incident was caused by two independent faults in the aircraft’s electrical system occurring simultaneously.
|Learning Keywords:||Operations - Checklists/Procedures|
|Systems - Electrical|
|Systems - Flight Instruments|
|Close match:||EFIS failure, Incident on board aircraft SE-LGX in the air space north-east of Stockholm/Arlanda Airport, AB county, 13 November 2002|
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