The US National Transportation Safety Board (NTSB) last week recommended that Boeing 747-400 operators adopt new non-normal checklist procedures in the event of failure of the cockpit's integrated display systems.
747-400s operated by Singapore Airlines (SIA) twice lost all six EFIS/EICAS interface units (EIUs) - the primary and secondary flight displays - in flight. A Boeing operations manual bulletin issued in February states: "In the unlikely event all six display units [go] blank, cycling the left and centre EIU circuit breakers may recover the display units." Cycling an EIU means pulling the unit out of its mounting and pushing it back in.
The SIA incidents in November 2001 and January this year were solved by cycling the EIUs.
The NTSB proposes Boeing's advice as "a reasonable temporary action until a permanent solution is determined". It advises airlines to incorporate the procedure as a non-normal checklist for ease of reference during such an occurrence.
The cause of the Singapore EIU failures has not been determined.
Source: Flight International
