Re: NTS Board Recommended Improved Black Boxes on Wednesday

From:         Pete Mellor <>
Date:         04 Mar 95 23:27:45 
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It is interesting that there are two glaring omissions in the otherwise 
comprehensive list of parameters whose capture on flight data recorders 
the NTSB wishes to enforce:- 

- Mode of Flight Control System. In the investigation of the A320 crash 
  at Habsheim in 1988, the lack of this meant that there is still no 
  agreement on whether the FCS (referred to as the Electrical FCS, or EFCS, 
  on the A320) was "landing mode" under "normal law", or in "angle of attack 
  protection" (alpha-Prot) mode, immediately before impact. 

- Mode of Flight Management and Guidance System. In the investigation of 
  the A320 crash near Strasbourg in 1992, the lack of this meant that the 
  investigators had to deduce from the flight control surface positions 
  during simulator flights under different modes that the aircraft was 
  *probably* in "heading - vertical speed" (HDG-V/S) or "track - flight path 
  angle" (TRK-FPA) mode. This knowledge was *crucial* in deducing the 
  probable causes of the accident. 

Peter Mellor, Centre for Software Reliability, 
City University, Northampton Square, London EC1V 0HB 
Tel: +44 (171) 477-8422, Fax.: +44 (171) 477-8585, 
E-mail (JANET):