PPRuNe Forums - View Single Post - EC155 incident, SNS, 6 Nov 2013
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Old 13th Jul 2014, 17:02
  #43 (permalink)  
212man
 
Join Date: Oct 1999
Location: Den Haag
Age: 57
Posts: 6,266
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Like JimL I'm a little surprised there are no recommendations at the end, which is sad given the severity of the incident. Bear in mind that at 184 ft ASL, the Clipper is a 'giant' in the SNS and a departure from most other decks with the same profile would almost certainly not have had the same outcome.

If I had access to the FDR data, one of the parameters I would like to look at is the FTR discrete to see how the FTR was being used in the initial take off. I carried out the first offshore night (and day) take-offs and landings in the EC-155, and came away from the session with a huge sense of how much safer an exercise it was with the built in AFCS attitude logic. From the hover the forward cyclic input is made using the follow-up trim, not using the FTR. During the subsequent acceleration the aircraft attitude changes automatically to an 80 KIAS climbing attitude. The follow-up trim moves to the long term attitude mode from 30 KIAS, with hysteresis, to 40 KIAS and the only pilot input required is a quick 'left beep' on the cyclic 'beep' trim to correct the roll attitude (4 degrees right wing low, in nil wind). Using the FTR cuts out this natural transition process and I can't think of any reason why it would be used in those circumstances. It also gives the sense of the aircraft being a little unstabilised - particularly in roll - and I wonder if the flight crew's comments reflect this?

I also created a set of offshore performance graphs, using the basic PC2 performance as the datum, but with a 250 kg delta from the MTOM (then 4,800 kg) to ensure adequate AEO performance. In other words, we were never above 4,550 kg on departure offshore - but could be lower when the raw PC2 mass was lower than 4,550 kg. When I look at the PC2DLE masses, I do wonder how much attention was given to the AEO performance.
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