PPRuNe Forums - View Single Post - Here's something to keep you at the edge of your seat
Old 30th May 2020, 18:15
  #20 (permalink)  
Uplinker
 
Join Date: Nov 1999
Location: UK
Posts: 2,486
Received 95 Likes on 56 Posts
This illustrates why the Airbus FBW designers fitted TOGA switches that can only be manually activated by pushing the thrust levers fully forward.

The problem with having TOGA switches on the thrust lever handles is that you can press for TOGA without pushing the levers forward, and believe TOGA will result. You should also push the levers forward, but as we have seen too many times; when things start going wrong, the human brain can shut down when it cannot understand what is going on, and things get missed. I suspect that having pressed the TOGA switches, the PF believed the engines would spool up and his brain capacity was full while fighting to understand the situation and control the aircraft, so he did not check the thrust.

I believe Airbus designed their thrust control system to avoid this problem. Also, by not having the levers back driven, Airbus pilots are required to look at the N1/EPR gauges to confirm thrust changes and not rely on the proxy of moving levers: So they keep in practise of looking at the gauges, which of course is good practice anyway.

Another point is that if the approach conditions are blustery with significant crosswind and turbulence, it is useful to take manual control much earlier than 470' agl. 7 miles gives one time to "get in the groove" of blustery weather conditions and get your responses up to speed before getting to short finals and the flare

Last edited by Uplinker; 30th May 2020 at 18:27.
Uplinker is offline