Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

757 system question

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web

SLUF4

Well-known member
Joined
Nov 21, 2005
Posts
1,122
I came across the CVR recording of Aero Peru 603 on youtube-pretty disturbing-but the captain and FO kept referencing the Rudder Ratio and Mach Trim during this scenario. What information would they be trying to gather from the fact that the rudder ratio and mach trim weren't engaged; or were those just the only messages that came up on the EICAS? I've not flown anything with a rudder ratio so I'm not exactly sure what that does.
 
Last edited:
Rudder ratio allows large rudder movement at slow speeds and limits it at higher speeds. The light means you may not get full deflection. On the 767 you have a crosswind limit for landing with the light on.
 
Rudder ratio allows large rudder movement at slow speeds and limits it at higher speeds. The light means you may not get full deflection. On the 767 you have a crosswind limit for landing with the light on.

OK thanks; I guess since the system was so screwed up the rudder ratio failed.
 
Like Junkflyer said above. The Rudder Ratio allows for large deflection of the rudder at low speeds, and conversely limits rudder deflection at high speeds. On the 757 the rudder ratio light typically is related to a left hydraulic system problem/failure.
 

Wow. God bless 'em. It's really amazing they stayed in the air as long as they did because it sounds like they never got much higher than 1000' AGL. Assuming they never really got to 9700' based on Lima's elevation.

Easy to armchair quarterback so this is really just a synopsis on what I gathered and learned.

They had several clues that their ADCs were giving them invalid information but continously tried to use systems that received information from them (A/T, Vertical MCP modes, etc.).

They also had the GPWS and SPS systems giving them information that could have helped diagnose their true situation. It seemed the Captain became very fixated on the very instruments they knew could be suspect. It seems like the FO had a gut feeling with his references to ATTITUDE and ENGINE instruments.

Lastly, their Radio Altimeter could have provided some information that could have helped.

Never underestimate the value of good systems knowledge, a good preflight inspection, watch out for "tunnel vision," and remember PITCH + POWER = PERFORMANCE.

There but for the Grace of God...:(
 
Last edited:
Using their ground speed readout and radio altimiter with attitude and power settings might have got them down but they certainly had enough distractions with all the warnings to make it difficult.
 

Latest resources

Back
Top