Non-Fly-By-Wire EGPWS "Assisted Recovery"

[Badmachine]

Unlike fly-by-wire Airbus's and Boeings, can non-fly-by-wire Boeings also implement auto-pilot based "assisted recovery" functions related to the Enhanced Ground Proximity Warning System (autopilot "takeover" of pilot control to avoid Controlled Flight Into Terrain), without physically modifying the aircraft?

Reportedly, fly-by-wire aircraft only require FMC software modifications to implement this "assisted recovery" system, but it would seem non-fly-by-wire B757s and B767s for example, would also require physical modifications to the aircraft to allow an autopilot system to interrupt pilot control.

True?

Thanx

:ok:

[Wizofoz]

"Reportedly" from what source?

I'm not aware of this technology being used or even available in ANY commercial airliner, FBW or otherwise, and I fly a FBW 777.

[catiamonkey]

No such feature on any aircraft. Was proposed on the A380 but never made it past planning. Auto-TCAS did make it into the A380 and is planned for retrofit on the rest. It's just software in the autoflight system. My understanding was that far more mistakes were being made with TCAS than CFIT avoidance.

Maybe you're taking about the stick full back CFIT maneuver specific to FBW Airbus? That's not really specific to GPWS, and would require hardware not only to let auto flight override the pilot, but a complete overhaul of computers, sensors and power to bring up the reliability.

[safetypee]

In theory, non-fly-by-wire aircraft could have an auto pull-up system. It would probably involve automatic engagement of the autopilot, but the implementation of this would be vey complicated and have high certification risk in avoiding hazardous failure / inadvertent engagement. Fly-by-wire aircraft appear to be simpler, but I suspect that these also could have difficulties in certification.

A much simpler alternative is to engage the FD go-around mode with a red level EGPWS warning. This has been considered by some manufacturers (tested in simulation) as it provides a compelling ‘second opinion’ of the required course of action. Human nature often accepts a computed judgement rather than forming an independent judgement – decision aiding. However, these ideas have not yet been developed, reportedly (industry grapevine) due to concerns of passenger liability from cabin injuries during an unexpected manoeuvre; this might say a lot about the priorities of safety in our industry.
Use of auto pull-up with the autopilot engaged in both types of control system is relatively simple, only requiring the EGPWS to trigger a go-around, but ‘passenger’ concerns remain!

Auto pull-up or FD advisory guidance has been identified as a possible solution to reinforce the effectiveness of EGPWS. There have been several indications that crews are complacent with the EGPWS/TAWS operation, and there remain many problems of human performance such as visual illusion or ‘I know better’.

http://www.icao.int/fsix/_Library%5CTAWS%20Saves%20plus%20add.pdf

[ant1]

May be this (http://www.avweb.com/eletter/archives/avflash/1682-full.html#202919) Cirrus article is relevant to this thread.