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%5C...plus%20add.pdf