After further thought and research, with help from the most useful web site EGPWS.com, it is unlikely that Terrain Ahead alert was given. The aircraft appeared to remain just above the terrain clearance floor (TCF) boundary (approx 100ft/nm above field elev out to 4nm), but if the erroneous approach had progressed further, then an alert and warning could have occurred … but when.
Assumptions:-
- that EGPWS was fitted to the aircraft and it was serviceable (UK registered aircraft / JAR operation) – (N.B. in a recent European MD 83 CFIT accident the EGPWS was reported as being unserviceable).
- that the FDR was inspected for an EGPWS event; also note that the EGPWS computer will store up to 100 events in its memory.
The TCF warning boundary depends on the mod state of the EGPWS software – operators should check that they have the latest version and an updated terrain database.
It has not been possible to establish if the obstacle mode was activated (free mod for all operators). However, even if this aircraft had the facility, then an alert was unlikely as I understand no obstacle database info is available for Ireland. (I wonder why? Normally Honeywell will use any/all approved data where available – problems with co-ordinate systems etc – what’s the problem with Ireland?)
If all of the obstacle mode requirements were available, then an alert would have been given some 60 sec ahead of the aircraft (circa 3nm).
If EGPWS had been considered during the investigation then the issues of obstacle mode activation / data base availability might have resulted in a safety recommendation – i.e. EASA to ‘recommend’ that all operators activate the obstacle mode (no cost?).
Consider a future scenario where ATC might not be as vigilant as in Dublin – EGPWS would be the last chance, and the obstacle mode would give the earliest alert.
Of similar intrigue, as a UK registered aircraft the UK AAIB could have been involved – did they miss the EGPWS issues also?