Originally Posted by
Capn Bloggs
Dozy, you heard it wrong.
From Wiki:
It's splitting hairs a bit. The crew neither confirmed between themselves that they had indeed passed Tulua, nor did they tell ATC (who did not have the benefit of radar) that they had passed it. Judging by the report, the first time anyone knew for certain that they'd already passed it was when the FDR data was examined.
That's by-the-by though. The main point I was trying to make was in response to bubbers saying that "the computer chose the nearest R", when the computer could do no such thing.
Reading the report (kindly linked by PJ2), it appears that both the books I read and Wikipedia actually have things slightly wrong.
Originally Posted by Cali NTSB report p.41
The first automation-related error by the flightcrew, the selection of Romeo instead of Rozo, was a simple one, based on the method used to generate a selection of navaids from the FMS data base, using the single letter identifier. All navaids having that identifier are displayed, in descending order of proximity to the airplane. The one closest to the airplane is presented first, the second is further from the position and so on. Selecting R resulted in a display of 12 NDBs, each of which used the "R" as an identifier. Choosing the first beacon presented in this list resulted from a logical assumption by the pilot.
The investigation determined that because of rules governing the structure of the FMS data base, Rozo, despite its prominent display as "R" on the approach chart, was not available for selection as "R" from the FMS, but only by its full name. The evidence indicates that this information was not known by the flightcrew of AA965.
So it would appear that Rozo was not even on the list displayed!
One of the things that was drilled into me in my Air Cadet days was the Navigation Mantra, which is "Check, Cross-check and Re-check".
That this mantra was not followed is in the report:
Originally Posted by Cali NTSB report p.54
9. One of the AA965 pilots selected a direct course to the Romeo NDB believing that it was the Rozo NDB, and upon executing the selection in the FMS permitted a turn of the airplane towards Romeo, without having verified that it was the correct selection and without having first obtained approval of the other pilot, contrary to AA's procedures.
However, given that the whole point of the course change was to expedite the approach quite late in the game - and that doing so increased the workload in the flight deck considerably in other ways too, it is at least understandable.
Apropos of nothing, I'm keeping my comments strictly to the subject of FMS issues because that's the only point I originally tried to raise.