Quote:

Now, with all the fancy IRS stuff the biggest problem is a fat finger hitting the wrong number on the computer keypad.

You once again name it, Lou. Like mentioned in other threads around these forums, the situational awareness and the plan to "stay ahead of the plane" doesn't always succeed. And even the fancy glass cockpits are only as good as the guys looking at it.

[edit]3.12      Buga, Colombia – B-757-200 –N651AA – 12/20/95

The Buga accident involved American Airlines flight 965, a Boeing B-757-200 turbofan on a regularly scheduled FAR Part 121 flight from Miami, FL to Cali, Colombia.  The aircraft impacted a ridge on San Jose Mountain, which rises above the town of Buga to 12,900’ MSL at its highest point, at approximately the 8960’ elevation, on a heading of 221o magnetic, while the aircraft was in approach configuration.   Impact was 30.4 NM from the Cali VOR facility.  Of the 167 persons aboard, only four passengers survived with serious injuries.  Weather in the accident vicinity was classified as dark night, VMC.

The Cali airport lies in the middle of a valley between two mountain ridges.  The crew of flight 965 were expecting to fly an ILS approach in which they overflew the field, circled back and landed on the northbound runway (designated 01).  However, because winds were calm, the Cali approach controller offered the crew the option of a “straight-in” approach to the opposite end of this runway (19):  “would you like the one-nine straight in?”  CVR transcripts show the first officer said to the captain: “yeah, we’ll have to scramble to get down (but) we can do it.”  The captain then replied to ATC:  “Yes sir, we’ll need a lower altitude right away, though.”  

The VOR/DME approach to Cali Runway 19 is a non-precision approach starting at the Tulua VOR facility, 43 NM from the Cali VOR at an altitude of 14,900’ MSL.  Beyond Tulua, aircraft follow a heading of 200o magnetic and descend to 5000’ MSL.  Following the contours of the valley, they then turn to a heading of 190o magnetic 21 NM from the VOR, maintaining a 5000’ MSL altitude until reaching a navigational fix 16 NM from the VOR.  At this point, they descend to the 3900’ MSL minimum descent altitude; the ROZO non-directional beacon (NDB) is the signal for aircraft to begin final approach.  

Because there was no terminal radar at Cali, ATC had to rely on pilot reports for information on aircraft position, and requested that flight 965 “report (passing) Tulua (VOR).”  The flight crew, after some initial confusion, realized that ROZO was the final approach fix, and asked ATC “can 965 go direct (to) ROZO and do the ROZO ONE arrival (procedure)?”  ATC replied “Affirmative,” but then reiterated “Report Tulua and 21 miles (the point at which the approach course turns), 5000 feet.” (25)

To slow their airspeed and increase their descent rate, the captain extended the aircraft’s speed brakes at this point, and tuned the flight management system to ROZO by entering an “R” on its keyboard.  Post-crash investigation shows the flight management computer responded with a list of the 12 nearest navigational facilities, ranked in order of distance from the aircraft, having call signs beginning with “R,” together with their latitude/longitude coordinates.  Unknown to the captain, this list did not contain ROZO; it was not entered as such in the flight management system’s memory.  Without bothering to verify its position, the captain selected the topmost facility on the list, assuming it was ROZO.  Unfortunately, it was the ROMEO NDB located in Bogota, 130 NM away. (26)

Once this selection was made, the aircraft began a sharp, 90o turn to the east, heading towards ROMEO.  It was just about this point that the aircraft passed over the Tulua VOR.  Because Tulua was no longer an active waypoint for the flight, it was not displayed on the flight management system, and the crew was unaware it had been crossed.  For reasons that are unclear, the crew did not notice the aircraft had veered sharply off course for about 45 seconds, and then took another 45 seconds to take appropriate corrective action.  All the while, the aircraft was descending.

Cali ATC, realizing the flight should have passed Tulua, but had not reported doing so, then asked “distance now?”  The captain responded “distance from Cali (VOR) is 38 (NM).”  Cali ATC acknowledged, but did not question the report.  Since Tulua is 43 NM from the VOR, it had clearly been passed.  Post-crash investigation showed the controller in question had command of the English language sufficient to engage in routine ATC exchanges, but apparently not enough to raise detailed questions to the crew of flight 965 regarding position and heading as they strayed off course. (27)

Over the next minute, the CVR shows the crew realizing they are heading away from Cali.  The captain says:  “Where are we?  Come right … go to Cali … we got (expletive) up here, didn’t we?”  The first officer then disengages the flight management system and initiates a manual turn to the right of approximately 90 degrees, the end result of which places the aircraft back on the initial approach course.  Unfortunately, the excursion off the approach course had taken the aircraft well beyond the confines of the valley containing the airport.  Still descending, N651AA was now dangerously close to the peaks on the east side of the valley.  Eventually, the aircraft’s GPWS begins to sound a “Terrain! Terrain!” alert, followed quickly by a “Whoop! Whoop! Pull Up!” warning.  The crew’s reaction was immediate and decisive; the nose was pitched up and maximum throttle applied.  But the speed brakes remained deployed, a factor which negatively affected the aircraft’s climb rate.  Eleven seconds after the initial alert, the aircraft impacted San Jose Mountain. (28)

N651AA was equipped with CVR, FDR and GPWS.  Table 13  presents altitude and elevation information for this accident.  This information is presented graphically in Figure 12.[/edit]
from: Investigation of Controlled Flight into Terrain
U. S. Department Of Transportation Federal Aviation Administration (FAA)

The last highlighted part was done intentionally, to show that even some well trained crews may, when getting into stressful situations, profit from certain "laws" to apply, without their interaction because their minds are just full of a flashing "get out of here, now!" then, not recognizing some basic and (sadly) lethal circumstances.
The only clear mind on a plane with the (not test) “Whoop! Whoop! Pull Up!” sound active is the one in those little chips while all the others (at least partially) revert back to to an instinctive (and therefore not always logical) behaviour, while physical laws stay "logical" all the time.
That's my personal viewpoint, well described by this incident which started with "just" a too fast finger on the FMC. Not trying to play smart though.