Narrative:

Operating a 'stand-up' revenue flight. Approximate local time was xa:30; and fatigue was most certainly a contributing factor to this incident. Upon checking on with approach control we were vectored through the final approach course (due to opposing traffic) for runway 28R. Visual conditions prevailed; and we both had selected the RNAV (GPS) runway 28R approach in the FMS to assist us with the visual approach. Approach control had turned us back toward the final approach course; and had issued a descent clearance. As to what altitude I do not recall. A vertical speed descent was initiated at approximately 1500ft/minute. Once turned back in toward the final approach course we made visual contact with the airport and the landing runway. At that time we advised approach control that the airport was in sight. We were cleared for the visual approach and told to contact tower. I selected an altitude of 4400ft MSL as that is the traffic pattern altitude for our operations. With the approach already armed in the FMS; I selected (dto) direct to an approach waypoint. The aircraft proceeded direct to the waypoint from a location approximately 2 nautical miles south west of the final approach course. I then selected (vto) vertical guidance to the waypoint; the vto function did not work correctly. The aircraft continued a descent at 1500ft/minute to 4400ft msl. As I tried to correct the problem on the FMS; while the aircraft was proceeding direct to the waypoint; the egpws issued a terrain conflict. 'Terrain; terrain' 'pull up'. At the time our altitude was approximately 5000ft MSL. The crossing restriction over the waypoint on the RNAV (GPS) reads 5500ft MSL. Tower never issued an altitude alert or warning to us. As a result of the egpws warning received; the auto-pilot was immediately disengaged; full power was applied and a climb was initiated instantly as per company policy and procedures. The terrain conflict was cleared. Once past the waypoint we descended at a normal profile to the touchdown zone and landed safely. The chain of events. How the problem arose: 1) difficulty programing the FMS i.e. Lack of training based on different approach scenarios. 2) ATC not issuing a crossing restriction for the visual approach; which had been received on previous flights. Contributing factor: 1) inability of the crew to maintain situational awareness relative to mountainous terrain at night. 2) fatigue. Which I believe truly caused this incident. How it was discovered: 1) egpws alert. Corrective actions: 1) egpws recovery maneuver as outlined by company procedures.

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Original NASA ASRS Text

Title: A DHC8-400 crew had difficulty programming the FMS to fly a RNAV GPS approach. While troubleshooting the FMS entry on final the aircraft continued a descent until an EGPWS warning alerted them about their low altitude position.

Narrative: Operating a 'stand-up' revenue flight. Approximate local time was XA:30; and fatigue was most certainly a contributing factor to this incident. Upon checking on with approach control we were vectored through the final approach course (due to opposing traffic) for Runway 28R. Visual conditions prevailed; and we both had selected the RNAV (GPS) Runway 28R approach in the FMS to assist us with the visual approach. Approach control had turned us back toward the final approach course; and had issued a descent clearance. As to what altitude I do not recall. A vertical speed descent was initiated at approximately 1500ft/minute. Once turned back in toward the final approach course we made visual contact with the airport and the landing runway. At that time we advised approach control that the airport was in sight. We were cleared for the visual approach and told to contact tower. I selected an altitude of 4400ft MSL as that is the traffic pattern altitude for our operations. With the approach already armed in the FMS; I selected (DTO) direct to an approach waypoint. The aircraft proceeded direct to the waypoint from a location approximately 2 nautical miles south west of the final approach course. I then selected (VTO) vertical guidance to the waypoint; the VTO function did not work correctly. The aircraft continued a descent at 1500ft/minute to 4400ft msl. As I tried to correct the problem on the FMS; while the aircraft was proceeding direct to the waypoint; the EGPWS issued a terrain conflict. 'Terrain; Terrain' 'Pull Up'. At the time our altitude was approximately 5000ft MSL. The crossing restriction over the waypoint on the RNAV (GPS) reads 5500ft MSL. Tower never issued an altitude alert or warning to us. As a result of the EGPWS warning received; the auto-pilot was immediately disengaged; full power was applied and a climb was initiated instantly as per company policy and procedures. The terrain conflict was cleared. Once past the waypoint we descended at a normal profile to the touchdown zone and landed safely. The chain of events. How the problem arose: 1) Difficulty programing the FMS i.e. lack of training based on different approach scenarios. 2) ATC not issuing a crossing restriction for the visual approach; which had been received on previous flights. Contributing factor: 1) Inability of the crew to maintain situational awareness relative to mountainous terrain at night. 2) Fatigue. Which I believe truly caused this incident. How it was discovered: 1) EGPWS alert. Corrective actions: 1) EGPWS recovery maneuver as outlined by company procedures.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.