Date: 201502
Local time of day: 0601-1200
Location: SKBO.Airport, FO
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight phase: Initial Approach
ATC / advisory: TRACON SKBO
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Terrain Warning; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: Captain-PF; FO-PMFiled to fly MQU1A arrival into SKBO. Prior to MQU; FO listened to ATIS and reported landings to runways 13 left and right. We briefed approach to ILS Runway 13L.Approaching MQU; controller directed turn direct to VULAM. Weather radar and visual sighting indicated a large thunderstorm cell over VULAM. FO informed controller we could not proceed to VULAM due to weather. Controller next directed us to proceed direct to Bogota VOR (BOG) and maintain 310 knots and descend to 14;000 feet. Airport Briefing Page lists speed restrictions of IAS 270 KTS below FL 250. Approaching 14;000 feet we were handed off to approach controller. Approach controller assigned 250 KTS and approach RNAV RWY 13R. We were also cleared direct to NEPOP. At this point I felt slightly rushed. I loaded the RNAV 13R approach and selected the NEPOP transition. As pilot flying; I briefed the approach. The approach loaded and appeared in the box as follows. Line 1- NEPOP Procedural Hold at 13;000 feet; Line 2- NEPOP at 12;000 feet; Line 3 URULO (FAF) at 10;000 feet; Line 4- RWY13R. Knowing the controller did not expect us to enter a Procedural Hold at NEPOP; I attempted to line select Line 2 (NEPOP at 12;000 feet) to Line 1. The box did not allow that action. At this time I elected to concentrate on slowing the airplane down for the approach. I directed the FO to work at getting the correct sequence of waypoints for the intended approach. The FO thought he had solved the problem by line selecting Line 3 URULO to Line 2. This action displayed the proper sequence of NEPOP followed by URULO. By this time the aircraft was in the approach mode since flaps 1 had been selected. When VNAV was selected VNAV PATH displayed in FMA. Thinking the approach was correctly sequenced; I directed the FO to set 9;100 in the MCP altitude window. The autopilot is on. Soon the autopilot started a slow descent. Within a few hundred feet we broke out of the clouds. At this time; we saw the airport and all surrounding terrain. At this time I suspected we were low on the approach based on visual cues. The aircraft gave an ALTITUDE and PULL UP warning as we passed over a ridge. I elected to not respond to these warnings since I had visual on all terrain. We proceeded to runway 13R and made a normal landing. Once at the gate; we experimented with the CDU to see why this had happened. If we had selected the approach without the NEPOP transition; the approach would have loaded without the procedural hold as we intended to fly the approach. Since I selected the approach with the NEPOP transition we faced with the problem of the unwanted procedural hold a NEPOP. At the gate; we confirmed that NEPOP on Line 2 could not be line selected to Line 1. By line selecting URULO to Line 2 the proper sequence of waypoints were displayed. However; the altitude of 12;000 feet at NEPOP was dropped. It was possible to manually insert an altitude of 12;000 feet at NEPOP. Looking back with 20/20 hindsight; I now believe when URULO was line selected to line 2 we lost the altitude protection of 12;000 feet at NEPOP. Altitudes at each waypoint on a non-ILS approach must be checked after any and all waypoint modifications.


Second narrative: As a result of being unable to accept a left turn heading into a storm cell; we were assigned a late runway change from the planned landing runway of ILS 13L to RNAV 13R and a right turn. Shortly after this came the clearance to fly direct to NEPOP. As the PM I observed the Captain select the correct approach and NEPOP transition for the runway. The PF then made attempt to bring the NEPOP that had the correct constraint to the [Line] 1 position and was unable. At the [Line] 1 there was not a required constraint of 12000A. The [Line] 2 had a procedure hold with Constraint of 13000A and at [Line] 3 a NEPOP with the 12000A. By moving the FAF URULO fix at [Line] 4 up we were able to clear the hold but this action dropped out the 12000A constraint that was there. I did not catch this at the time as I was into a radio call shortly thereafter that cleared us to maintain 12000 and cleared for approach. We were now within 10nm of NEPOP and as we reset the MCP to min + with VNAV path in the FMA the aircraft left 12000 feet as we approached NEPOP. We broke out of the cloud bases at about 11800 and were in sight of the airport and terrain as we continued visually. As we crossed the NEPOP the controller asked us to confirm maintaining 12000. It was clear then that although we were in VNAV path we were had no constraint for NEPOP. I assured the controller that we did have the runway and terrain in sight. The descent path appeared to be clear of terrain and the course alignment was accurate and clear of clouds.In trying to debrief this event we found that by selecting the NEPOP transition we increased our workload. Had we simply selected the approach and executed; we would have gotten the constraints at [Line] 1. It seems natural to me to select the transition and I am not sure why deleting the hold became the problem. Asking for more time would have given us an opportunity to catch the disappearance of the constraints. We suggested that maybe not using VNAV procedures here may have been helpful; but that too is questionable. I for one would like to see a possible fix for the way the FMC displays the options. Is it not possible that the [Line] 1 fix has the same constraints as the [Line] 2 and not dashes?


Synopsis: Air carrier flight crew reported descending below charted altitude and receiving a GPWS terrain warning on approach to SKBO; following a late runway change. Crew had some difficulty with FMS programming that was cited as a contributing factor.