Sierra West Airlines Flight 887

NTSB narrative

The captain and first officer were assigned a two-leg overnight on-demand cargo flight. The flight crew were accustomed to flying night cargo flights, had regularly flown together, and were experienced pilots. The first leg of the trip was uneventful and was flown by the captain; however, their trip was delayed 2 hours and 20 minutes at the intermediate stop due to a delay in the freight arriving. The flight subsequently departed with the first officer as the pilot flying. While enroute, about forty minutes from the destination, the flight crew asked the air traffic controller about the NOTAMs for the instrument landing system (ILS) instrument approach procedure at the destination. The controller informed the flight crew of two NOTAMs: the first pertained to the ILS glidepath being unserviceable and the second applied to the localizer being unserviceable. When the controller read the first NOTAM, he stated he did not know what “GP” meant, which was the abbreviation for the glideslope/glidepath on the approach. The controller also informed the flight crew that the localizer NOTAM was not in effect until later in the morning after their expected arrival, which was consistent with the published NOTAM. The flight crew subsequently requested the ILS approach and when the flight was about 15 miles from the final approach fix, the controller cleared the flight for the ILS or localizer approach, to which the captain read back that they were cleared for the ILS approach. As the flight neared the final approach fix, the captain reported that they had the airport in sight; he cancelled the instrument flight rules flight plan, and the flight continued flying towards the runway. The airplane crossed the final approach fix off course, high, and fast. The cockpit voice recorder (CVR) transcript revealed that the captain repeatedly instructed the first officer to correct for the approach path deviations. Furthermore, the majority of the approach was conducted with a flight-idle power setting and no standard altitude callouts were made during the final approach. Instead of performing a go-around and acknowledging the unstable approach conditions, the captain instructed the first officer to use the air brakes on final approach to reduce the altitude and airspeed. Shortly after this comment was made, the captain announced that they were low on the approach and a few seconds later the captain announced that trees were observed in their flight path. The CVR captured sounds consistent with power increasing; however, the audible stall warning tone was also heard. Subsequently, the airplane continued its descent and impacted terrain about .70 nautical mile from the runway. Airport surveillance video captured the final 2 minutes of flight. Although low clouds and visibility were reported in the area of the airport, it is unlikely that the airplane entered instrument meteorological conditions in the flight’s final 2 minutes given that the airplane’s landing light was continuously in view until the airplane’s impact with trees and terrain. Furthermore, the video revealed that about the time the air brake comment was made by the captain, the airplane’s descent rate was observed to increase. Examination of the airplane revealed no evidence of preimpact mechanical malfunctions or failures with the airplane or its engines. The air brakes and their actuators were found in an extended position, the landing gear were down, and the flaps were stated by the captain to be set to full. The airplane flight manual (AFM) prohibited the use of air brakes during the approach unless anti-ice was used; however, there was no indication that anti-ice was used. It is likely that after the captain instructed the first officer to use the air brakes, the flight entered a descent that could not be recovered from, despite the rapid increase in power in the final moments of the flight. The flight profile of idle power, air brakes deployed, landing gear down, and full flaps was not a configuration that the airplane manufacturer possessed data for given that it was not an AFM approved approach configuration. The captain advised the first officer to fly the ILS approach and to follow the glideslope, despite the glideslope being out of service per the NOTAM. It was not possible to determine whether the high and low comments from the flight crew were in reference to precision approach path indicator lights, cockpit instrumentation, or a visual glidepath assessment based upon the crew’s perception of the lighted but dark night runway environment. The glideslope portion of the ILS was not broadcasting a signal due to the equipment being removed for maintenance. The investigation was unable to determine what the glideslope indications displayed in the cockpit were due to impact-related damage to the instrumentation. The approach was being conducted during dark night conditions, which likely further exacerbated the flight crew’s inability to establish a proper glide path and see the approaching trees and terrain. The controller did not state that the glideslope was out of service when he cleared the airplane for the ILS localizer approach procedure, nor was there a requirement to do so when an ILS or localizer approach was to be flown. Furthermore, when the airplane was near the final approach fix, the captain reported that they had the airport in sight, and he cancelled the instrument flight rules flight plan. The decision by the flight crew to continue straight in to land, rather than flying the procedure turn, contributed to the airplane being high for the majority of the final approach. The CVR revealed that throughout the enroute descent and approach, the captain repeatedly instructed the first officer on how to fly the airplane, reprimanding and yelling at him about basic airmanship tasks such as heading and altitude control. The captain also took control of the airplane multiple times before the final approach. The captain had ample indications that the first officer was not performing adequately to continue the flight as the pilot flying. The captain could have demonstrated leadership and positive crew resource management by relieving the first officer of flying duties well before the final approach commenced, given the challenging nature of the dark night approach that was ahead. The operator reported the first officer had not received an upgrade to captain, even after multiple years of experience on the accident airplane, due to his lack of aeronautical decision making and airmanship necessary to become a captain. This assessment was consistent with his performance during the accident flight. Furthermore, the captain’s training record showed multiple deficiencies during training. Had the operator had a flight data monitoring program (FDM) and safety management system (SMS), they could have had additional methods of identifying and monitoring the poor performing flight crew and made proactive decisions, rather than waiting for an accident to occur to discover the flight crew’s procedural non-compliance. The National Transportation Safety Board has standing recommendations to Part 135 operators to implement SMS and FDM, and for the Federal Aviation Administration to require SMS and FDM in Part 135 operations. Both pilots had cardiovascular disease that placed them at increased risk of a sudden impairing or incapacitating medical event such as heart attack or abnormal heartbeat; however, based upon the totality of the investigation’s findings, it is unlikely that the captain’s or first officer’s cardiovascular disease contributed to the accident. Furthermore, the toxicology reports for the flight crew revealed no conditions or findings that would have contributed to the accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset