Recommendations based on investigation into April 2017 Pilatus Accident.
The National Transportation Safety Board hopes the National Weather Service will create additional guidance for pilots about the hazards surrounding non-convective turbulence conditions, as well as provide additional formal training to NWS forecasters to encourage consistency of analysis, interpretation and forecasting of low-level turbulence.
The NTSB’s recommendations evolved from an on-going investigation into the April 2017 crash of a Pilatus PC-12 shortly after takeoff from Rick Husband Amarillo International Airport (AMA) in Texas. The aircraft departed AMA about 2348 local time as a Part 135 air ambulance flight on an IFR flight plan. The accident claimed the lives of the pilot and two additional crewmembers. The Board said the pilot reported level at 6,000 Msl about three minutes after takeoff but disappeared from radar a minute later. Witnesses reported a fireball south of the airport.
The NTSB investigation showed that low-level turbulence may have been present over Amarillo below 8,000 ft on the night of the accident, weather that may not have been passed on to the Pilatus pilot. While the NWS Aviation Weather Center issued several weather advisories around the time of the accident for areas near the accident location, there were no airmen’s meteorological information (advisories active for turbulence below 10,000 ft) at the accident location at the accident time of the crash.
During a visit to the NWS AWC a few months after the accident, NTSB investigators learned that different forecasters may have different professional criteria for the issuance of local turbulence advisories like AIRMETS, when convective SIGMETS already exist in the same area. The Board believes low-level turbulence is also not adequately covered in formal training for AWC and other NWS forecasters.
Although the cause of the Texas accident has not yet been determined, the NTSB said the safety risks associated with low-level turbulence are well known and that there should be consistency in the issuance of turbulence weather advisories for pilots no matter what altitude that might be operating.