The NTSB released its preliminary report this week on a May 14 air ambulance accident near Lincoln, New Mexico. The Beech C90, operated by Generations Jets to pick up a patient for transport, was destroyed after impacting terrain during a Part 135 flight from Roswell to Ruidoso. Both pilots and two flight nurses were killed.
GPS Reports And Vectors
After departing Roswell about 11:52 p.m. on May 13, the crew contacted Albuquerque Center and requested an IFR clearance to Sierra Blanca. At 12:00 a.m., the controller advised the crew that the airplane was at 13,000 feet MSL, 1,000 feet above its assigned altitude, and the pilot replied that the airplane had lost GPS capability and needed a heading. Controllers then provided headings toward Sierra Blanca, while the crew changed its requested approach from the RNAV Runway 24 to the ILS after reporting the GPS problem.
About a minute after the GPS report, a controller contacted an operations supervisor and asked that the military stop conducting a nearby jamming operation. During the same portion of the flight, three other aircraft reported a loss of GPS, and one required additional help identifying a ground-based navigation aid.
Flight tracking data from Spidertracks and ADS-B generally aligned, though the NTSB said in the report that Spidertracks GPS altitudes were about 600 feet higher than ADS-B altitudes and ADS-B returns had large gaps.
Visual Approach
At about 12:08 a.m., while roughly 31 miles northeast of Sierra Blanca, the crew reported seeing Ruidoso and said they could proceed visually. Albuquerque Center cleared the flight to Sierra Blanca for a visual approach, and the crew responded that it would cancel IFR shortly.
No further radio calls were received from the airplane. Soon after, the aircraft turned southwest toward the airport, began descending and later climbed from about 9,400 feet to the final Spidertracks point at 9,823 feet GPS altitude. Wreckage was found at about 9,950 feet, about 730 feet east of the Capitan Mountains Summit Radio Facility. A post-impact fire started a forest fire.
NOTAMs And Airport Information
ForeFlight briefing materials reviewed by investigators included NOTAMs showing Sierra Blanca’s automated weather system was out of service and warning that GPS, including WAAS, GBAS and ADS-B, might not be available in the area during the accident flight. According to the NTSB, the briefing also showed no METAR or TAF for Sierra Blanca. Both published instrument approaches to Runway 24 include a note stating the procedures are not authorized when the local altimeter setting is not received.
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