When GPS Fails: Lessons from a Fatal Air Ambulance Crash in New Mexico

When GPS Fails: Lessons from a Fatal Air Ambulance Crash in New Mexico

Losing situational awareness during any flight is dangerous. In Instrument Meteorological Conditions (IMC), it can be fatal.

When clouds or darkness obscure the horizon, pilots can find themselves in an extremely perilous situation. This is precisely why instrument flight training requires students to practice "partial panel" flying — where instructors cover instruments such as the attitude indicator to simulate equipment failures.

Students are trained to handle that scenario. Yet, according to practitioners in the field, one situation is chronically undertrained: the failure of RAIM — Remote Autonomous Integrity Monitoring. RAIM's job is to tell the pilot whether GPS information is reliable. Losing RAIM during an approach is like a phone call dropping without you noticing — by the time you realize it, you've already missed critical information.

RAIM: A Preflight Essential

RAIM is one of the items pilots must verify before departure. For example, if you anticipate a 23-minute flight to your destination followed by a GPS approach, you should enter the estimated time of arrival into the GPS system to confirm RAIM will be available. Even when it is predicted to be available, pilots should always plan an alternate approach — such as a VOR or ILS/LOC — as a backup.

Once RAIM is lost, GPS accuracy can no longer be guaranteed, and the pilot may effectively be flying blind. The FAA and flight instructors recommend that if RAIM is lost en route, pilots should immediately switch to another approved navigation method — such as requesting radar vectors or transitioning to VOR navigation. If an approach has not yet commenced, notify ATC promptly and be prepared to execute a missed approach.

NTSB Preliminary Report: New Mexico Air Ambulance Crash

The National Transportation Safety Board (NTSB) recently released a preliminary investigation report on a pre-dawn air ambulance crash that occurred in New Mexico on May 14, 2024. The accident claimed the lives of four people: two pilots and two flight nurses.

According to the NTSB report, a King Air 90 en route to Sierra Blanca Regional Airport (KSRR) near Ruidoso, New Mexico, experienced repeated GPS outages caused by military jamming operations. The flight path traversed mountainous terrain and a Military Operations Area (MOA).

At the time of the accident, NOTAMs were in effect advising pilots that KSRR's Automated Weather Observing System (AWOS) was out of service, and that military GPS jamming would be active. This information was reportedly available to the crew via ForeFlight preflight briefing and the NOTAM system.

Sequence of Events

The accident aircraft was based at Roswell Air Center (KROW, elevation 3,671 ft) in New Mexico and operated by Generations Jets, which employed both pilots. The two flight nurses were employed by Trans Aero MedEvac.

The mission was to fly approximately 51 nautical miles to KSRR (elevation 6,813 ft) to pick up a patient and transport them to Albuquerque. The NTSB report noted that while visibility that night was VMC, there was no moonlight — a "dark night" environment.

KSSR has two instrument approach procedures: an ILS/LOC and an RNAV (GPS) approach to Runway 24. The approach procedures include a note explicitly stating: "NA when local altimeter setting not received."

The accident aircraft was equipped with a Spidertracks flight tracking device, which recorded GPS altitude, heading, airspeed, and position. The NTSB reconstructed the flight using Spidertracks data combined with ADS-B data, noting discrepancies between the two: Spidertracks GPS altitudes were generally approximately 600 feet higher than ADS-B altitudes, and ADS-B data contained significant gaps.

Reconstructed Timeline:

• 11:52 PM MDT, May 13: The aircraft departed KROW on an IFR flight plan. The crew contacted Albuquerque ARTCC for an IFR clearance and was cleared as filed to KSRR at 12,000 ft MSL.

• Shortly after midnight: ATC advised the crew they were 1,000 feet high. The crew acknowledged and stated they were correcting, then reported loss of GPS capability and requested heading guidance. ATC issued a heading of 275 degrees toward KSRR and asked what approach type was needed. The crew requested the RNAV approach to Runway 24.

• 12:01 AM: The ATC supervisor contacted the military requesting that GPS jamming be halted, and cleared the aircraft to REYOK, the initial approach fix approximately 21.1 nm from the airport. The crew read back the clearance and turned northbound. Minutes later, they reported loss of GPS navigation and requested the ILS approach instead. The report notes that three other aircraft that night also reported GPS failures; one required additional assistance because the crew could not identify the ground-based navaid.

• 12:04 AM: ATC advised the crew it would provide radar vectors in "a few minutes" to position them for a straight-in approach to REYOK.

• 12:05 AM: The ATC supervisor again contacted the military requesting jamming cessation. 12:07:34 AM: ADS-B data resumed.

• 12:08:06 AM: The aircraft was approximately 31 nm northeast of KSRR, tracking northwest. The crew reported the airport in sight, though the transmission was stepped on by other radio traffic. The crew called again, stating they would "go visual."

• ATC cleared the aircraft for a visual approach and advised that IFR cancellation could be made at or above 9,000 ft MSL or on the ground via a Flight Service Station. The crew confirmed the clearance and stated they would cancel IFR "in a few minutes." No further transmissions were received from the crew.

Between the aircraft and the airport stood the Capitan Mountains, with terrain reaching 10,201 ft MSL.

• 12:10 AM: The ATC supervisor notified the military that the aircraft was executing a visual approach. Military GPS jamming operations resumed.

• 12:10:27 AM: ADS-B data reappeared. The aircraft began descending toward the airport with a slight right turn. Spidertracks recorded an altitude of 9,820 ft, then a descent to 9,400 ft, followed by a climb.

• 12:15:26 AM: The final Spidertracks data point recorded GPS altitude 9,823 ft, heading 250 degrees, groundspeed 150 knots.

The aircraft subsequently struck terrain at approximately 9,950 ft MSL — 730 feet east and 230 feet below a radio facility atop the Capitan Mountains at approximately 10,180 ft MSL. The impact triggered a fire that grew into a wildfire.

Warnings for Pilots

The NTSB emphasized that the above constitutes a preliminary report and remains subject to revision. The final report is expected to take 18 to 24 months to complete.

Nevertheless, the accident has sparked widespread discussion in the flight training community. Every tragedy offers other pilots an opportunity to learn.

This case also prompts deep reflection on aeronautical decision-making: if you were the pilot-in-command and lost GPS during an approach, what would you do?

A veteran flight instructor once warned: "GPS is a wonderful navigation tool — right up until the moment it isn't." He required his students to be proficient on all navigation systems and all published approach types: ILS/LOC, VOR, NDB, SDF, LDA, and RNAV — and to operate them under both full-panel and partial-panel conditions.

His words remain as relevant as ever: If you lose RAIM on an approach, climb immediately. Losing situational awareness in IMC or at night can mean flying into cumulo granite — a mountain wall. Near an airport, it may mean striking an antenna or a structure. If GPS fails, do not hesitate — climb immediately.

The statistics bear this out: the odds of striking an obstacle in the air are almost always far lower than when hugging the terrain below.

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