Investigation Summary
SkyWest Flight 1834 was executing a visual approach to Runway 34L at Salt Lake City International Airport. Simultaneously, a Mooney M20C, piloted by an instructor and a student, departed the nearby Salt Lake City Municipal 2 Airport after performing touch-and-go landings. The Mooney entered the restricted ARSA airspace without communicating with Air Traffic Control. Because the Mooney lacked a Mode-C transponder, its radar return appeared only as a primary target without altitude information. The TRACON controller was preoccupied with coordinating separation for a Boeing 737 and did not notice the Mooney's target, which was also briefly obscured by the data block of another aircraft. The SkyWest crew, following controller instructions to look for other traffic, never saw the Mooney until moments before impact. The two aircraft collided at approximately 7,000 feet MSL, causing both to break up in flight and crash into a suburban neighborhood.
Final Conclusions
The NTSB determined the probable cause was the Mooney instructor pilot's lack of navigational vigilance, leading to the unauthorized intrusion into the Salt Lake City ARSA. Contributing factors included the Mooney's lack of a Mode-C transponder and the failure of the SkyWest crew to see and avoid the Mooney. Member John K. Lauber filed a concurring statement dissenting from the inclusion of 'see and avoid' as a contributing factor, arguing that human physiological limitations and the crew's focus on other traffic assigned by ATC made detection unlikely. A subsequent civil court ruling in 1990 assigned 51% of the liability to the FAA controllers and 49% to the Mooney pilots.
Video Analysis
Looking back to 1987, and Utah's tragic mid-air collision — A retrospective on the January 15, 1987, mid-air collision between SkyWest Flight 1834 and a Mooney M20 over Kearns, Utah.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
SkyWest Airlines 1834 — Fairchild Swearingen SA-226TC Metro II · N163SW
Crew Experience
Captain
Michael Gambill
First Officer
Walter Ray
Systems & Failure Modes
Mode-C Transponder
A device that transmits an aircraft's altitude to ATC radar. The Mooney lacked this, meaning the controller could only see its position, not its altitude.
ARTS III Radar System
The automated radar terminal system used by controllers; it superimposed alphanumeric data blocks over primary radar returns.
See and Avoid
The primary regulatory method for avoiding collisions in visual weather, which the NTSB noted has significant human physiological limitations.
Interesting Facts
- 01The collision occurred at approximately 7,000 feet MSL in visual meteorological conditions.
- 02The Mooney M20C was not equipped with a Mode-C (altitude reporting) transponder.
- 03The Mooney's radar target was obscured by another aircraft's data block for 38 seconds, but was visible for 48 seconds immediately prior to the crash.
- 04Wreckage was scattered over a two-square-mile residential area in Kearns, Utah.
- 05Neither aircraft was equipped with, nor required to have, a Cockpit Voice Recorder (CVR) or Flight Data Recorder (FDR).
Safety Actions & Advisories
Mode-C Requirements
The NTSB reiterated recommendations for Mode-C altitude reporting equipment for all aircraft operating near airports served by TCAs and ARSAs.
TCAS Development
The accident accelerated the push for airborne collision avoidance systems (TCAS) to provide automated redundancy to the 'see and avoid' concept.
Controller Training
The NTSB recommended that FAA controller training include scenarios involving non-Mode-C intruders to prevent controllers from overlooking primary-only radar targets.
Known Controversies & Unanswered Questions
Liability Apportionment
Reference ↗While the NTSB primarily blamed the Mooney pilot, a U.S. District Judge later ruled that FAA controllers were 51% responsible for the crash due to their failure to utilize available radar information.