Investigation Summary
The collision occurred at approximately 15,150 feet in VFR conditions. The F-4B, which was experiencing radio failure and a malfunctioning transponder, was performing a high-speed 'climb-and-descent' maneuver. The radio failure was critical as it prevented the F-4B crew from communicating with Los Angeles Center or receiving traffic advisories, leaving them isolated in one of the world's busiest air corridors. The DC-9 was climbing on a standard instrument departure. The aircraft had a closure rate of approximately 1,000 feet per second, leaving almost no time for visual acquisition. Due to this extreme speed and the 'blind spot' created by the F-4B's cockpit structure and the DC-9's window pillars, neither crew saw the other in time to react. The F-4B's vertical stabilizer sliced through the DC-9's fuselage just aft of the cockpit, causing the airliner to break up instantly.
Final Conclusions
The NTSB determined the probable cause was the failure of both crews to see and avoid each other. Contributing factors included the high closure rate, the failure of the F-4B to use its transponder in a high-traffic area, and the lack of radar separation provided by ATC to the DC-9 regarding the non-transponding military aircraft.
Video Analysis
The Collision Over Los Angeles | Hughes Airwest Flight 706 — A detailed look at the 1971 mid-air collision between a commercial DC-9 and a Marine Corps F-4 Phantom.
If playback is blocked, the owner has disabled embedding — use the link above.
Crew Experience
Captain
Captain Theodore Nicolay, aged 50, held airline transport pilot certificate No. 474317, with ratings in airplane multiengine land, F-27, DC-3, and DC-9.
First Officer
First Officer Price Bruner, aged 49, held airline transport pilot certificate No. 611777, with ratings in airplane multiengine land, F-27/227, DC-3, DC-9 and commercial privileges in airplane single-engine land.
Pilot
First Lieutenant James R. Phillips, aged 27, held commercial pilot certificate No. 1619834... He also had accumulated approximately 400 hours in civil aircraft.
Radar Intercept Officer
First Lieutenant Christopher E. Schiess, aged 24, joined the U. S. Marine Corps on November 7, 1969, and completed his RIO training January 3, 1971.
Systems & Failure Modes
Transponder
The F-4B's transponder was failed, preventing ATC from seeing the jet's altitude and identity.
See-and-Avoid
The primary visual separation method which failed due to high closure speeds and cockpit blind spots.
Secondary Surveillance Radar
The ATC system that relied on aircraft transponders to provide separation services.
Interesting Facts
- 01The F-4B was traveling at approximately 415 knots at the time of impact.
- 02The DC-9 was on an IFR flight plan, while the F-4B was flying under VFR.
- 03The F-4B's transponder was inoperative, making it invisible to secondary radar.
- 04The collision occurred in a 'see-and-avoid' environment despite the DC-9 being under radar control.
- 05The F-4B pilot was a decorated Vietnam veteran but was unfamiliar with the local civilian corridor.
- 06The DC-9 Cockpit Voice Recorder was recovered but provided no data as the tape was destroyed by post-impact fire due to a failure of its thermal protection.
- 07The F-4B was on a cross-country flight from NAS Fallon, Nevada, to MCAS El Toro, California.
Safety Actions & Advisories
TCAS Development
Source ↗The accident accelerated the development of the Traffic Collision Avoidance System (TCAS) to reduce reliance on visual 'see-and-avoid'.
Terminal Control Areas
Source ↗The FAA expanded the use of Terminal Control Areas (now Class B airspace) to strictly segregate VFR and IFR traffic in busy corridors.
Military Transponder Policy
Source ↗New regulations required military aircraft to operate transponders at all times when in civilian controlled airspace.
Location
APPROXIMATE AREA ONLY · This position predates coordinate provenance tracking. Treat it as an approximate marker for the area, not the accident site. No map is shown, because a marker here would imply a precision the record does not have.
Reported location: Duarte, California