History of Flight
On August 16, 2015, about 1103 Pacific daylight time, a Cessna 172M (N1285U) and an experimental North American Rockwell NA265-60SC Sabreliner (N442RM, call sign Eagle1) collided in midair about 1 mile northeast of Brown Field Municipal Airport (SDM), San Diego, California. The pilot and sole occupant of N1285U and the two pilots and two mission specialists aboard Eagle1 died; both airplanes were destroyed.
N1285U was registered to a private individual and operated by Plus One Flyers under 14 CFR Part 91 as a personal flight. Eagle1 was registered to and operated by BAE Systems Technology Solutions & Services, Inc., for the US Department of Defense as a public aircraft supporting the US Navy. No flight plan was filed for N1285U, which originated from Montgomery-Gibbs Executive Airport. A mission flight plan was filed for Eagle1, which originated from SDM about 0830 and was returning. Visual meteorological conditions prevailed.
At the time of the accident, the SDM tower had combined positions to local control, staffed by a qualified local controller (LC) conducting on-the-job training with a developmental controller (LC trainee) on local control. The LC trainee transmitted instructions while the qualified LC monitored.
According to ATC data, the pilot of N1285U contacted the tower at 1049:44, requesting touch-and-go maneuvers in the VFR traffic pattern. N1285U was inbound about 6 miles northeast, at 2,600 ft indicated altitude. Other aircraft included a Cessna 172 (N6ZP), a helicopter (N8360R), and a Cessna 206 (N5058U).
Between 1049 and 1054, traffic was active. At 1052:57, the LC trainee cleared N1285U for a touch-and-go on runway 26R. At 1054:46, on final approach, the pilot of N1285U announced a go-around and was instructed to follow N6ZP on the right downwind. At 1056:31, the LC trainee advised N1285U to expect runway 26L next.
By 1057:27, N1285U was cleared for a touch-and-go on runway 26L, which was acknowledged. After the touch-and-go, N1285U turned right, crossing the departure corridor of runway 26R, to enter a right downwind for runway 26R.
At 1059:04, Eagle1, 9 miles west, contacted the tower requesting full-stop landing. The LC trainee instructed Eagle1 to enter a right downwind for runway 26R at or above 2,000 ft msl.
At 1059:31, the LC trainee acknowledged N5058U's hold short of runway 26L. This was his last transmission. At 1059:33, the qualified LC terminated training and took over due to increased traffic, controlling nine aircraft thereafter.
The LC made several errors. At 1059:44, N6ZP requested departure; the LC did not respond immediately. At 1100:23, he mistakenly cleared N5058U for takeoff on runway 26R instead of 26L, correcting after the pilot questioned. At 1100:36, he instructed the helicopter, then corrected. At 1101:15, Eagle1's CVR recorded the copilot saying, "got one on the runway," and at 1101:19, the pilot commented, "wowww. he's like panicking."
At 1102:14, while on right downwind and overtaking N1285U from behind and left, Eagle1 reported traffic in sight left and right. Radar showed N6ZP left of Eagle1 and N1285U between Eagle1 and SDM on a closer right downwind.
At 1102:32, the LC instructed N6ZP (believing it was the Cessna on right downwind) to make a right 360° turn over the airport, despite N6ZP already departing. N6ZP acknowledged and turned. At 1102:42, the LC cleared Eagle1 to turn base and land on runway 26R. The LC later stated that after the clearance, he looked up and saw the Cessna on downwind (still thought to be N6ZP) continuing straight. At 1102:56, he queried N6ZP, who said he was turning. At 1102:59, Eagle1's pilot said, "I see the shadow but I don't see him."
At 1103:04, the LC transmitted to N1285U for the first time in nearly 6 minutes. The pilot acknowledged at 1103:07. At 1103:08, the LC asked if N1285U was still on the right downwind. No response. The LC and trainee then witnessed the collision.
Witnesses saw both airplanes eastbound north of SDM, then an explosion and fragments. Another witness saw intersecting flightpaths with no corrective action; the smaller airplane broke apart, the larger lost a wing and nosed down.
Personnel Information
N1285U Pilot: Age 60, private pilot certificate (single-engine land) since 1997. FAA third-class medical November 2014 with corrective lenses requirement. Logged about 277 total flight hours, 9.7 in last 6 months.
Eagle1 Pilot (pilot monitoring, left seat): Age 41, airline transport pilot certificate since 2011, flight instructor since 2008. First-class medical April 2015, no limitations. About 4,480 total hours; 18 hours in last 90 days, 4 in type. Most recent flight review April 2015.
Eagle1 Copilot (pilot flying, right seat): Age 66, airline transport pilot since 2005, flight instructor since 2009. First-class medical January 2015 with corrective lenses. About 7,150 total hours; most recent flight review April 2015.
Local Controller (LC): Age 59, certified professional controller and CIC. 37 years ATC experience. Qualified on all positions at SDM September 2014. On-the-job training instructor since February 2015. Most recent recurrent training July 2015. FAA second-class medical September 2014 with corrective lenses.
Local Control Trainee: Age 27, qualified on ground and flight data positions June 2015. Started local control OJT June 27, 2015. Most recent recurrent training July 2015. FAA second-class medical April 2015, no limitations.
Aircraft Information
N1285U: Cessna 172M, high-wing, four-seat, 1976. Equipped with Lycoming O-320-D2G engine (160 hp) under supplemental type certificate. Gross weight 2,300 lbs. Most recent annual inspection July 15, 2015; total time 9,848.1 hours. Equipped with rotating beacon, anticollision strobes, navigation lights, landing light, taxi light. Operational status at accident unknown. No TAS, TCAS, or ADS-B.
Eagle1: North American Rockwell NA265-60SC Sabreliner, low-wing, five-seat, 1974. Two Pratt and Whitney JT12A-8 turbojet engines (3,000 lbs thrust each). Experimental airworthiness certificate due to external test pod. Maximum gross weight 22,900 lbs. Most recent annual inspection July 20, 2015; total time 13,418 hours. Equipped with Fairchild GA-100 CVR (30-min loop). Anticollision lights, ice inspection lights, strobe/position lights, landing/taxi lights. Operational status unknown. No TAS, TCAS, or ADS-B.
Meteorological Information
At 1053, SDM automated weather: wind 310° at 6 knots, visibility 10 statute miles, clear skies, temperature 33°C, dew point 19°C, altimeter 29.87 inHg.
Airport Information
Brown Field Municipal Airport (SDM) is a general aviation airport in San Diego, California. The tower had combined positions during the accident.
Wreckage and Impact Information
The wreckage was located about 1.5 miles northeast of SDM in two primary debris fields.
N1285U: Debris field about 1,200 ft long on heading 055°, containing some Eagle1 fragments. Main wreckage included engine, propeller, partial cabin. Engine partially attached to firewall, left side impact damage. Propeller separated, heavily gouged, one blade aft bend. Left wing attached to cabin roof section with thermal damage; flap and aileron attached. Inboard leading edge impact damage with red transfer marks. Fuselage and right wing highly fragmented.
Eagle1: Most debris within 100 ft radius; no N1285U parts in that radius. Main wreckage on heading 060°, including cabin, left wing, empennage, both engines, test pod. Forward cabin crushed on upper left side. Left wing on trailing edge. Engines near tail with crush damage. Test pod had impact and thermal damage.
Eagle1 right wing found on a road near N1285U debris field, about 400 ft north of main wreckage. A power transmission line was separated. The wing displayed leading-edge damage from near tip to separation point. A 5-ft section of leading edge from stall fence inboard revealed internal surfaces. Lower surface had metallic impact marks and paint transfer.
Follow-up examination at a secure facility found impact marks on Eagle1 right wing consistent with N1285U's engine spacing.