NTSB Factual Report

HISTORY OF FLIGHT

***This report was modified on October 31, 2016. Please see the docket for this accident to view the original report.***

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 the provisions of 14 Code of Federal Regulations (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 in support of the US Navy. No flight plan was filed for N1285U, which originated from Montgomery-Gibbs Executive Airport, San Diego, California. A mission flight plan was filed for Eagle1, which originated from SDM about 0830 and was returning to SDM. Visual meteorological conditions prevailed at the time of the accident.

On the morning of the accident, the SDM airport traffic control tower (ATCT) had all control positions (local and ground control) in the tower combined to the local control position. The position was staffed by a qualified local controller (LC)/controller-in-charge (CIC) who was conducting on-the-job training with a developmental controller (LC trainee) on the local control position. The LC trainee was transmitting control instructions for all operations; however, the qualified LC was closely monitoring the LC trainee's actions and was responsible for all activity at that position.

According to air traffic control (ATC) radar and voice communications data, the pilot of N1285U contacted the SDM ATCT at 1049:44 and requested touch-and-go maneuvers in the visual flight rules (VFR) traffic pattern. N1285U was inbound about 6 miles to the northeast of SDM, at an indicated altitude of 2,600 ft. About that time, another Cessna 172 (N6ZP) and a helicopter (N8360R) were conducting operations in the VFR traffic pattern, and a Cessna 206 Stationair (N5058U) was inbound for landing after carrying parachutists to a local drop zone about 5 nautical miles (nm) east of the field.

Between about 1049 and 1054, N6ZP and the helicopter continued to conduct approaches, N5058U landed on runway 26L, a Skybolt (N81962) reported west of SDM for landing on runway 26L, and a Cessna Citation (XALVV) reported straight in for landing on runway 26R. At 1052:57, the LC trainee cleared the pilot of N1285U for a touch-and-go on runway 26R, which the pilot acknowledged. At 1054:46, when N1285U was on final approach of the first approach to runway 26R, the pilot advised the LC trainee that he was going to go around. The LC trainee acknowledged the transmission and instructed the pilot to follow "a Cessna" (N6ZP) on the right downwind.

At 1056:31, the LC trainee advised the pilot of N1285U to expect runway 26L on the next approach, which the pilot acknowledged. At that time, three aircraft were using runway 26R (Global Express [N18WZ] was inbound for landing, N6ZP was on a right base for a touch-and-go, and XALVV was on short final) and three aircraft were using runway 26L (N1285U was turning right downwind for the touch-and-go, N81962 was on a left downwind for landing, and N8360R was conducting a touch-and-go operation). Figure 1 shows the aircraft in the SDM traffic pattern about 8 minutes before the accident.

At 1057:22, the LC trainee cleared the pilot of N1285U for a touch-and-go on runway 26L, and at 1057:27, the pilot acknowledged the clearance. At 1058:22, the LC trainee cleared the pilot of N6ZP for a touch-and-go on runway 26L. At 1058:29, the pilot of N6ZP stated, "…ah two six right cleared touch and go." After the pilot of N1285U completed the touch-and-go on runway 26L, the pilot turned the airplane right, crossing through the departure corridor of runway 26R, and entered a right downwind for runway 26R.

At 1059:04, when Eagle1 was 9 miles west of SDM, the flight crew contacted the SDM ATCT and requested a full-stop landing. Throughout Eagle1's cockpit voice recorder (CVR) recording, the pilot, seated in the left seat, was communicating on the radio and responding to checklists, consistent with that pilot acting as the pilot monitoring and the copilot, seated in the right seat, acting as the pilot flying. The LC trainee instructed the Eagle1 flight crew to enter a right downwind for runway 26R at or above an altitude of 2,000 ft mean sea level (msl).

At 1059:18, the pilot of N5058U reported holding short of runway 26L on taxiway C. (N5058U had landed on runway 26L at 1052:30 and was returning to runway 26L for takeoff.) The LC trainee mistakenly advised the pilot of N5058U to hold short of runway 26R. The pilot of N5058U clarified that he was holding short of 26L, and, at 1059:31, the LC trainee acknowledged the transmission. That was the last transmission from the LC trainee. At 1059:33, the qualified LC terminated the LC trainee's training and took over control of communications due to increased traffic. The LC trainee signed off the position but remained in the tower to observe operations. From this time until the collision occurred (about 1103), the LC was controlling nine aircraft.

During the next 2 minutes, the LC made several errors that were either corrected by him or by the pilots under his control. At 1059:44, after the pilot of N6ZP completed a touch-and-go on runway 26R, he requested a right downwind departure from the area. The LC did not respond. At 1100:23, the LC instructed, "stationair five eight uniform two six right cleared for I'm sorry two six left cleared for takeoff." At 1100:29, the pilot of N5058U stated, "uh I'm sorry was that for five eight uniform?" The LC then cleared the pilot of N5058U for takeoff from runway 26L. At 1100:36, the LC transmitted, "helicopter six zero romeo there is a ces ah cen ah correction stationair just ahead they are going to the right runway base leg for two six left." At 1100:46, the pilot of N6ZP repeated his request for departure; the LC then approved N6ZP's departure request, and N6ZP departed the traffic pattern in a northeasterly direction. At 1100:53, the LC instructed the helicopter pilot, "helicopter six zero romeo listen up turn crosswind" before correcting the instruction 4 seconds later to "turn base." At 1101:15, the Eagle1 CVR recorded the copilot state, "got one on the runway," and at 1101:19, the Eagle1 CVR recorded the pilot comment, "wowww. he's like panicking" (with an emphasis on panicking). Figure 2 shows the aircraft in the SDM traffic pattern from about 1101 until the time of the accident.

At 1101:49, the Eagle1 CVR recorded one of the mission specialists seated outside the cockpit ask "see him right there?" At 1102:14, while on the right downwind leg (and, according to radar data, while overtaking N1285U from behind and to the left) and abeam the tower, the Eagle1 flight crew reported to the ATCT that they had traffic in sight to the left and the right of their position. Radar data indicated that N6ZP was to the left of Eagle1 and heading to the northeast, and N1285U was between Eagle1 and SDM, on a closer-in right downwind leg.

At 1102:32, the LC instructed the pilot of N6ZP, which he thought was the Cessna on right downwind, to make a right 360° turn over the airport and rejoin the downwind. Despite the fact that, at that time, N6ZP was 2.3 nm northeast of the airport and was departing the area, the pilot of N6ZP acknowledged the instruction and initiated a right turn. At the same time, Eagle1's CVR recorded the pilot asking, "you still got the guy on the right side?"

At 1102:42, the LC instructed the Eagle1 flight crew to turn base and cleared the flight to land on runway 26R. The LC stated in the postaccident interview that after he cleared the Eagle1 flight crew to land, he looked up to ensure that Eagle1 was turning base and noticed that the Cessna on downwind (which he still thought was N6ZP) was continuing on its downwind track and had not begun the turn that he had issued. At 1102:56, the LC contacted the pilot of N6ZP, and the N6ZP pilot replied by stating that he was turning. At 1102:59, Eagle1's CVR recorded the pilot comment "I see the shadow but I don't see him."

At 1103:04, the LC transmitted "November eight five uniform"; this was the first ATC transmission with N1285U in almost 6 minutes and the first communication between the LC and N1285U. At 1103:07, the pilot of N1285U acknowledged the transmission, "eight five uniform." At 1103:08, the LC asked the pilot of N1285U if he was still on the right downwind leg. The pilot of N1285U did not respond. The LC and the LC trainee then witnessed Eagle1 and N1285U collide.

Two witnesses located on the ramp at SDM saw the two airplanes flying eastbound, to the north of SDM. The witnesses turned away momentarily, and as they turned back, they saw an explosion, followed by airplane fragments falling to the ground. Another witness located about 2 miles east-northeast of SDM saw both airplanes at the same altitude, on intersecting flightpaths. That witness reported that the smaller airplane was flying away from the airport and that the larger airplane was flying toward the airport and descending. He noted that neither airplane appeared to make any corrective action before the collision and stated that after the collision, the smaller airplane broke apart, while the larger airplane lost a wing, nosed down, and impacted the ground.

The LC stated in a postaccident interview that the traffic level was "light and not complex" at the beginning of the training session. He stated that he noticed the traffic volume and complexity became "moderate" when the LC trainee was under instruction, which prompted the LC to terminate training and take over communications. He reported that, at that time, he had four issues to resolve, one of which was the potential conflict between Eagle1 and the Cessna on the right. He indicated that he saw Eagle1 on a midfield right downwind leg when the pilot of Eagle1 reported that he was "abeam and had the traffic to the left and right in sight." The LC stated that, at that time, Eagle1 was flanked by two Cessnas. Although the Cessna on the right of Eagle1 was N1285U, the LC believed that the Cessna on the close-in right downwind was N6ZP; therefore, he instructed the pilot of N6ZP to make a right 360° turn to rejoin the midfield downwind. He stated that he felt the turn would resolve the conflict with Eagle1 and that the right turn would help the Cessna avoid Eagle1's wake turbulence. When the pilot of N6ZP acknowledged the turn, the LC believed that the pilot of the Cessna to the right of Eagle1 had received the instructions and that the potential conflict with Eagle1 would be resolved. The LC then instructed Eagle1 to turn base and cleared the flight crew to land on runway 26R.

The LC stated that after he cleared the Eagle1 flight crew to land, he looked up to ensure that Eagle1 was turning as instructed. When the LC noticed that the Cessna to the right of Eagle1 had not started the right 360° turn, he began to query the pilot of N6ZP and then the pilot of N1285U. At that point, he witnessed the collision.

The LC also indicated in the postaccident interview that controllers have personal limits about how many airplanes they could handle and that he could handle four aircraft on runway 26R and three aircraft on runway 26L. When the LC was asked what caused him to realize that the Cessna was N1285U and not N6ZP, he said it dawned on him that he had a right downwind departure, and through the process of elimination, it could not have been anyone else. The LC trainee stated in a postaccident interview that when the Cessna on the right did not start the right turn, he suggested to the LC that the intended aircraft may have been N1285U. The LC indicated that, in retrospect, he should have issued a traffic alert; however, the moment he realized that Eagle1 was turning into N1285U, it was too late to help. Figure 3 shows the calculated flight tracks of Eagle1 and N1285U. Figure 4 shows the aircraft under SDM ATCT control from 1049 until the time of the collision.

PERSONNEL INFORMATION

N1285U Pilot

The pilot, age 60, held a private pilot certificate for airplane single-engine land issued on December 2, 1997. His most recent Federal Aviation Administration (FAA) third-class medical certificate was issued on November 20, 2014, with limitations stating that he must wear corrective lenses for near and distant vision. The pilot's logbooks revealed that he had accumulated about 277 total flight hours, including 9.7 hours in the last 6 months.

Eagle1 Pilot (Pilot Monitoring)

The pilot, age 41, held an airline transport pilot certificate issued on April 1, 2011, and a flight instructor certificate issued on November 8, 2008 (most recent renewal on November 25, 2014). He held instructor ratings for airplane multiengine, single-engine, single-engine instrument, and glider. His most recent FAA first-class medical certificate was issued on April 30, 2015, with no limitations. According to BAE, the pilot had about 4,480 total flight hours. In the 90 days before the accident, he logged 18 hours in airplanes, including 4 hours in the accident airplane make and model. His most recent flight review was completed on April 13, 2015. The pilot was seated in the left seat and was acting as the pilot monitoring.

Eagle1 Copilot (Pilot Flying)

The copilot, age 66, held an airline transport pilot certificate issued on March 8, 2005, and a flight instructor certificate issued on October 20, 2009. The copilot held ratings for airplane multiengine and single-engine land. His most recent FAA first-class medical certificate was issued on January 12, 2015, with the limitation that he must wear corrective lenses. According to BAE, the copilot had about 7,150 total flight hours, and his most recent flight review was completed on April 13, 2015. The copilot was seated in the right seat and was acting as the pilot flying.

Local Controller/Controller-in-Charge

The local controller at the time of the accident, age 59, was a certified professional controller and CIC. He had 37 years of ATC experience: 5 years in the US Air Force, 24 years with the FAA, and 8 years with his current employer. He was qualified on all positions in the SDM ATCT on September 18, 2014, and was certified as an SDM CIC on September 19, 2014. He was designated as an on-the-job training instructor on February 10, 2015. His most recent recurrent training was completed on July 31, 2015, and included, but was not limited to, the topics of runway separation, visual separation, limited aviation weather reporting station (LAWRS), and opposite direction operations. His most recent FAA second-class medical certificate was issued on September 23, 2014, with the limitation that he must wear corrective lenses. He indicated in a postaccident interview that he was in compliance with the limitation at the time of the accident.

Local Control Trainee

The LC trainee, age 27, was qualified on ground and flight data control positions on June 25, 2015. He completed local controller classroom training on June 22, 2015, and started on-the-job training on the local control position on June 27, 2015. His most recent recurrent training was completed on July 31, 2015, and included, but was not limited to, the topics of runway separation, visual separation, LAWRS, and opposite direction operations. His most recent FAA second-class medical certificate was issued on April 28, 2015, with no limitations.

AIRCRAFT INFORMATION

N1285U Airplane

The white- and yellow-colored Cessna 172M was a high-wing, four-seat airplane manufactured in 1976 and powered by a Lycoming O-320-D2G engine rated at 160 horsepower, installed under RAM Aircraft Modifications supplemental type certificate SA2375SW. The airplane had a gross weight of 2,300 lbs. The most recent annual inspection was conducted on July 15, 2015. At the time of inspection, the airplane had a total ti

NTSB Probable Cause

The local controller's (LC) failure to properly identify the aircraft in the pattern and to ensure control instructions provided to the intended Cessna on downwind were being performed before turning Eagle1 into its path for landing. Contributing to the LC's actions was his incomplete situational awareness when he took over communications from the LC trainee due to the high workload at the time of the accident. Contributing to the accident were the inherent limitations of the see-and-avoid concept, resulting in the inability of the pilots involved to take evasive action in time to avert the collision.