MILITARY

On April 13, 2011, at 1222 Central daylight time, an air traffic control operational error and near midair collision occurred at the Midland International Airport (MAF), Midland, Texas, when TONE97 flight, consisting of two T-1 Jayhawk U.S. Air Force training aircraft (civilian-type Beech BE40 turbojets), lost separation with N631ME, a Raytheon-Beech King Air 300, on final approach to runway 28 at MAF. There were no injuries reported, and no damage to any of the involved aircraft.

MAF is a civil airport that is heavily used for training by Air Force aircraft based at Laughlin Air Force Base, located about 170 miles southeast of MAF. During the period surrounding the operational error, there were several different USAF flights operating in the MAF traffic pattern. TONE97 was a flight of two T-1 Jayhawks that entered the airport area on a left downwind approach to runway 28. Initial contact with the radar approach controller was routine, and at 1211:50, the approach controller advised the local controller that TONE97 was two aircraft. At 1217:35, TONE97 was switched to tower frequency and performed a communications check to ensure that the flight wingman was also on tower frequency. After completing the check, TONE97 contacted local control at 1218:02, reporting, “…5 mile initial.” The controller responded, “…left break midfield, descent in the break approved, runway 28 cleared for the option, traffic is a company Beech about three mile final full stop.” TONE97 acknowledged the clearance. At 1219:19, the pilot of N631ME checked in on tower frequency reporting on a visual approach to runway 28. At the time of the report, N631ME was on a wide right downwind about 7 miles north of the runway. The controller acknowledged the call and instructed the pilot to, “…continue for the runway.”

According to recorded radar data, TONE97 commenced the left break maneuver at 1220. As part of the break procedure, the wingman (TONE97-2) dropped back to a position about 1.4 miles behind the lead aircraft. Both aircraft entered close-in left downwind for runway 28. TONE97's transponder was on and the aircraft was displayed as a beacon target. TONE97-2’s transponder was off, so the aircraft produced only a primary radar target with no altitude reporting information available. According to the local controller, N631ME and both aircraft in TONE97 flight were visible from the tower.

At 1221:13, the local controller transmitted, "King Air 1ME you'll be number 3 for the field following a flight of two Beechjets currently about a mile on the left base, report the traffic in sight." The pilot replied, "...uh – I’ve got one of them in sight." The controller continued, "There’s one behind him a little bit higher just south of runway 34R." The pilot did not acknowledge the second transmission, and the controller responded to an unrelated coordination call from the approach controller. Recorded radar data showed that TONE97-2 and N631ME were converging on opposite base legs about 1.5 miles from runway 28. At 1221:53, the local controller instructed N631ME to, "...fly a little bit south and uh do you have the second aircraft in sight?" The pilot responded, "King Air 631ME's waving off, this is entirely ridiculous. We’re going to do a 360 if that’ll work for you." The controller instructed the pilot to make a right 360 and rejoin the final.

At 1223:09, an unidentified voice similar to that of N631ME transmitted, "...that was a perfect recipe for a midair." Following the incident, both aircraft in TONE97 flight and N631ME all landed safely on runway 28.

Radar Data

According to recorded radar data, the closest point of approach between TONE97-2 and N631ME was about 0.3nm. Graphics showing the flight tracks of the aircraft involved in this incident have been entered into the docket.

Personnel Interviews

MAF Local Control Trainee

At the time of the incident, training was in progress at the MAF Local Control (LC) position. The LC trainee had been previously certified at Kansas City Downtown tower in 2008, and transferred to MAF in May 2010. He was certified on the flight data, ground control, and clearance delivery positions. His work schedule included two night shifts and three day shifts. He described traffic at Midland as changeable from day to day, and noted that occasionally the peak traffic can move from the day shift to the night shift. It is very dependent on the military flight schedule.

The LC trainee had completed over 90 hours of training on the LC position. He had not yet received any instruction on the approach radar positions, but stated that he did try to obtain observation time in the radar room to familiarize himself with what the radar controllers do and how they sequence aircraft to the airport. Observation time was not documented on any training forms, as the activity was voluntary and not part of his formal training program.

The LC trainee described his training session as, "going fine, with light traffic." He recalled a pair of T-1 aircraft entering the pattern on an overhead approach. He stated that he instructed the pilots to break midfield, but the flight actually conducted their break further toward the departure end of the runway. As the two aircraft completed their overhead approach, the LC trainee stated that he advised the pilot of N631ME about them. The pilot responded that he had one of the aircraft in sight, but did not see the other. When the first T-1 was arriving at the runway 28 threshold, the second T-1 was on the left base. the LC trainee said that he instructed the pilot of N631ME to fly southbound if he did not have the second T-1 in sight, but it was too late because N631ME had already turned final. The LC trainee stated that his instructor on the position was standing right next to him, but did not intervene or provide any advice.

The LC trainee stated that his objective when sequencing arrivals conducting overhead approaches was to do the sequencing as early as possible. The radar controllers were expected to sequence aircraft to the runways, but the local controller was responsible for sequencing pattern traffic. He stated that he instructed the T-1 pilots to break midfield, and continued that if the pilots had actually executed the break at midfield, "...it would have worked out."

The LC trainee stated that he responded to the initial call from N631ME with an instruction to "continue" instead of advising the pilot that he was number three behind traffic because he was having a hard time breaking the habit he developed at the Kansas City tower, which has only class D airspace, of waiting to sequence aircraft until they are close in to the airport. His trainers at MAF were trying to get him to complete his sequencing earlier. The LC trainee noted that operations in class C airspace such as that surrounding MAF were different from operations in class D airspace, and that controllers had more separation responsibilities.

The LC trainee had used a STARS tower radar display at MKC, where the tower radar display was typically set to a range of approximately 12 to 13 miles. At Midland, the tower radar display range was typically set at 20 or more miles. That range setting was required by the local standard operating procedures manual. He stated that he had been told by his trainers that at MAF the radar range was set to a higher value in order to assist in sequencing traffic. Aircraft at Midland include military and air carrier jets that move faster than the traffic operating at MKC. The LC trainee stated that the approach controller’s planned sequence was normally clear from looking at the tower radar display, but if training was in progress in the radar room it was sometimes harder to tell what the plan was.

The LC trainee was shown a radar replay of the incident in order to refresh his memory of the event. He stated that as the King Air and the T-1 converged, he was looking at the two aircraft out the window and noted that the T-1 was higher than the King Air. He did not expect the King Air to turn inbound toward the airport without having seen the second T-1. When he and his instructor saw both aircraft turning onto the final approach course, their intent was to break one of the aircraft out to resequence it. When they discussed the incident later, the trainee said that the instructor's plan was to turn the T-1 out, while his own plan was to turn the King Air. Before they had a chance to act, the King Air pilot reported that he was going to make a 360 degree turn for spacing.

The LC trainee stated that when applying tower visual separation he was required to have both aircraft in sight and to resolve conflicts by issuing control instructions.

The LC trainee stated that using low approaches as a mechanism for resolving poorly executed sequencing situations was not a technique he had been taught or used. Though he had not yet begun radar training, he did have to complete a radar qualification test to work in the tower. He stated that when adjusting the sequence of inbound aircraft, he was only required to coordinate with the approach controller if his actions would change the sequence. Minor spacing adjustments did not need to be coordinated.

After the incident occurred,he was not involved in any debriefings or other discussions about it except between himself and his trainer. Their conclusion was that "assumption bit us" in that they did not expect the King Air pilot to turn toward the runway on his own.

Local Control Instructor

The LC instructor began working for the FAA in 1988 and transferred to Midland in August 1991. His schedule included Fridays and Saturdays off, but he typically worked every Friday on overtime. He had been working six day weeks for approximately the last two years. He said that it was difficult to get time off except for occasional hour or two at the end of a shift. Taking an entire day off on leave wa...