WPCNR AVIATION AGE. Special to WPCNR By Peter Katz, Publisher of the monthly aviation safety magazine NTSB REPORTER and columnist for Plane & Pilot Magazine, January 30, 2015:
Recent media reports would have you believe that a JetBlue Airbus A320L airliner came perilously close to being knocked out of the sky in a mid-air collision while on approach to Westchester County Airport.
That’s not quite what happened, although there was an incident which is being investigated by the Federal Aviation Administration. This article is based, in part, on what I learned from listening to a recording of communications between the two pilot flightcrew of Flight 94 and FAA Air Traffic Control.
JetBlue Flight 94 was en route from Orlando International Airport in Florida to Westchester County Airport on Sunday, January 25, 2014. The twin-engine Airbus A320L had made a number of step-down descents as it got closer to its destination.
It had been routed over Long Island, then Long Island Sound, and was getting ready for a left turn to follow the Connecticut shoreline towards Westchester.
According to a recording of radio communications between the flight and a New York Approach air traffic controller, at 1:44:18 (hour, minutes, seconds in Eastern Standard Time), the controller radioed, “JetBlue 94, you with me?” At 1:44:29, the flight radioed, “JetBlue 94, [descending out of] 5-point-6 [5,600 feet] for four [thousand feet] [with airport information] Zulu.”
At 1:44:56, the controller instructed the flight to “turn left heading 220 [degrees] join the shoreline Westbound.” The flight acknowledged the instruction, and at 1:345:31 the controller told the flight to “keep your speed up.”
At 1:46:00, the controller radioed, “JetBlue 94 descend and maintain 3,000 [feet],” followed at 1:47:16 by, “…you can reduce speed now to 180 [knots] and fly heading 220 short vector for sequence.” The instruction was acknowledged.
Although it was a windy day, the visibility was good and there were numerous aircraft operating in the Westchester area, some in contact with air traffic control and others being operated under visual flight rules (VFR).
Radar and radio contact with air traffic control is required to operate within 5 miles of the Westchester Airport and throughout most of the New York City area, including when above 3,000 feet West, South and immediately East of the 5 mile restriction around Westchester.
Pilots flying VFR outside of that airspace do not have to be in contact with air traffic control, but their aircraft must have an operating transponder when within 30 miles of the New York City airspace so that they can be easily detected on radar.
At 1:48:01, the controller radioed Flight 94, “VFR traffic 11 o’clock 2 miles moving northbound. Indicating 2,900 [feet]. Type is unknown.” The flight responded, “Yeah, we’re looking – JetBlue 94.”
The controller then added, “JetBlue 94, if you like you can climb or descend.” At 1:48:12, JetBlue 94 radioed, “we got ’em in sight, JetBlue 94.” The controller responded for the flight to maintain visual contact and separation.
Less than a minute later, at 1:49:11, the flight radioed, “Ah tower, JetBlue 94 we had to respond to a RA [resolution advisory] and we do have the airport in sight.”
An “RA” [resolution advisory] is a computer-generated instruction from the traffic alerting and collision avoidance system (TCAS) required to be installed on every commercial airliner.
Using signals transmitted from the transponders on board other aircraft in the vicinity of where an airliner is flying, the TCAS equipment calculates whether another aircraft is on a course which would bring it too close for comfort.
When the TCAS predicts closure with another airplane, it selects the best maneuver to get away from the other aircraft and produces both visual and aural signals to tell the flightcrew what to do.
Pilots are required by Federal regulation to do what the TCAS says without question or hesitation.
According to some passengers on Flight 94, the aircraft made a sudden climb which they found to be very scary. The maneuver would have been the flightcrew’s response to a TCAS resolution advisory.
The fact that there was a resolution advisory means that the TCAS system worked as designed, and a mid-air collision was not possible as long as the flightcrew adhered to the resolution advisory.
As part of its investigation, the FAA will review data including air traffic control radar images in an effort to determine just how close another aircraft came to Flight 94, whether the controller could have or should have seen a loss of separation developing, and whether there was ever a real threat to the safety of Flight 94.
At 1:48:16, the controller cleared Flight 94 to reduce speed to 160 knots and to descend to 2,000 feet. She advised the flightcrew that their speed was compatible with the speed of traffic they were following to the airport, and were cleared for the visual approach to runway 34 at Westchester.
The captain of Flight 94 acknowledged, “Cleared for the visual [to runway] 34, JetBlue 94. More excitement than I needed today.”