N406CTCessna S550 · 1985

The first loss of separation involved PH-ILC, a Netherlands registered Dassault Falcon F900 departing TEB, Fivestar 604, a Cessna C680 arriving TEB, the TEB air traffic control tower (ATCT), and the New York Terminal Radar Approach Control Facility (N90). The second loss of separation involved FIV604 and N406CT, a Cessna C550 arriving TEB, TEB ATCT and N90.

TEB was on a south flow, landing runways 19 and 24 and departing runway 19.

Teterboro Class D airspace, encompassing the Teterboro Airport, located approximately 12 miles northeast of Newark Liberty International Airport (EWR), underlies the New York Class B airspace. The majority of the New York Class B airspace is managed by N90 which provides air traffic control services to Teterboro Airport, Newark Liberty International Airport (EWR), John F. Kennedy International Airport (JFK), La Guardia Airport (LGA) as well as numerous other smaller airports in the New York/New Jersey area.

TEB Class D airspace is relatively restricted airspace defined as that airspace extending upward from the surface to and including 2,500 feet mean sea level (MSL) within a 4.2 mile radius of TEB. The airspace overlying the TEB Class D airspace is used primarily for arrival traffic into EWR. Accordingly, aircraft operations into and out of TEB are tightly managed and metered by N90.

On the evening of the incident, the traffic in the airspace above and in the vicinity of TEB was busy with successive arrivals and departures to and from TEB and EWR.

The first loss of separation sequence began at 1905, when the TEB local controller (LC) cleared the F900 for takeoff from runway 24. After transferring control and directing the F900 to contact N90, the F900 advised the LC that they had "an abnormal at the moment" and wanted to return to TEB. The LC directed the F900 to enter right traffic for runway 19 and was initially sequenced in front of the C680 on a four mile straight in visual approach to runway 19.

The C680 had reported his position to TEB and was directed to maintain minimum approach speed and plan to follow the F900 on a right downwind for runway 19 with a possibility of entering a right base for runway 24. The LC then advised the F900 that he would be number 2 in sequence following the C680.

The LC asked the F900 if he required assistance and was advised that no assistance was required, but that the aircraft was experiencing a fuel light indicating a possible leak or a bad switch. Neither the LC nor the F900 declared an emergency. The F900 was not provided IFR handling though it was on an IFR flight plan.

LC attempted to coordinate with N90 MUGZY arrival sector to take the C680 out of the approach sequence and re-sequence the C680 to allow the F900 to be sequenced in front of the C680. The N90 MUGZY arrival controller advised the TEB LC that the C680 had already been directed to contact the TEB ATCT, but said the TEB LC could "do whatever you want" with him.

The TEB LC then instructed the F900 to turn base leg. As the F900 began his base leg turn LC instructed the C680 to enter base for runway 24 and 9 seconds later redirected the C680 to continue for runway 19. The flight paths for the F900 and the C680 were converging. LC then issued a traffic advisory to the F900 referencing the C680. Traffic was issued as "traffic at your eleven o'clock, correction one o'clock, 2 miles, a citation". The F900 reported the traffic in sight and was directed to follow the traffic.

The TEB ATCT cab coordinator (CC) who was also the TEB ATCT Front Line Manager (FLM) attempted to assist with coordination between the N90 Newark East Departure Coordinator, the N90 FLM, and the TEB LC.

N90 directed that the LC direct the C680 commence a left turn and a climb to 2000 feet. This caused the LC to abandon her planned aircraft sequence and the LC instructed the C680 to start a left turn immediately and to maintain 2000 feet. As the C680 was turning, the F900 overshot and flew through the final approach course for runway 19. This resulted in a loss of separation between the F900 and the C680 with a closest point of approach of 100 feet vertical and 0.6 miles lateral. The F900 was subsequently cleared to land on runway 24.

The second loss of separation occurred when the C680, still in a left turn at 2000 feet, came into a conflict with N406CT, a C550, on approach to TEB. Seeing the developing conflict between the C680 and the C550, N90 directed the C550 to climb to 3000 feet and asked TEB what heading the C680 was on. The C680 reported that his heading was “forty degrees continuing a turn to the left”. The LC advised the TEB FLM that the C680 was heading 040 degrees which was relayed to the N90 controller working the C550. The TEB FLM relayed to N90 that the C680 was on a heading of 040 degrees. N90 then directed TEB to have the C680 climb to 3000 feet. The TEB LC directed the C680 to climb to 3000 feet and, thinking the C680 was on a steady heading, directed the C680 to commence an immediate right turn to de-conflict from the C550. The C680 advised they were in a hard left turn with traffic to their right and did not comply with the TEB LC. The C680 and C550 came within 200 feet vertical and 0.44 miles lateral of each other.