Date: 201603
Local time of day: 1201-1800
Location: TEB.Airport, NJ
Flight conditions: VMC
Light: Daylight
Aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb
Airspace: Class D TEB
ATC / advisory: TRACON N90
Reporter organization: Air Taxi
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure
Primary problem: Procedure

Narrative: We were initially given the Ruudy5 SID. After reviewing the route I realized that this route was an RNAV SID and since our aircraft is unable to maintain RNP1 I called back and informed Clearance about this fact. We then received TEB1 as our new clearance. About an hour later we loaded our passengers and got our clearance to taxi out to Runway 24. After taxiing to 24 and we were cleared to take off and fly runway heading. All normal so far. After going through our normal takeoff procedures on a heading of 240 we were leveling off at 1500 ft MSL before making the turn to 280 as stated in the SID. Before making the turn the controller inquired as to whether or not we had already made the turn to 280. I replied that we were still on 240 as per the SID. After this is where I think things went awry. I heard the controller come back with turn Left 270. This confused both me and my captain. I turned to him and asked him if heard the same thing that I did. He said that he did and I keyed back in to ask if the controller meant to say left. Again he came back with turn Left 270. My captain keyed in and said something about seeing an aircraft to the left and not wanting to get that close. I believe he reiterated 270 and a left turn one more time but I can't be sure. Then a couple of moments later he came back with make an immediate right turn to 270 and climb to 6000 ft; which made more sense. My captain made the turn and began climbing and we continued on until about halfway through the flight and then we were asked to make a phone call after we landed. After landing my captain called the number and after the conversation with the controller's supervisor we were told that the controller was saying 'West' instead of 'Left'. I'm not sure what any of us could have done different except the controller could have stuck to standard phraseology by saying turn Left/Right to 270 instead of saying 'West'.


Second narrative: Our flight had departed TEB Rwy 24 on the Teterboro 1 departure. Upon departure we were told by tower to contact departure and upon leaving 800ft we did. At 1500 feet we were told to turn left to a heading of 270 degrees. We told the controller 3 times that we were on a 240 deg heading. He reissued the left turn 3 times as well as a climb to 6;000 ft. Every time he gave us the instruction to turn left we asked him if that was what he wanted and he reissued the left turn. His instruction to turn left put us into conflict with a 757 that was on approach to EWR. Subsequently I was told to call ATC when I got on the ground. I was told by the supervisor that after having reviewed the tapes and listening to them several times she and another coworker determined that the controller in fact was saying turn west. We never heard him say turn west. Each time we heard the controller say turn left. The controller's nonstandard phraseology and repeated use of it was the sole reason for the misunderstanding in this scenario.


Synopsis: Air taxi flight crew reported departing TEB and being given instructions by ATC to 'turn left' from 240 to a 270 heading which would put them in conflict with traffic during the turn. After querying ATC multiple times they were given a right turn. Later conversation with ATC revealed the Controller was using nonstandard phraseology by saying 'turn west' which the crew misinterpreted as 'turn left.'