Medium Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Confusion; Distraction; Communication Breakdown
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Airspace Structure; Chart Or Publication; Human Factors
Departed ZZZ for HPN with a clearance of ZZZZZ SID ZZZ; Pontiac; DNY; direct HPN. Entered PSI for Pontiac instead of PNT. Both identifiers are for Pontiac (one in Illinois and the other in Michigan). On climbout; while passing FL270 we made the turn to PSI (to the right); and the Controller queried us if we were proceeding to Pontiac. We acknowledged 'Yes' but she said it should be a left turn to PNT. It was then we realized we had entered the wrong Pontiac identifier. Both PSI and PNT identifiers stand for Pontiac and they are only 259 NM apart in the same direction of our route to HPN. After verifying the route and desired PNT identifier we proceeded in the correct direction. BTW; the flight plan filed did not have Pontiac on the route of flight. So when verifying the route; PSI stood for Pontiac and we assumed that was the correct identifier.Event was detected by ATC when we did not make a left turn towards PNT after SPI but a slight right turn to PSI. The event happened because Pontiac has two identifiers and the Controller never specified the one desired or cleared to when he gave us the clearance on the ground. Second; Pontiac identifier (PNT) was not in our filed flight plan which might have helped us identify the correct and desired Pontiac to go to. Third; both crew members were not aware of the existence or distinction between the two separate Pontiac identifiers so close together.After verifying with ATC the correct Pontiac desired (PNT); and the remainder of the route to HPN; we proceed to make a left turn direct to PNT.After receiving clearances; verify the cleared to identifier points by crosschecking the filed flight plan route or the route depicted on flight aware; or query the Clearance Delivery personnel if an identifier is in question and not on the flight plan filed. Second; would recommend not having two Pontiac identifiers so close together (259 NM apart); if it can be avoided. Or if not possible; then controller should clearly state the correct identifier by phonetically spelling it or telling us the state it is in.
Upon picking up the clearance on the ground; I was given a route of 'ZZZZ SID Transition Pontiac DNY direct HPN. I didn't know the Pontiac identifier so went to the iPad route map in Jeppesen view. Scrolled the map up to where Pontiac MI was and plugged PSI in the box. Although it seemed like a strange clearance I checked flight plan mileage with actual route mileage and it was only 20 miles off the flight plan sent from the company. As we were climbing through 28;000 FT ATC asked us if we were going direct to Pontiac. I responded with 'Yes' we are direct Pontiac at this time. She told me to read our route to her; and as I read the route to her she responded with we were cleared to Pontiac DNY Direct and that Pontiac was about 20 degrees left. We then had her spell out Pontiac and she responded with PNT! This fix PNT is Pontiac Illinois and I had Pontiac; PSI; Michigan in the box. Nothing else was mentioned after I fixed the box and we carried on. Detection happened when ATC asked us what our routing was; and was informed that we needed to be 20 degrees left I believe this event happened due to the fact that there are two Pontiac fixes within 259 miles of each other which to me is a technical error. Once ATC spelled out the fix they wanted us to go to I put it in the FMS and we kept going. Personally; I don't see how they can have two fixes with the same name within 300 miles!
Pilots report of similar sounding VOR's which caused confusion when the entered the flight plan in the FMS. This caused the aircraft to deviate from its flight plan.