Sabreliner 40
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 90; Flight Crew Total 10950; Flight Crew Type 5500
Communication Breakdown; Situational Awareness
ATC Issue All Types
Air Traffic Control Issued New Clearance
Aircraft; Human Factors; Procedure
Local military authority recently instituted new arrival procedures returning to Navy Pensacola; (NPA); instituted an arrival fix of JERYS Intersection which is a GPS fix. T-39 aircraft are a slant 'Alpha' aircraft and being forced to navigate to a GPS point. On return Houston told us to proceed direct to JERYS Intersection. We began our TACAN point to point unwinded to that fix with our initial heading utilizing the TACAN fix the military had provided us. Houston asked us if we were direct JERYS and we replied we were. We made our first correction for wind while trying to conduct training with the student on point to point navigation. Again Houston asked us if we were direct JERYS because they showed we were going to miss it by 5 miles. We were still 50 miles away from JERYS at the time and made another correction. Told the Controller we were a Slant Alpha aircraft proceeding to a GPS point and our navigation would not be as fine as a GPS equipped aircraft. Controller responded the military said we could do this. Told him we were doing the best we could with our on board equipment. He said he would bring it up through his airspace management coordinator with the military and I told him I would do the same on our end. If this procedure is going to continue as published; then Houston needs to understand that a Slant Alpha (TACAN only) aircraft's navigation is not going to be as fine as a GPS aircraft especially on point to point navigation. If an agreement can not be reached with Houston and the military on this; then we need to return to our old procedure of TRADR Intersection which is a TACAN fix.
Military aircraft inbound to NPA with slant ALPHA equipment was cleared direct to a newly developed GPS fix and then questioned by ATC reference the less than accurate track being flown.