Military aircraft inbound to npa with slant alpha equipment was cleared direct to a newly developed ...

Narrative:

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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1015756
Time
Date	201206
Local Time Of Day	1201-1800
Place
Locale Reference	ZHU.ARTCC
State Reference	TX
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Sabreliner 40
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Captain Instructor
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 90 Flight Crew Total 10950 Flight Crew Type 5500
Events
Anomaly	ATC Issue All Types

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.