How Accurate Was A 'Three Star Fix?"

 

I remember a technique that an Instructor Nav showed me when I was doing my Initial Checkout in C-124's right out of Harlingen.

 

It was called a "running fix," and was used for "three-star." The technique required a shot four minutes early, a shot on time, then a shot four minutes late, and you would move the early and late shots for groundspeed. My Instructor Nav also suggested that you alternate the 'on time' shot between a speed line and next a course line, since the on time shot was the most accurate, you kept better track of your course and speed that way.

 

This was a technique that I used right through my time in the 'high-altitude' RB-57F (my last job as a nav), and it always worked well for me! In the long wing "F" model, I always pre-comped all my celestial on the ground the day before the flight so that all I had to do was shoot and plot in the air and this technique worked well and more importantly, it was fast since there were a number of other things to be done during the same time that I was navigating...

 

Our long range, over-water repositioning flights were always done at night so that we had good accurate navigation, and done carefully, that weird and strange fixed sextant that the "F" model had, could give very accurate results. I didn't do my pre-comps early on these flights since I had nothing else to do, and on a trip from Pago Pago, American Samoa to Hickam AFB, HI, late one dark night, I made a beer bet with my pilot in regards to the ETA for TACAN "ring-in" (from Hickam) which was when the old TACAN would lock on at 199 nm, which was it's max range. We would start down shortly after that point.

 

About an hour before the expected Tacan point, I started taking fixes as fast as I could comp and shoot, so I was very confident of my accuracy, and I gave him the ̉ring inÓ time to within :30 seconds, and as the time approached, he was chattering away about 'free beer' and at the exact ETA, which was on the half minute, NOTHING happened and he started cheering, but 5 seconds after that, the TACAN locked on at 199...!!!

 

He went dead silent and I started cheering and said I'll take the most expensive beer they sold, at which point he said he had never seen anything like that, and he had been flying the plane since the very beginning! I was on my sixth month in the bird, but kept my mouth shut about the back to back three star fixes I was taking since he might have thought that was cheating, and maybe it was, but in all my 4500+ hours of nav time, I don't think I was ever anymore accurate than I had been that night above FL600 on a beautiful, black, and starry night... Life was very good indeed!

 

Chris Neale

61-09N ~ 68G