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Air Test

Turbo Tarling's private casebook:

I had been at VU-32 for a year and had just recently been appointed OC Jet Flight. During that year I found that the navy (dark blue) and the air force (light blue) had different ways of doing the same thing.


The T-33 full-card air test was spelled out in the AOIs, step by step, so there was no room for differences in the procedure. It seemed, however, that the navy pilots preferred to yank out the rear seat pack, tie up the back seat, and blast off on a solo mission to perform the air test. On the other hand, I considered it a great opportunity to take the younger, inexperienced pilots up with me so they could see, firsthand, how it was done.


On July 5, 1971 Lt. John Crowe, a light blue pilot, and I were scheduled to do a full-card test on T-33 499. John would fly front-seat and I would take the rear, talking him through the air test sequences and filling out the card as we went along. John was an enthusiastic pilot and was enjoying putting the bird through its paces. Next item on the card was the negative G test.


The negative G test was my least-favourite air test manoeuvre but it was essential to give the bird a clean bill of health. First on the agenda was a thorough inspection of the cockpit, stowing anything loose – anything overlooked was sure to find itself floating through the air and pinned to the top of the canopy where it could be deftly plucked if you were quick enough. Next, the seat straps were cinched-up good and tight, a good look-around outside to clear the area, then into the manoeuvre.


Just as briefed, John lowered the nose of the bird, picked up a head of steam going downhill, pulled smartly back on the control column to get us going back uphill, then bunted forward to give us the required –2G for 5 seconds. The usual dust and minor debris floated up off the cockpit floor but what got my attention was a solid column of rust-brown liquid that seemed to be coming up from my control column. It has just taken you 20 seconds to read this paragraph – four times the negative G test. Suffice to say, time was suspended and rolled forward frame by frame during those 5 seconds of negative G.


The brown column of liquid then pinned itself on the canopy and started rolling forward towards the front windscreen, right over John’s head. I started to giggle because nothing was going to stop the next sequence of events, and John asked what was so funny as we sat pegged at exactly –2G. The uncomfortable 5 seconds were now over and John began his recovery by pulling back on the control column and giving us positive G again. Down came at least a litre of the brown messy liquid, right on John’s helmet, immediately followed by a bunch of expletives!


During the ground inspection they found that water had accumulated in the bottom of the canvas-covered control column well from heavy rains and moisture over a period of time. That would explain why the control columns would get “sticky” at high altitude as the water turned to ice. The fix was the installation of a simple automatic water drain valve and the problem disappeared. Chalk up another win for the negative G test.


Captain (A) Turbo Tarling (Ret.)
VU 32  1970-1973