Safety Chase Flights
Norvin "Bud" Evans,
USAF flight test pilot of all models of the F-104 A, B, C, D, G, CF, and J models at Edwards AFB, California starting 1956
Chief Test Pilot Category I and II and USAF Flight Test Advisor on Category III
Commander of the Fighter Test Operations Division at Wright-Patterson AFB 1963
During my time at Edwards AFB one of the most demanding and least recognized jobs of the Edwards AFB Fighter Test Operation's pilots was that of performing "Safety Chase" flights. The purpose was to provide an extra pair of expert eyes to observe a high risk experimental test flight. This requires the chase pilot to fly on the wing or close proximity to the aircraft that was performing a "High Risk Test Flight". We flew safety these chase flights on Air Force, Contractor or NACA (NASA) critical test flights. We also flew chase all of the flights on the "X" type aircraft. Most of the flights required 3 chase aircraft during the time I was there (1956 -1963). I personally flew many of those chase flights and flew in all three positions.
If you were to analyze the flying hours of all fighter test pilots at Edwards during those days you would find that the number of support (Chase) flights were greater than the number of the actual experimental test flights. Not to lower the risk involved in the testing of new aircraft but the demands on the chase flights is much under rated. The basic reason for assigning experienced test pilots to fly in close proximity to an aircraft that is involved in a flight test is that we were trained to understand the purpose of the particular data that was expected by the test aircraft. In the unfortunate event that the test aircraft suffers a catastrophic failure while achieving the critical data point, we would be capable of giving an educated aerodynamic description of what happened.
One of the chase jobs I really enjoyed was that of flying any one of the 3 positions on the "X" rocket aircraft missions. The No.1 positions was that of close chase at launch which required the chase pilot to fly close to the "X" aircraft's Mother-ship, (B-29, B-50 or B-52) and the chase pilots job was to observe the rocket ship for anything that was not normal prior to and during initial flight after being dropped from mother ship. In the case of the B-29 and B-50 mother ship, in which the "X" aircraft was carried in the belly prior to launch, it was not possible for the engineers to observe the signs of any leakage or proper venting when the rocket fuel tanks were completely filled. It became part of the close chase pilot's responsibility to report all of those observations to the Mother ship.
The" Close" chase pilot should have flown one or more photo chase flights before being assigned this responsibility. The 'Photo" chase was flown in any two place aircraft that was capable of staying with the Mother-ship up to and including the launch of the "X" aircraft.
The Primary Chase was generally flown using the F-104 Starfighter. This job required real timing and could only be done accurately when the countdown and launch of the "X" aircraft was un-interrupted. As primary chase you started your run-in at 4-5 miles behind the gaggle of aircraft. You stroked the burner your goal was timing the launch so as to have the drop and engine start of the "X" aircraft while still in front of you. Keeping clear of the photo and close chase aircraft you passed the "X" aircraft while you were approaching Mach-II. The perfect profile was for you to be stabilized at Mach-II when the rocket ship caught up and accelerated past you. Most of my chase flights were with the X-15, although I had several with the X-1E and the DD-558.
Your job as "high speed chase" really takes on a demanding effort as you have to place all of your attention on keeping the rocket ship in sight as it climbs up into the dark blue sky. This is easy as long as its engine was still burning leaving a trail of white smoke and contrail. Your most difficult task was to glance occasionally at your instrument panel so as not to exceed the engine front frame temperature or 50,000 feet altitude. Once the rocket motor burns out the rocket ship is just a tiny spot against the very dark sky. It was surprising that the X-15 being painted all dull black in color appeared silver when contrasted against the deep blue sky. By this time you come out of after-burner but you don't dare look at anything but the tiny speck that is your responsibility. You must join up with him and help guide him back to the lake bed landing. Flight test radar tries to keep track of both of you and is some help if you lose sight but the X aircraft usually is descending so fast that their directions are not much help. For that reason you do everything possible not to lose sight of him. Once you have solid visual contact with your "target" it gives you the first opportunity to check your own instruments for any anomalies. Many of our early chase flight with the F-104 were made while the "Starfighter" was still in "Test Status"! Fuel level was also a very real concern as you were normally in A/B for a long time which consumed a great deal of fuel.
As soon as you joined up on the wing of the test aircraft and assessed your position to the lake bed runway your task was to check over the rocket aircraft for any unusual signs of damage. This was accomplished while he was heading rapidly towards the lake bed and his aimed landing spot. You had to fly completely around the aircraft and then read off airspeeds and altitudes while checking your headings and making sure you are on a proper pattern to make the landing area. At about 5,000 feet you begin to call out altitudes and when you slow to 225 knots airspeed you drop your landing gear. Then at 100 feet you begin to call out speeds and altitudes. You confirm gear or skids extended and then call altitudes above the ground such as 25 feet, 10 feet 5, 4, 3, 2, 1. Usually you actually touched down before the "X" aircraft but you never looked at your landing position and you knew you were on the ground when you felt the touchdown. As soon as the "X" machine was safely on the ground you once again took control of your aircraft and climbed back into the air, made a tight pattern and landed on the main base runway.
Chase flights were not routine flights and were responsible for a number of accidents and deaths of experienced USAF test pilots. Most notable but certainly not the only good pilot lost was Capt. Ivan Kinchloe, Korean War Fighter Ace. I was scheduled to fly chase on a Lockheed F-104 on a Saturday morning. There were two chase flights scheduled on that Saturday morning, both with our F-104's chasing Lockheed F-104's. My flight had been briefed late on Friday afternoon so that I could get off early on Saturday morning with only having to do anything but co-ordinate the take-off time, join-up altitude and location.
I had joined a group of our pilots at the club for our usual "Friday Night Happy Hour" when Kinchloe showed up. He had just arrived back from an evaluation trip to Europe flying some of the Western European newest fighters. He asked our Chief of Flight Test if he could take one of the 2 scheduled Saturday morning flights and was told to take the one scheduled for the other pilot who was assigned to the second chase mission.
I arrived at operations just shortly after daylight and Ivan was only a few minutes behind me. I suggested he take a nap on the couch in operations while I took the first flight and I told him I would call him on the radio to let him know when I was on my way back to Edwards to land. (We were required to have a test pilot standing by on the ground radio whenever a flight test aircraft was in the air). My mission required that I take-of and climb in afterburner to 35,000 feet. I picked up the contrail of the test F-104 and was on his wing as we leveled at 35,000 feet, stayed with him out to Mach 2 where he performed his test data point, then returned to land at Lockheed's plant at Palmdale, California, about 45 miles from Edwards. I stayed on his wing until he touched down then headed back to Edwards. I called test ops and told Kinchloe that I was on my way back and that he could head out to his F-104 for his chase flight.
After landing I taxied back to our ramp area and parked next to the aircraft that "Kinch" was climbing into. By the time I filled out my post-flight paperwork and climbed out of the cockpit we saluted each other as he taxied out.
Throughout our lives, particularly those of us who spent many years working in hazardous professions, we can look back at times when "Fate" has selected someone else to pay the ultimate sacrifice when it could so easily have been you.
There are many interesting events that occurred to me while flying chase on other test missions and have been very happy to have one of my fellow test pilots flying safety chase on me when unexpected things occurred to my aircraft. I believe I could write an entire book just on the exciting things that have occurred to me while flying "Chase" missions. It is a serious and often overlooked part of "Experimental Flight Testing"!
|Copywrite by Norvin "Bud" Evans
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|Compiled by: Hubert Peitzmeier|
November 28, 2008
November 28, 2008