Flight: 3-4-8
  Pilot: Neil Armstrong
    Takeoff -- during the prime, the cooling procedures didn't apparently. work quite as well as they had on our previous flights. The analyzer check and the flight control system was satisfactory.  I chose not to re-examine item 8, which had a temporary failure because of center stick trim. I really wasn't very concerned that it showed a temporary failure, it indicated that we were quite close to where we needed to be and there wasn't any use worrying about it. I was sure that the analyzer would never pass anything while in the turbulence we were encountering at the time, which was the most severe that I have had to ride through in the B-52 and it was an altitude of 45,000 feet. We had sizable gust loadings and side slips throughout as a result of these.

    In the pressurization and jettison check I had every intention after the lesson of last flight of putting the peroxide jettison switch to stop at the completion of that check, and I neglected to do it. Pump idle was smooth with few oscillations. The size of the pressure was pretty sizable though about 390 or so manifold pressures and pump idle were solid. The light was good. I was surprised that the chamber pressure wasn't as high as we had seen on the ground run. I called it out somewhat later in the flight around 575 or something like that. It was about 20 pounds below what I had seen before.

    I made the pullup on trim. 3 units of nose-up trim on the side stick. This seemed to be a little bit slower than it had been on the simulator. I got to the pitch attitude at 32° after 35 seconds of flight, if I remember correctly. I put the pitch rate trim to zero at  theta = 32°. and I was reading Joe fine at this time and pushed over at 35 seconds. At 50 seconds, which was our speed check point, we were indicating 3100 feet per second inertial and about 65,000 or 70,000 feet in altitude, which was very close to what we had expected at that point. I pulled up on Joe's count of 55 seconds with a pitch rate trim of 5 units. This was also somewhat slower than it had been on the simulator. I had engaged roll hold earlier at 15 seconds without transients. I engaged theta hold at approximately 70 seconds, without transients. The airplane flies 100% better than the simulator on this theta hold. The simulator had indicated that the airplane pitch damping at this condition would be poor but it was not. Damping on all axes was good. I had 81 seconds on my clock, maybe one second before when it was called on the ground. I shut down on my clock so I was in the cutoff position about the time that I got the call from the ground, 81 seconds. You indicated I was slightly steep on profile and my indications were that I was about 30 to 30-1/2° at this time. Since we had a difference of opinion on what our condition was I chose to leave it at 30 -1/2 ° for the burnout and that's the condition we were at instead of the 32° that we had planned. Rather than make a little correction downward when you said I was a little steep or upward from what I indicated, I took the happy medium. I engaged alpha hold and used CSS to reduce alpha and then alpha trim a little to reduce alpha to zero. That operation was all satisfactory.  I put in several pulses and control steps in the area of the peak altitude and noted that the airplane did not move as far in heading, side slip, or roll attitude for the same stick deflections as we had seen on the simulator. I was aware that the reaction controls were working satisfactorily although there was no apparent noise. The reaction control damping is exceptionally good. It flies as good as the airplane does on aerodynamic controls at low altitudes. But, obviously. at the expense of a considerable amount of peroxide.

    I read about 5700 ft/sec at engine burnout. Since the velocities were predicted to be fairly good and we had indicated slightly fast on the 50 second point, it was assumed that this was about right or possibly reading a little fast. We have had performance to 5700 ft/sec on the simulator for 82 seconds of burning. The altitude rate on top and the inertial system was 210,000 feet and cross-checks of the inertial system indicated it was working satisfactorily.

    During this time period, after 81 seconds, I didn't receive any transmissions from NASA 1 and didn't receive any transmissions from that point until the middle of the entry. I did receive a number of transmissions through relays. I'm not quite sure who it was but these transmissions were weak, about strength 2 and modulation 3 to 4. I might say that I did some specified roll maneuvers at about 20° angle of attack and the returns were satisfactory. The airplane returned to the wings level attitude with essentially no sideslip. At about 15° or 16° angle of attack and 4 g, I elected to leave the angle of attack in that mode and I was hoping that I would see the g limiting in action. We had seen g limiting on the simulator operation at levels approximately 4 g to 4-1/2 g and it wasn't obvious that we were having any g limiting so I left it at this 4 g level for quite a long time hoping that this g limiting might show up. It did not and apparently this is where we got into the ballooning situation.

    At this point I heard the second transmission from NASA 1. The first one that I heard from NASA 1 was, I believe, when he called out some angle of attack which I correlated with and I think he mentioned a similar reduction but I'm not sure. The next transmission I expected from my simulation work was "you're about 20 miles north," but the transmission I got was "turn hard left."

    We had planned on going down to 6° angle of attack in this area, and have a little time on the way in for the last 20 miles to build up the q, kill off a lot of altitude and get some pulses on the adaptive mode. With the left turn command which I followed with 60° left bank angle and 15° angle of attack, I did not properly appreciate the altitude I was at. I was apparently at an altitude above that which I had expected to be and which caused me to go sailing merrily by the field. As I saw Palmdale going by I was in a 90° bank angle and essentially full deflection on the stabilizers, between 25° and 35° on the stabilizer indicator. We were having no heading change. The proper thing to do at that point would have been to roll to a greater bank angle, greater that 90° bank angle and try to get that thing down to a lower altitude so I could turn faster. However, my indicated airspeed said 190 knots and that seemed from my past simulation experience, to be what should have been adequate to turn the heading but it really wasn't. Finally I did allow the nose to drift down and picked up approximately 350 knots indicated airspeed and was able to get about 3 gat this point. I began to turn back home and it looked at this point as though I would have no difficulty making Edwards. The only other alternative at that point would have been Palmdale and I didn't want to get into their traffic pattern. Mirage Lake was about as far away as Rogers and Rosamond wasn't much closer, so I decided to head for the south lake. It looked like we were in good shape. I jettisoned then and again it didn't occur to me to stop peroxide. I had promised myself that I was going to have peroxide in a stop position but I did not. We threw a lot of peroxide away that we would have had available for the transfer system.

    The impression that I had as we approached the field was that the airplane wasn't making good the L/D that we had practiced in 104 approaches around Edwards. I was flying at approximately 270 knots and had I suspected that we would have been tight.  I would have jettisoned the ventral but it didn't even occur to me that we might be tight. As we approached the field however, I found out that my aiming point that I had selected would have to be movcd back approximately 2 miles from where I had originally picked it up. In coming furthcr out down here I lost approximalely 2 miles in length from what I thought I would have. I may have had a control condition at this time which I did not know I had. When I was in the flare I found that I had to use large pitch motions on the stick and it was a real sloppy flaring touchdown. This leads me to believe that possibly I was overpowering pitch attitude hold or had normal acceleration feedback, or something in the system. We will have to check that. It was a pretty sloppy flare and a slow touchdown, probably 165 knots, something like that.

    Q Do you recall turning off the alpha Hold after the entry?

    P.C.: No, I don't remember. It points out the need for something that I thought might be a valuable addition to the flight control system. This would be an outer loop disengage switch. I think we should consider this, someplace where we could get at it from the stick.

    Q How about on the ventral jettison switch?

    P.C.: Well, that would be an idea certainly for landing. There might be other times when you would want to use it also. It's something to talk about.

    Additional unrelated comments are as follows :

    1. Smoke was observed emanating from above the instrument panel at 90 ,000 feet during the entry.

    3. The newly installed FCS indicator lights operated satisfactorily but can be considered only a temporary 'fix'.

    5. The stabilizer position indicator operated satisfactorily and was readable at all times. It is considered to be a valuable addition to the panel.

    7. Radio reception at high altitudes was generally unsatisfactory.

Copy of final comments document scanned as an image:

Photocopy of supplemental X-15 pilot report by Neil Armstrong