2. The aircraft was following a near perfect profile when at approximately 69 seconds of engine burn time the engine shut down and instrument panel warning lights began coming on. Also all T/M, radar, and communications were lost at this time.

3. The sequence of warning lights as ascertained from the cockpit film was:

a. Gross malfunction (inertial system computer)

b. Three SAS lights and vibration malfunctions (engine)

c. Number two generator out light

d. All lights and camera cockpit went off indicating complete electrical failure

4. The above sequence was verified to have happened in seven seconds from cross checking camera pulses on internal data film with data time codes.

5. The pilot reported that there was no aircraft response to control inputs and that the side stick would not move full throw indicating a complete loss of hydraulic power, since failure of a hydraulic actuator to move limits stick travel.

6. The pilot tried the BCS controls and verified that they fired but that they did not give complete control at that altitude.

7. Knowing that the APU's cannot be restarted in less than 24 seconds from shutdown, the pilot turned the #2 APU switch to the off position and waited that time period. Then he turned it on but nothing happened.

8. He then turned #1 switch to "OFF" position and then remembered that the emergency battery is required for APU re-start. He turned the battery on, then turned #1 APU on and heard it wind up.

9. He then made a successful re-entry and landed at Mud Lake.

10. The landing was made without flaps or third skid since they were wired to the main D.C. bus which was dead.

11. Due to the above conditions, landing loads, as indicated by skid marks were extremely high and the slideout measured 9050 feet.

12. The pilot reported that the canopy was difficult to open. Normal opening requires that the canopy seal he deflated before the canopy can slide aft. First motion of the canopy opening handle by the pilot unlocks the canopy and vents the seal. Tests in the hangar with X-15-3 show approximately 15 seconds time required to vent. the seal completely. During the time the seal is inflated movement of the canopy will be very difficult

The canopy opening connecting rod was not broken by the pilot as reported in a previous rumor. The rod was broken during ground handling on the following day after several additional cycles of the canopy. It is, of course, possible that the force applied by the pilot in trying to open the canopy weakened this rod.

13. The pilot also reported difficulty in disconnecting the suit-to-seat disconnect. Since he had not turned off the suit vent nitrogen system, it is probable that the N2 pressure through the disconnect increased the unlocking force by placing the disconnect halves in tension (Subsequent tests in the hangar verify that the unlocking force rises significantly when tension is applied to the disconnect halves).

14. At this point the pilot removed his helmet for better visibility and elected to pull the restraint release handle which beside releasing the restraint, fires the head rest deploying the chute.

15. When the head rest fired it struck the raised canopy with enough force to tear the inner skin, crack the left inner windshield and bounce downward striking the pilot a glancing blow on the back of the head.

2. Apparently the #2 generator failed with a clean loss of output to initiate the ensuing loss of electrical power. There is no indication of #2 APU failure, since T/M was lost abruptly at this point, and there are no APU parameters on internal data. Likewise there is no indication that APU #2 did not shutdown.

3. #2 generator currents, which are recorded internally, drop to zero and there is a slight increase in #l generator currents indicating that it had picked up at least a portion of the load. The actual increase in load on #l generator cannot be determined since the monitoring devices appear to have reached full scale output just slightly above normal load for the generator.

4. The internal recording of #l Af voltage indicates an intermittent voltage signal similar to that caused by turning the generator field exciter on and off rapidly for the seven seconds prior to complete electrical failure.

3. The upper and lower elevators were removed and internal film drums unloaded so film could be processed.

4. Then the APU compartment panels were removed and areas were visually inspected with no evidence of failure found.

5. During all area inspections there was no evidence of electrical shorting or burning as usually evidenced by a pungent odor.

6. At this point the APU turbines were motored with GN2 and both generators produced approximately 110 volts on each phase.

7. Electrical system, protective panel functional tests were made and no malfunctions were found.

8. Functional tests of the APU controllers were made. Both controllers checked OK except for a small frequency deviation in the #1 controller. (Approximately 4/10 of one cycle in one of the control circuits, which is not thought significant at this time.

9. A complete APU ground run was then made. No failure of any kind was discovered. Both generators reset properly and both carried the normal test loads applied.

10. The power panel in the elevator bay was opened for inspection and several frayed and scraped wires were discovered. These were traced and found to be #2 generator Af and Bf and D.C. bus lead wires. Also angle of attack, longitudinal trim, a valve heater wire and #2 Af voltmeter lead. No evidence of arcing or shorting was discovered.

11. Since none of these could be directly attributed to the cause of failure they were taped temporarily.

12. System check of the engine was normal. Additional checks revealed the engine circuitry would cause failure when D.C. voltage was lowered to 24 V D.C. which is normal.

13. A propellant system functional check, an in-flight SAS check and operational runs of the inertial system and MIT experiment were made satisfactorily.

14. A combined engine/APU run with all systems turned on (except C band radar beacon) was then made.

During the run the following major items were performed.

2. The #1 generator currents were seen to increase very similar to that seen in flight. However, there was no indication of fluctuating #l generator voltage as seen in flight.

3. The electrical load experienced on the ground run appeared to be slightly higher than that recorded during the flight.

One reportable item, however, is that the armored electrical harness from APU #2 tach generator was found to be kinked, and when submitted to a Hi-pot test, discharge was indicated between the tach generator wires and the armored covering. If the tach generator signal should short to ground the APU will shut down. Therefore, this harness is a possible suspect .

2. It is suspected that correction of the APU failure in X-15-1 will require complete re-wiring of the APU/generator control circuits although it is too early to make this a firm recommendation.