X-15 OPERATIONS FLIGHT REPORT

FLIGHT NO: 1-63-104 DATE OF REPORT: 5/20/66

PILOT: John B. McKay DATE OF FLIGHT: 5/6/66

CARRIER AIRCRAFT: B-52 #003 LAUNCH LAKE: Delamar

ENGINE SERIAL: 103 APU #1 16AN APU #2 20AN

PURPOSE OF FLIGHT: 1. Atmospheric Density (Univ. of Michigan)

2. Micrometeorite Collector (ACRL)
3. Apollo Horizon Scanner Phase II (MIT)
4. Sky Brightness (Nortronics)
5. Stick Pusher
6. Non Glare Glass (a indicator)

I. Discussion of Previous Operations

A. The Micrometeorite Experiment was found to be extended after the emergency landing at Delamar. The experiment also extended during flight 1-50-79; adequate cause was not found for this flight during subsequent checks to explain the unscheduled opening, therefore, the control circuit was revised to simplify the system and provide manual pilot extend-retract action.

The experiment configuration includes an electric clutch brake and a gear train with high mechanical advantage which prevents the experiment from extending with power off. Inspection after flight 1-63-104 revealed a sheared gear shaft which allowed the negative "g" forces to extract the mechanism. For the past flight, procedures called for the experiment switch to be positioned at "OFF"; on future flights the switch will be placed in "RETRACT" to provide continuous power if the experiment moves to a position which actuates the closed limit switch. In addition to procedure changes, a beef-up of the failed gear shaft was incorporated and an adjustment of the retract micro-switch was made to insure that the mechanism was not contacting the mechanical limits and loading the gear train.

B. Because of the recent, numerous cockpit pressure failures which have been traced to cold environment of the cockpit pressure regulator, a study was made to select another location for the regulator. A layout was made for installation in the LH onboard rear corner of the elevator bay with the exhaust air ducted through the space between inner and outer skin and into the side fairing. A hole pattern was selected to provide an adequate exhaust path from the inner skin duct into the outer fairing area. The relocation proved satisfactory in operation as demonstrated on this flight with the extended cold soak experienced and the use of external air-conditioning air for the IFDS which, in the past, has caused malfunction of the cockpit pressure regulator.

II. Aircraft Configuration Changes A. Preparations were completed for flight, including the following changes, prior to termination of the flying season by rain on 11/5/65. 1. Engine S/N 110 was replaced with engine S/N 103 because of fuel pump shaft seal helium leakage from the cavity drain and the sluggish metering valve operation resulting in the undershoot experienced on the start and restart of flight 1-62-103.

2. The wing pod experiment installation included:

a. Micrometeorite collector in the LH forward position.

b. Skybrightness in the LH rear position.

c. The Air Density (University of Michigan) in the RH forward position.

d. Pod cone with ballast (22 lbs total) in the RH rear position.

The Autonetics IR Scanner was not ready for installation.

3. The MLG uplock hook, roller bracket and bracket fasteners were changed by NAA E.0. and provided increased strength; thermal differentials causing bowing of the MLG strut have caused higher loads in the MLG uplock assembly.

4. The stick-pusher system was completed and an operational check was satisfactory to qualify for inflight use.

B. Reschedule for 12/15/65 allowed additional configuration changes as follows: 1. The MIT Apollo Horizon Scanner Phase II wiring interface with the Honeywell IFDS was completed, and the experiment was prepared for flight.

2. A second digital converter box was installed in tandem with the IFDS display unit to provide the predicted altitude pilots display. The installation is located behind the pilots panel on bracket mounted to the landing gear pulley bracket.

3. The cockpit pressure regulator was relocated from the Sta. 200 bulkhead to the LH rear corner of the elevator bay with an air exhaust duct mounted to the inner skin; air discharge is accomplished between the inner and outer skin and into the side fairing area. Installation was made per ED-0-479 (sheet 1-5).

4. A switch to provide pilot control of the Pitch, Yaw and Roll RAS Solenoid Valves was installed. Leakage has occurred after APU H202 pressurization, and cycling of the valve can correct valve seat leakage.

5. The resistance type mixing chamber temperature indicator was installed because of shortages of the Hickok Gages.

6. The engine 501 power relay was removed from the engine D.C. circuit; D.C. power is now controlled directly with the master switch.

7. The aircraft electrical circuit secondary bus was installed to automatically reduce electrical load with loss of one generator. The RH windshield heater and one air-conditioning blower are powered by the secondary bus.

C. Rescheduling for 1/5/66, allowed continuing aircraft modifications: 1. A bracket for mounting the MIT-IFDS isolation amplifier box was installed above the T.C. commutator complex.

2. An added IFDS computer protection circuit was incorporated into the electrical configuration which signals the computer dump circuit when either alternator drops from the line.

3. The IFDS loader harness connectors were relocated from the elevator compartment to the cockpit LH rear console to allow IFDS reloading and trouble shooting without removal of the elevator lid.

D. Rescheduling for March allowed further configuration changes: 1. The PMR U.V. - IR tracker experiment lower elevator was modified for equipment installation and was fit into the aircraft, preparatory to eventual installation of the PMR experiment. Elevator wiring was affected by EO898950.

2. The wing pod disconnects were installed per EO808970, 971, 972 in order to provide configuration flexibility and to avoid necessity of the rewiring effort to remove and reinstall pods.

3. The forward fuselage beef-up for increased landing loads was accomplished per EO898992 (ECP X-15-218).

4. As part of increased landing gross weight capability, the aluminum nose wheels and 10 ply tires serviced to 295 psi were incorporated per EO900567.

5. The IFDS computer environmental air recirculation plate previously attached to the lower elevator frame was moved to the computer shelf structure. The plate produces an air recirculation condition between the exhaust and inlet blowers to avoid over-cooling the computer.

E. Additional configuration changes were made as a result of the rescheduling for 4/12/66: 1. The PMR elevator flip-top lid assembly was installed. Rework was accomplished on the hold down fittings, the seal mating cowl, and the main electrical power panel was moved aft approximately 3/4 inch.

2. A reconfigured pilots display panel and a revised pedestal switch panel were installed. (Fabricated per Sk EE-0-468, sheet 1, 2).

3. The fasteners at Sta. 200 on the lower 90° quadrant between longerons were changed to 7S36J-3A screws to increase shear strength. Portions of the inner elevator floor were removed for access.

4. A closeout plate was designed and installed to replace the heavy upper elevator. Approximately 50 lbs were saved on the installation. Fabrication was accomplished per WO 670-0-4548.

5. The a indicator was shortened by approximately (1) inch to clear an interference and to allow the conventional arrangement of the "G", a , and 3 axis ball indicator locations. The original instrument length interfered with the altitude predictor digital converter box after installation of the new pilots panel.

III. Preflight Events A. Deficiencies encountered during the preflight functionals required replacement of the following components:
1. Engine S/N 110 was replaced by S/N 103.

2. Both APU/BCS ON-OFF-JETT valves were replaced for a slow, incomplete cycle on one valve, and for leakage through the jettison port of the second valve. One stock valve was rejected for external helium leakage at a banjo fitting during the post installation checkout.

3. The cabin pressure regulator was replaced because of an off-schedule regulation of 38K of the previous flight.

4. The Lox vent valve was noted to have a crack in the valve seat. The stock item had a score mark across the sealing face of the adapter body requiring exchange of details with the old valve.

B. The stick pusher system performance was demonstrated at 3300 psig hydraulic pressure and 600 psig stick kicker source pressure, producing a horizontal stabilizer deflection of 13° degrees leading edge up in (2) seconds. The trim pot was set at zero degrees.

C. A series of flight date rescheduling was required by periodic rain and wet lake conditions. The various schedule target dates were 11/30/65, 12/14/65, 1/5/66, 3/1/66, and finally 4/12/66. Each reschedule period was occupied with configuration changes, some of which apply to future experiments.

D. Time compliance items and maintenance were accomplished and included:

1. The engine H202 press/vent valve was replaced for inspection. The engine H202 tank visual inspection was extended for an additional 6 month period beyond the yearly inspection due in April; each inspection has shown the corrosion pattern (which is peculiar to this tank,) has grown slightly, and it is suspected that most of the change is the result of exposure to the hangar atmosphere.

2. An on-board pressure transducer calibration was accomplished on 3/31/66.

3. An elevator bay area resealing effort was made to rejuvenate deteriorated sealing.

4. A 360 day ejection seat inspection and operation check was accomplished.

E. Aircraft functional checks were initiated on 4/1/66. One APU/ BCS ON-OFF-JETT valve was replaced because of leakage through the jettison port. The wing pod experiments including Skybrightness, micrometeorite, air density, and the MIT Phase II experiment were functionally checked during the period 4/4/66 through 4/5/66.

F. A successful engine run was accomplished on 4/6/66 with engine S/N 103. The manifold and discharge pressures were reversed at the engine patch panel. APU runs were satisfactory with a BCS demonstration included. An LN2 crocker valve was replaced because of failure to close in APU-Cooling-Single condition.

G. Pilot dissatisfaction with the new pilots instrument panel layout required relocation of the "G", "Q", and a indicator positions; the revision restored the original relative positions for best cross-correlation of gages during flight.

H. A cockpit pressure check on 4/8/66 produced a leakage rate of 85 CFM. Additional effort reduced the leakage to 81 CFM for flight.

I. Engine preflight functionals were accomplished on 4/18/66. The aircraft was ready for flight, however, X-15-2 was scheduled ahead of X-15-1. An aircraft basic weight was made at 14,288 lbs (minus any propellants and pilot).

J. The aircraft mating was delayed from 4/20/66 through 4/22/66 because of C-130 shortage.

K. Engine functionals were repeated on 4/25/66, however, the flight was rescheduled for 4/29/66 because of C-130 support and X-15-2 priority. All aircraft functionals were reaccomplished including a 30 day ejection seat inspection. The No. 1 air conditioning blower failed and was replaced. Normal APU runs were made on 4/27/66. Further delays in C-130 support allowed time for installation of the cockpit window shade, P/N 240-531286 intended to reduce the effects of afternoon sun glare in the cockpit.

L. Flight was rescheduled for 5/6/66 because of delays in X-15-2 and C-130 support.

M. On 5/5/66, the fourth in an extended series of engine preflight functionals revealed an intermittent S-9 chamber pressure switch in the engine control box. The control box was replaced and a satisfactory engine operation was accomplished. Post engine run functionals and aircraft closeout were completed by 0400 A.M. on 5/6/66.

N. Aircraft service was accomplished with some attending difficulties:

1. The B-52 hoist would not raise the mated aircraft to the level condition; a hoist condition of 11-3/4 inches up was obtained resulting in a 15 gallon ullage. A ground jettison was made in lieu of a flight jettison to compensate for the increased ullage.

2. At the request of high range, the PDM system was turned off during the flight service preparations to investigate frequency interferences. The commutator fuse was blown when the system was turned on; however, the T/M master switch was used instead of sequencing the commutator and master switch. The fuse was replaced with a 1 amp slow blow variety fuse.

O. A change in IFDS turn-on procedure was made involving turn-on of the IFDS flight initiate switch before removal of AGE to allow programming of an MIT Phase II Experiment requirement into the IFDS computer. IV. Flight Events A. Systems operation during the captive portions of the flight was normal excepting an IFDS 10° heading error and an Inertial Velocity of approximately 1200 FPS. Later testing in the Inertial Laboratory revealed a north velocity error had been introduced into the flight loading tapes made for the MIT Phase II Experiment reference.

B. The engine automatically shut down at 31.6 seconds because of a low fuel discharge pressure condition; the pilot noted a low fuel line low pressure warning light. A turn back to Delamar was accomplished and jettison of propellants initiated. Final jettisoning occurred under favorable conditions with an aircraft angle of -9° (nose down) resulting in an estimated landing weight of 15,000 lbs. Other touchdown conditions were good, producing "light" landing loads of approximately 7500 pounds skid load. These loads correlate with bell crank loads of 31,073 lbs on the left side and 38,652 lbs on the right side; load limits are 48,800 lbs with an ultimate capability of 73,320 lbs. The touchdown point was long, and the aircraft ran off the lake for 265 feet. The slide out distance was 6397 feet with 6132 feet on the lake surface. The canopy was jettisoned by the pilot before the aircraft left the lake. Moderate damage was sustained by the canopy on contact with the lake surface. The aircraft velocity at the lake edge was 70-80 knots and the elapsed time for final off-the-lake deceleration was 5.8 seconds. Peak bell crank loads were experienced on a bump on the lake edge at 39,678 lbs left and 53,147 lbs right.

C. The aircraft was inspected on site and appeared to have sustained no serious landing gear or structural damage. The right hand fairing door was missing (having been blown off because of engine compartment pressure measured at 3 psig). A crack was noted in the engine fuel pump outlet scroll to explain the abrupt loss of fuel pressure. The B-52 pylon LN2 disconnect and three feet of hard line remained attached to the X-15, probably because of frozen moisture (since the LN2 disconnect was removed with normal effort). A secondary malfunction of the LN2 supply check valve was evident because the LN2 supply was depleted during landing or shortly afterward. Verification of suit vent supply and normal APU bearing temperatures after landing indicate no other problems were caused by the LN2 depletion.

D. The Micrometeorite experiment extended at some time during flight or during the decelerations after touchdown. The experiment switch was not moved from the "OFF" position, reference item I A.

E. The untested items which demonstrated satisfactory operation during the flight include:

1. The MLG uplock hook beefup operated normally during the gear cycle, however the gear was not subjected to large temperature differentials.

2. The flip-top elevator lid and closeout seal were in good condition, and cockpit pressure was normal.

3. The stick-kicker operated with reduced effectiveness, estimated at 5° up horizontal stabilizer. Some doubt exists concerning magnitude of the stick-kicker input because of opposing pilot inputs. The 600 psi service pressure was reduced by cold soak to 500 psi during the flight.

4. The new pilots panel layout was given approval and pilots comments were not unfavorable.

5. The "window shade" apparently helped with the sun glare problem during the rotation and the landing. The pilot did not retract the shade for landing.

6. The cockpit pressure regulation was excellent with good recovery response shown during the suit check. An exceptionally severe cold soak was demonstrated during the extended takeoff schedule with propellants serviced for 5:25 hours before takeoff.

7. For future reference, the on-board fuel hold time was 4:38 hours; the fuel temperature change recorded was from -49°F to -35°F at launch.

8. The Air Density experiment containing a radioactive isotope, tritium, was installed for this flight. Activities on the lake and during the recovery operation were without incident. The experiment total pressure port was covered with tape by the instrumentation technician after he arrived at the site. No further changes were made until the aircraft returned to the NASA hangar. During the aircraft inspections, the Air Density experiment was removed from the pod without the tape covering the sensing port. Dirt particles which had entered the experiment cavity during the landing over-run apparently eroded the radio-active material from the treated chamber. These dirt particles were dumped out of the experiment when the experiment was removed. When a potential problem was later defined, a post-contamination check failed to locate any residual contamination.

Approved by: Prepared by:

Perry V. Row Ronald S. Waite

X-15 Senior Project Engineer X-15 Project Engineer