During flight 3-14-24, the #1 APU experienced a completely failed pinion gear and the #2 APU had a badly worn pinion gear. Since then, numerous tests have been conducted at the APU test stand. These tests were made under various conditions of altitudes (up to 170,000 in an altitude chamber); oil level; types of oil used; pressurized gear cases; APU rotated in various positions. It was concluded from these tests that an APU can be operated at various altitudes without adverse effects by pressurizing the gear case.

B. Preston tube installed on forward fuselage approximately Station 50.

C. Vertical tail rake installed approximately water line 60.5.

D. Wing rakes installed on upper and lower left hand wing.

E. Lower vertical actuator and torque box removed.

F. Heat shield installed on lower fixed vertical in place of torque box.

G. Noise panel installed in place of panel #F-30.

H. Pilot's instrument panel replaced by a modified panel. This modification removed the lox bearing temperature indicator, and hydraulic temp indicator. It also changed the size of the chamber pressure and 2nd stage indicator and the shape of the roll rate indicator.

I. 35 mm camera installed alongside of the block spectrometer.

J. Nose gear door heat seal installed.

K. Pressurization system installed for Air Force physiological blood pressure system.

B. Installed forward manometer 1-12 cell for forward rake of the heat transfer instrumentation.

C. Modification of horizontal stabilizer CPT's to produce independent position indications for pitch and roll.

D. Installation and hook-up of boundary layer noise instrumentation, including Parsons tape recorder and associated signal conditioning and control boxes.

E. APU gear box pressure and vibration pick-ups installed and hooked up.

F. Wiring for aft 35mm camera installed and hooked up.

G. Lox bearing temperature installed on TM.

B. Engine S/N 111 installed and a ground run performed on March 30, 1963. Fire warning system was activated and caused a premature shutdown on second engine run. Another ground run was attempted on April 5, 1963, with an associated fuel leak from a cracked fuel pump.

C. Engine S/N 110 was installed and a run accomplished on April 10, 1963. Engine data looked good, but evidence of helium ingestion in the NH3 system was observed. The NH3 fill line was removed and new O-rings installed. A ground pump-run was performed on April 13, l963, which showed that the helium leak had been fixed.

D. Hydraulic oil samples showed evidence of contamination prior to mating. NAA Inspection Department informed NASA that the hydraulic samples sent down were out of specification. The hydraulic stand was changed and the aircraft's systems flushed. New samples were OK'd for flight.

B. Nose gear door damage. Considerable damage was sustained by premature opening of the nose gear close-out door at an altitude of approximately 55,000 ft and a velocity of 3400 ft/sec.

C. Main landing gear extended to max skid spread after roll out. The main struts were x-rayed; the bell cranks were dimensionally checked and dye checked. The oleo struts were checked for pressure servicing. No evidence of failure or servicing discrepancies were noted. The oleos were then sent to NAA for evaluation.

D. Tape recorder shut off when 15 ips was selected by the pilot. Post flight tests showed that a fast switching from 7 1/2 ips to 15 ips would cause a shutdown. A change in the switching sequence eliminated this problem.

E. Pitch vernier inoperative. The switching sequence is such that it can be left in the wrong position and the switch indicating differentially. A pre-launch check is now being contemplated.