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The Aircraft Accident Investigation Board in its final report issued a finding of facts:

“a.  The mission was an authorized local instrument training flight in connection with the training of students in class 48–B.

b.  Weather at the time of the accident was broken to overcast clouds with ceilings of 1500 feet, visibility of 12 miles.  The tops of the overcast were generally 3500 to 400 feet.

c.  Parts of the aircraft were scattered over an area of approximately one and one quarter miles.  The general flight path appeared to have been from north to south, and judging from scars on the trees within the crash area, the TB-2t5’s descent was near vertical, although it crashed in a flat attitude.

d.  The right wing tip, right rudder, right fin and horizontal stabilizer were approximately 1 1/2 miles north of the main section of the wreckage.  The two landing gear nacelle doors,k the left wing from the landing light outboard, minus the aileron and flap, were found 3/4 miles north of the main section of the wreckage.

e.  Skin had been pulled over the heads of all rivets on the wings, and control surfaces, and the skin on the wings was rolled from the trailing edge toward the leading edges of the wings.

f.  The throttles were in a closed position and the directional gyro was caged.  The artificial horizon was in such condition that it was impossible to determine whether or not it was caged.

g.  The propellers were not feathered and there was no indication of fire or explosion.  The aircraft did not burn upon impact.

h.  Three of the bodies were thrown approximately fifteen feet from the wreckage and it was impossible to determine what position each crew member was occupying at the time of the crash.

i.  On 22 April, Lt. Thomas had given basic instrument checks to Cadets Hillman and Connor.  Cadet Connor passed the check; however, Cadet Hillman was given an unsatisfactory grade.  Part of his failing the check was due to his inability to recover from unusual positions which the instructor described as ‘he made no effort to stop the airspeed from changing rapidly.  He couldn’t realize the altimeter spinning like a wheel.’

j.  On 23 April, Lt. Thomas listed his mission as T-15 (instrument check or practice) with the intent of giving additional instruction to Cadet Hillman.

k.  Aviation Cadet Harris, Lt. Thomas’s third student who was not scheduled for the flight on 23 April, testified that he was on the flight on 22 April when Cadet Hillman failed his basic instrument check.  Cadet Harris also stated that Lt. Thomas had on one occasion placed the aircraft in a vertical bank which exceeded 90 degrees when he turned the aircraft over to Cadet Hillman for recovery on partial panel, and that Cadet Hillman’s recoveries had been somewhat abrupt on the previous day.

l.  It was the policy of Lt. Thomas to cage the gyro instruments when giving unusual positions to students.

m.  The B-25 Pilot’s Manual list the maximum diving speed as 34 MPH indicated.”

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The Aircraft Accident Investigation Board then briefly discussed the reasoning used in arriving at its conclusion:

“a.  The pulled rivets, widely scattered wreckage, and the manner or altitude in which the TB-25 crashed clearly indicates structural failure.  Since there were no indications of fire, the possibility of fire and explosion was discounted.  The pilot had reported a thundershower west of Shreveport when he contacted Shreveport radio for a change of flight plan at 0844; however, no thundershowers were reported in weather sequences and there was not a thundershower in progress at the time the TB-25 crashed.

b.  The caged gyro, the grade-slip of Cadet Hillman for the previous day, and the testimony of Cadet Harris, substantiate the theory that Lt. Thomas, while flying 500 on top of the stratus cloud deck, placed Cadet Hillman in an unusual position and the cadet allowed the aircraft to build up sufficient speed to exceed its designed limitations while attempting to recover.  That the cadet stalled the aircraft and got into an unintentional spin is also a possibility.  If the aircraft entered the undercast in an abnormal attitude, it would be extremely difficult for the instructor pilot to recover with the gyro caged.

c.  This headquarters published in Special Accident Report No. 1, Vol. XV, titled ‘Structural Failures in B-25s’ ten previous accidents that very closely paralleled this accident.  The B-25 is stressed for a plus 3.67 ‘G’ for pull outs and minus 2.00 ‘G’ push over.”

The Board then stated its final conclusion:

“It is concluded that the cause of this accident was the pilot’s allowing the student to get into such a position or attitude so that the designed limitations of the aircraft were exceeded during recovery, resulting in structural failure of the aircraft.”

The last paragraph of the Board’s report is an especially poignant one:

“STATEMENT OF REBUTTAL:

a.  Inasmuch as the crew was killed in the crash, a statement of rebuttal regarding pilot error was not applicable.”

Because the Air Force found pilot error to be the basic cause of the Canfield plane crash of 1948, I have chosen to use pseudonyms instead of actual names in referring to the deceased crew.

The pilot-instructor was LT. THOMAS.  He became a navigator on January 23, 1943, and flew 50 combat missions in the southwest Pacific during World War II.  He became a pilot on August 27, 1946.  He was issued a white instrument card on August 13, 1947.

There were two cadet-student pilots on the plane.  CADET HILLMAN and CADET CONNOR.  The crew chief on the plane was an enlisted man, SSGT HERMAN.

And, finally, there was a third person involved in the investigation of the crash, CADET HARRIS, who was not on the plane on the day it crashed, but who had flown with Lt. Thomas on the previous day, and who gave crucial testimony as to what might have occurred at the time of the crash.  Cadet Harris gave sworn testimony to the investigation board at Barksdale on April 27, 1948, four days after the crash. Excerpts of the testimony of Cadet Harris follow:

“Q.  What date did your last flight with Lt. Thomas as instructor occur?

A.  22 April.

Q.  Do you recall what the mission was on that day, transition or instrument training?

A.  Instrument training.

Q.  Did Lt. Thomas ever place students in abnormal or violent unusual positions?

A.  He once placed Cadet Hillman in an exaggerated position in which he had more than a 90 degree bank at the time he gave it to the student to recover.

Q.  On basic instruments, including unusual positions, did Lt. Thomas usually cage the gyro instrument or did he cover [it] then with colored glass?

A.  He usually covered them with a map he carried in his pocket except during unusual positions.  He usually caged [it] then during unusual positions.

Q.  From the grade slip I noticed that Cadet Hillman had given an unsatisfactory ride on  the 22 of April, were you along on that flight?

A.  Yes, I was.

Q.  On his recovery from unusual positions, did he seem abrupt on recoveries?

A.  Somewhat, yes.

Q.  Is there anything else you would like to add that you think would be of interest in the investigation?

A.  Before the flight that morning, Lt. Thomas had talked to Cadet Hillman quite a bit about instrument rides and also mentioned his landing the day before.

Q.  Did you observe Lt. Thomas and Cadet Hillman entering the airplane that morning?

A.  No, I did not.

Q.  In other words, you don’t know if he was actually flying the airplane at that time?

A.  No, I wouldn’t.”

(To be continued.)

The narrative from the report of the Aircraft Accident Investigation Board from Barksdale Air Force Base is set forth below:

“This aircraft took off from Barksdale AFB, Louisiana at approximately 0830 CST.  Aircraft had cleared on a local VFR clearance.  The mission was instrument instruction to two (2) Aviation Cadets assigned to the Air Force Advanced Pilot School.

At 0844 CST the pilot contacted Shreveport Radio and requested to change to IFR, asking for 500–on-top.  Pilot stated that he was a local B-25 and requested to do instrument practice above the cloud deck for 2 hours and 45 minutes.

At 0849 CST Shreveport Radio cleared the aircraft to climb to 500–on-top under visual flight rules, to report reaching 500–on-top and to request further clearance before descending.  He was cleared to fly all quadrants of the Shreveport and Barksdale ranges.

At 0852 CST pilot reported at 500–on-top giving his altitude as 4000 feet with tops of clouds at 3000–3500 feet and 4000 feet in spots.  Pilot reported a thunderstorm to the west with tops estimated at 10,000 feet.

At approximately 0950 CST witnesses saw the airplane falling at a rapid rate of descent.  Pieces were seen flying from the aircraft.  The aircraft crashed in a densely wooded area 48 miles north of Barksdale AFB.  An examination of the wreckage revealed that both wings outboard of the engines and entire empennage had fallen from the aircraft and were scattered over an area one (1) mile north of the crash.  Examination of the wings and tail assembly revealed that parts were evidently blown off.  There was no indication of fire or explosion.  The bodies of the four (4) crew members were found at the wreckage.  There had been no attempt to “bail out.”

There were no thunderstorms reported in the area where the airplane crashed. 

Investigation was hampered by the lack of any qualified witnesses to the accident.

One of the students aboard had failed a basic instrument check the day before and had experienced difficulty recovering from unusual positions.

The Aircraft Accident Investigation Board was unable to determine just who was sitting in the pilot’s and co-pilot’s seat.

CONTRIBUTING CAUSE FACTORS:  The exact cause of this accident is undetermined but is believed to have been caused by structural failure when the design limits of the airplane were exceeded.  The Accident Board is of the opinion that the instructor was giving unusual positions to the student and the aircraft entered the cloud deck.  It is believed that the aircraft built up a high rate of speed and during the recovery the design limits were exceeded.

RECOMMENDATIONS:  That the diving speed of B-25 type aircraft be limited to 250 miles per hour.  That all unusual positions be given at an altitude of at least 7000 feet above the ground and at least 3000 feet above any clouds if flying above a cloud deck.  That amber shields be used to cover gyro instruments during practice instead of caging the instruments.”

(To be continued.)