Proceedings of the Accident Classification Committee regarding B-17G airplane, AAF No. 42-31257
The manner of performance of the crew in this accident is most commendable, since the majority of the crew escaped serious injury and the cause of the accident could be determined from knowledge gained from the remaining crew.
This B-17G was on a routine four-hour gunnery mission. The first two hours consisted of high altitude malfunction practice and the second two hours were to consist of camera gunnery at a lower altitude.
The pilot assembled the crew at 0600 for a complete briefing of the missions, explaining all steps and stages of the gunnery mission and mentioning all emergency procedures. The pilot definitely specified that each crew member would keep his parachute harness on at all times and would keep his parachute pack with him throughout the ship whenever he was required to change positions. The whole crew was thoroughly impressed with these instructions and abided by them throughout the mission.
They took off on their mission at approximately 0700. Everything was in order. The airplane was serviced with three hundred (300) pounds of oxygen. They climbed to twenty thousand (20,000) feet and remained at this altitude for approximately one and one-half (1-1/2) hours. The crew put on their oxygen masks between nine thousand (9000) and ten thousand (10,000) feet as instructed by the pilot. The mission at twenty thousand (20,000) feet was uneventful and after returning down to nine thousand (9000) feet, the crew was instructed to remove their oxygen masks and proceed with the camera mission after meeting the fighter plane at the designated rendezvous point.
The first student in the front section of the airplane had spent his film in the upper turret. While in the turret he took his parachute with him and placed it on the floor beside the turret. Nothing happened during his course of operation except that the interphone went out of commission in the turret. This student returned to the nose of the airplane and the second student took his position in the turret and loaded his film. He also took his parachute pack with him and placed it on the floor beside the turret. This student noticed that the interphone was out of commission, but the instructor ordered him to continue anyhow. By this time, the engineer had checked everything very carefully, reported to the pilot, and returned to the radio compartment to keep out of the way of the gunners.
After the second student had started tracking with the turret, he noticed it had suddenly stopped working. He tried to move the controls again, but they wouldn't move. Luckily it had stopped in the almost stowed position with the guns rearward, so he could easily get out. Just a split second after the turret had stopped, the student noticed a violent array of sparks flying around his legs, and without any further delay, he backed out of the turret and down into the forward tunnel, taking his parachute pack with him, beating out the fire on it which had been ignited by the sparks. By the time the student was in the nose, the cabin was filling rapidly with smoke and intense heat. The pilot and co-pilot stated that they saw a flame emerging from underneath the center of the turret, shooting toward the left side of the cockpit, similar to a strong blow torch or acetylene torch flame. It was a bluish or red flame. They stated that the heat was intense and the smoke had an acrid, irritating odor.
The co-pilot then went down into the nose of the airplane. The crew already had their parachutes on and upon his command, relayed from the pilot, and started bailing out. One student who had become frantic was crying out that someone had taken his parachute, and started grabbing violently at the parachutes of the other crew members,. He grabbed the co-pilot's parachute and pulled the rip cord, spilling the parachute. The co-pilot gathered it up in his arms, held the pilot chute in his hand and jumped out. It opened, but had been burned and ripped somewhat, which is probably the reason that the co-pilot was injured on landing.
The pilot had followed the co-pilot down into the nose and picked up the students parachute from the floor and handed it to him and them jumped himself. This student had put the parachute on upside down and followed the pilot out. His parachute opened and he landed uninjured.
In the rear of the airplane, the instructor noticed the smoke and started up through the bomb bay with a fire extinguisher, but realized it was useless because the fire and smoke were too intense. He heard someone shout, "bail out" and immediately returned to the radio compartment and closed the door behind him. By this time all but one in the rear of the airplane had their parachutes on and were ordered to bail out. One student in the rear of the airplane couldn't find his parachute and the instructor told him it was located in the radio room. The first man standing at the side door, was pushed out by the man behind him. The remaining crew stated that his parachute had opened. This man was never found by any searching party and it is believed that his parachute opened but that he may have been injured while landing in some inaccessible place and died of exposure and injuries. One man was found among the wreckage with is parachute on. This is the man who had to return to the radio compartment to get his parachute and probably was suffocated before he could get back to the escape door. Another man was found after he had walked out of the mountains for a distance of about fifteen (15) miles away from the scene of he accident. He received minor injuries.
The pilot and co-pilot had assembled eight (8) other men on a mesa and they proceeded to walk out of the mountains and were picked up by the searching party approximately thirty-six (36) hours after the accident.
An intensive searching party, working by reliefs, was organized by this field, equipped with ground to air communications. Also a posse organized by the deputy sheriff of Alamo, Lincoln County, Nevada, equipment with pack horses, aided in the search. It took four (4) days for a ground party to reach the scene of the accident.
It is the opinion of the Accident Classification Committee that this accident was due to a material failure, not charged to the operating or maintenance personnel in any way. The equipment that failed which caused the accident is described as follows: The Sperry turret of the B-17TG is furnish with oxygen from the ship's supply through a single tube from the left side of the airplane, across the top of the floor to the electrical junction box under the turret. The junction box is also located on the floor and the oxygen tube is subject to damage by being kicked or stamped upon. The oxygen line is led into the electrical junction box through a rubber grommet, and is protected by being covered with a rubber hose. The cables in the junction box are quite tightly packed together, especially where they leave the junction box to go into the slip rings. The hole though which the wires pass, together with the oxygen line, is not properly reamed, as is the general procedure of electrical installation. This leaves a sharp edge upon which insulation can be cut from motion of the airplane and motion of the turret.
The wires and oxygen supply line are in close contact with each other where they are led up into the slip rings. The slip rings, although designed to be held by a positioning lug inserted in a slot in the slip ring are in reality being held on part of the time, as the lug is a loose fit allowing several degrees of relative motion between the slip ring and the bars to which it is attached.
The conductors in the junction box are subjected to three hundred (300) amperes at twenty-four (24) volts for starting the turret, and the system is fused for one hundred and twenty (120) amperes. The continues load is approximately sixty (60) amperes.
The progressive steps leading up to the accident are as follows:
Approximately five (5) minutes before the fire became visible, the interphone in the upper turret failed. The interphone in other parts of the airplane were also reported to be inoperative. The interphone cables are also contained in the junction box along with the power cable and oxygen line.
It was decided to operate the turret without the interphone and a student proceed to do so.
While manipulating the turret the power failed and the turret could no longer respond to the controls. Simultaneously, there was a loud hissing noise from under the turret floor, and above the airplane floor, accompanied by a dense shower of sparks, such as made by a cutting torch when cutting steel.
The smoke developed into flame, which assumed a torch like shape, directed from the vicinity of the junction box to the left side of the airplane.
The flame was described as being from two (2) to four (4) inches in diameter and from sixteen (16) to twenty-four (24) inches long. The color at first was very bright yellow with a blue tip. It was accompanied by showers of sparks.
Great heat was developed, with clouds of light colored, acrid smoke which obscured the instrument panel and made outside vision impossible. Opening the co-pilot's window drew the smoke and heat forward and it was necessary to close the window.
Sufficient heat was developed to burn the ears and neck of the pilot and co-pilot, even though protected by armor plate behind the seats.
Later observation of the smoke and flame indicated that the color of the smoke had changed to black and the flames to red as more flammable materials, such as hydraulic fluid, and wooden flooring were ignited.
Before the fist man had left the nose section of the airplane, the fire had burned through the fuselage at a point ahead of the bomb bay and below the turret.
It is believed that this accident was caused by an electrical failure within the junction box or turret hose, the resultant heat of which burned through the oxygen supply line, which contained oxygen at two-hundred and fifty (250) pounds pressure per square inch. The fire thus being supported by four (4) bottles of oxygen, burned through the metal junction box and set fire to everything in the immediate vicinity. The torch like flame was probably produced by the burning gases being forced out of the junction box through some hole in the left side of the junction box.
RECOMMENDATIONS: It is recommended that the design of the Sperry upper turret be so modified that at no time will oxygen lines be carried through an electrical junction box, or in close proximity to electrical connectors.
I first learned about this accident from a brief mention in an old newspaper article. No specific location was given nor were any details of the accident stated. I later obtained a copy of the official crash report and learned more about the cause of the crash, but the report was vague with respect to location and really didn't offer any clues to finding the wrecked plane. With the general description given in the crash report, and with other information I had gathered, I decided the quickest way to locate the illusive plane was to make an aerial search by helicopter. After an exhaustive aerial search, flying up canyons and over mountains, all the pilot and I found was a drop tank off an F86!
Persistence finally paid off, while returning from a business trip I decided to detour into the area that I previously searched by helicopter. With a little luck and following up on a hunch, I ventured deep into the mountains. I hiked for about five or six miles, up and over several mountains. It was almost dark when I crested the top of another mountain, when there, out in the distance, low and behold, I spotted the B17!
I could see tiny fragments shining in the late afternoon sunlight. I scrambled across the rocky ledges, down one canyon and up the other side, when finally I reached the remains of the mighty Flying Fortress. At first I found only one of the massive R1820 radial engines, but as I climbed the hill I spotted two more and then the forth. At that point I felt certain I had finally located the B17.
There were oxygen bottles scattered all over the mountainside and fragments of aluminum; pieces of the fuselage, cowl flaps, wings, doors, and other parts. I even found an old canvas first aid bag containing several "Band-Aid" bandages in their original wrappers. An old radio, pieces and parts from the bombardiers compartment, some instruments and other miscellaneous hoses, pipes and fittings. Even the armored plates from the pilots' seat were there and all of the landing gear too.
As I sat on the mountainside, I looked out in the distance and could see a mesa; perhaps the one where the crew had landed some 54 years before. I could almost visualize the crew watching as the doomed airplane spiraled down and hit the mountainside and exploded into a giant fire ball. What an awesome experience! As the sun set on the horizon I took some photos and hastily departed, only taking memories and leaving behind a part of aviation history.
Return to top