Colorado

After a routine radio ramp check, Flight 629 taxied to runway 08R (80 degrees, right) and at 1844 the flight was in runup position where it was given ATC clearance for the flight to Portland, the first intended landing. The clearance, in part, included compulsory radio reports from the flight upon passing the Denver Omni and when climbing through 18,000 feet to its assigned flight altitude, 21,000 feet. Following takeoff the flight reported its "off time" to the company as 1852 and thereafter reported passing the Denver Omni at 1856. The latter communication was the last from the flight. About 1903 the Denver tower controllers saw two white lights, one brighter than the other, appear in the sky north-northwest of the airport and fall to the ground. Both lights were observed 30-45 seconds and seemed to fall with approximately the same speed. There was then a momentary flash originating at or near the ground which illuminated the base of the clouds, approximately 10,000 feet above. When the controllers observed the lights they initiated action to determine if any aircraft were in distress. Radio calls were made to all aircraft in the Denver area of responsibility and all except flight 629 were accounted for. It was soon learned that the flight had crashed and all 44 occupants had been killed. It was later confirmed that the disintegration of the aircraft in the air was caused by a bomb. Two weeks later, on November 15, investigators confirmed that an explosive device has been placed on board by John Gilbert Graham aged 23 who signed a US$ 37,500 life-insurance for his mother who was on board. Convicted guilty for murder and terrorism, he was sentenced to death penalty and executed on January 11, 1956.

Crashed in unknown circumstances two miles north of Calhan. Occupant fate unknown.

Few minutes after takeoff from Denver, bound for Kansas City, the twin engine aircraft hit the slope of a mountain located 8 miles northwest of Golden. The aircraft was destroyed and all 11 occupants were killed. For unknown reason, the crew was flying to the west straight on to the Rocky Mountains instead to the east to Kansas City.

United Air Lines operates a Flight Training Center at Denver, Colorado, to train applicants for first officer positions with the company. The crew of United Trainer 16 consisted of Senior First Officer Jordan D. Kocher, who had been designated by United Air Lines as captain and instructor, and Trainee First Officers Laurence G. Wilson and Wayne C. Moen. The flight departed Stapleton Airfield at 0655LT. The 0628 weather conditions, upon which the crew had been briefed, were ceiling measured 15,000 feet, visibility 25 miles, and wind northwest 14 knots Ceiling and visibility were unlimited at the time of the accident, with the wind northwest 16 knots. No radio contacts were made by United Trainer 16 after reporting departure time. It was cleared for a training flight of four hours’ duration within a 25-mile radius of Denver Captain Kocher occupied the left pilot’s seat at takeoff. Upon departure, the aircraft load, in addition to the crew, was 820 gallons of gasoline, full oil tanks, and 650 pounds of sand ballast tied down in the rear baggage pit. The load was properly distributed with relation to the aircraft’s center of gravity, and the 22,910-pound gross weight at takeoff was within allowable limits. Witnesses reported that at between 0720 and 0725 the aircraft was seen to stall, enter a spin, and strike the ground in a diving attitude before recovery was effected.

The crew was performing a liaison flight when an engine failed en route. The captain decided to divert to Lowry AFB in Denver for a safe landing. Unfortunately, on final approach, the heavy bomber stalled and smashed in flames in a residential area located few hundred yards short of runway threshold. The aircraft disintegrated on impact and was destroyed by a post crash fire. Five houses were damaged and four others were destroyed. On ground, six people were injured as well as six crew members. Eight others were killed in the crash.
Crew:
Cpt James W. Shanks, pilot,
1st Lt Robert H. Snure, copilot,
T/Sgt Robert F. Jarvis, gunnery instructor, †
T/Sgt Herbert Oeser, gunnery instructor, †
Cpl Richard P. Yukob, gunnery instructor, †
Pfc James E. Snyder, gunnery instructor, †
Pfc Ronald W. Wiersma, gunnery, †
Pfc William J. Ablondi, gunnery, †
Pfc Baxter Srber, gunnery, †
Pfc John R. Servic, gunnery. †
S/Sgt William A. Zippel,
Cpl Ray E. Widner,
Pfc Teddy D. Allen,
Pfc Joe D. Wiggins.

Flight 610 of June 29, 1951, originated in San Francisco, California, and was scheduled to Chicago, Illinois, with en route stops, among which were Oakland, California, Salt Lake City, Utah, and Denver, Colorado. The crew consisted of Captain J R Appleby, First Officer H G Tower, Flight Engineer A T Petrovitch, and Stewardesses C J Baymond and F M Smith. The flight departed San Francisco on schedule at 1915 and after stopping at Oakland proceeded to Salt Lake City, arriving there at 2324. It departed Salt Lake City at 0011, June 30, 1951, 26 minutes behind schedule due to the reloading of bulky cargo At the time of departure the aircraft weighed 78,597 pounds, which was within the certificated gross take-off weight of 79,380 pounds, the load was properly distributed with respect to the center of gravity. There were five crew members, forty-four adult passengers and one infant on board. The approved flight clearance indicated an IFR flight, via Bed Airway 49, Green Airway 3, and Amber Airway 3, to Denver at a cruising altitude of 15,000 feet, with Omaha, Nebraska, designated as the alternate airport. The flight proceeded in a routine manner and at 0104 reported over Rock Springs, Wyoming, at 15,000 feet, estimating its arrival over Cheyeme, Wyoming, at 0147 and over Denver at 0207 2 Forty-three minutes later, at 0147, the flight reported having passed the Silver Crown fan marker (located 12 miles west of Cheyenne) and requested a lower altitude Accordingly, a new clearance was immediately issued-"ARTC clears United 610 to Dupont intersection, 3 descend to 8500 feet immediately after passing Cheyenne, maintain 8500 feet, no delay expected, contact approach control over Dacono "4 This clearance was acknowledged and the flight reported that it was over Cheyenne at 0147, at 15,000 feet and was now starting to descend. The Denver altimeter setting was then given the flight as being 30 19 inches. Nine minutes later, at 0156, the flight reported reaching its assigned altitude of 8,500 feet No further communication was received from the flight. At 0200, the Denver Control Tower requested the company radio operator to advise the flight to call approach control Repeated calls were made without an answer. It was later determined that Flight 610 had crashed on a mountain (Mt Crystal) 18 miles west-southwest of Fort Collins, Colorado. All 50 occupants were killed.

The crew performed their “before takeoff check", found all components of the aircraft to operate normally, and then, at 0329, rolled onto the runway for takeoff. From the tower, the aircraft appeared to accelerate slowly and to take an excessively long period of time to become airborne. The pilots stated that the engines operated normally, developing 45-inch hg. of manifold pressure and 2700 RPH (revolutions per minute), but air speed increased slowly. Between 90 and 100 miles per hour, and just before the end of the runway was reached, the aircraft was pulled off the runway by Captain Robins as he applied back pressure on the control column. After take-off, the highest air speed attained was between 100 and 105 miles per hour. The landing gear, control was placed in the “up” position,when the flight became airborne, and a climb was made to about 100 feet. During the climb, the aircraft shuddered severely. Altitude was lost, and the aircraft struck an obstruction light on the top of a 40-foot electric light pole which was 1,910 feet south of the end of the runway. The aircraft struck three more pole, then touched ground and skidded for 350 feet. It came to a full stop 2,791 feet from the south end, and in line Runway 17. The crash landing was made in an alley way of a residential district located between Stapleton Air Field and the Lowry Air Force Base, which is located 1-1/4 miles south of Stapleton. In addition to striking the electric light poles, the aircraft knocked down several fences, a small tool shed, and collided into two parked automobiles. Crash and fire equipment which was dispatched from both the Stapleton and Lowry Airports and the city of Denver arrived promptly. Partly as a result of their precautionary action, no fire occurred.

Crashed in Lowry AFB while landing in poor weather conditions. At least one crew member was killed in the accident.

On a night approach to Lowry AFB, the twin engine aircraft crashed in flames onto a military installation located 7 miles northeast of the airbase. Both crew members were killed.

The aircraft departed Denver at 1602 for Grand Junction. The crew, all employees of the Civil Aeronautics Administration, consisted of Fred L. Snavely, pilot; Warren L. Lungstrum, copilot; and Ross C. Brown, observer. Over the route to Grand Junction a check was to be made by these men of the VHF (very high frequency) airway facilities to determine whether they were operating normally. According to the flight plan, the flight was to proceed over Red Airway 6 at an air speed of 150 mph. Though only 2 hours were required for the trip, 8 hours supply of fuel was carried. Information supplied to Copilot Lungstrum at the Denver United States Weather Bureau Office was to the effect that clear weather conditions existed generally over the intended route. Over Fraser, Colorado, located approximately 50 miles west northwest of Denver, however, broken clouds were reported. Since this layer of clouds was only 2,000 feet in depth, with tops at 13,500 feet above sea level, it appeared that a cruising altitude of 14,000 or 15,000 feet would be high enough for the flight. Winds at that altitude were from the northwest at 50 mph. Weather Bureau personnel advised that these winds would result in considerable turbulence. Take-off was accomplished at 1602. Twenty-two minutes later, at 1624, the CAA communication station at Denver received a position report from the flight that it was at an altitude of 14,500 feet, 500 feet over the top of clouds, and 20 miles west of Denver. The flight also reported that they were experiencing severe turbulence. Since the flight plan specified that the trip would be made in accordance with visual flight rules, and since the position report indicated that the aircraft was being flown over the top of clouds, the flight was requested at the termination of their 1624 position to verify whether they were actually proceeding in accordance with visual flight rules. A response in the affirmative was received. About one minute after the 1624 report the CAA communicator at Cheyenne, Wyoming, called NC206 and asked for a check of his station’s radio transmission. NC206 responded, “Read Cheyenne Radio loud and clear.” The communicator then asked for a position report from NC206, and the flight replied, “We are approximately. . . .” The remainder of this message, received shortly after 1625, was garbled and faded. The Cheyenne communicator attempted to contact the flight again but was unable to do so. Since interference to radio transmission could have resulted from the mountain ranges between Cheyenne and the aircraft, and since the Cheyenne communicator had overheard the report of severe turbulence, he presumed that the crew was completely occupied in flying the aircraft, and that either they had not heard the last transmission or were too busy at the time to acknowledge. Accordingly, he placed no significance on the failure of the flight to reply. A request had previously been made by the communication station at Eagle, Colorado, for the flight to check the radio transmission of that station. Since Eagle Radio did not receive any calls from NC206, the station called the flight at 1645. No reply was received. Repeated calls were made by the communicator at Eagle on all available frequencies at three-minute intervals until 1735. Then the station requested information concerning the flight from Grand Junction Radio, but neither Grand Junction Radio nor any other radio station on the route had received a call from NC206 since 1625. At 1825, 23 minutes after the estimated arrival time of NC206 at Grand Junction, an emergency was declared.