Crash of a Learjet 25B in Briggsdale: 4 killed

Date & Time: Aug 31, 1974 at 1250 LT
Type of aircraft:
Registration:
N366AA
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Denver - Denver
MSN:
25-151
YOM:
1974
Crew on board:
4
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
4
Captain / Total flying hours:
9323
Captain / Total hours on type:
161.00
Circumstances:
The crew (an instructor and three student pilots) departed Denver Airport in the morning for a local training flight. While cruising at an altitude of 17,400 feet, the instructor decided to introduce a runaway trim emergency to the student pilot who was on his 4th lesson on type of aircraft. The airplane entered a 20-40° nose-down attitude then crashed in a huge explosion in a field. The aircraft was totally destroyed and all four occupants were killed.
Probable cause:
Uncontrolled descent after the crew was unable to retrim the aircraft for undetermined reason. Unusual attitude practice with full nose down trim.
Final Report:

Crash of a Rockwell Sabreliner 40 in Midland: 2 killed

Date & Time: Jan 4, 1974 at 1924 LT
Type of aircraft:
Registration:
N34W
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Midland - Denver
MSN:
282-47
YOM:
1965
Location:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
15367
Captain / Total hours on type:
2770.00
Circumstances:
Shortly after takeoff from Midland Airport, while in initial climb by night, the airplane entered a nose-down attitude then crashed in a huge explosion few miles from the airfield. The airplane disintegrated on impact and both pilots were killed.
Probable cause:
Uncontrolled descent during initial climb for undetermined reason. Entered a high speed dive and crashed. Near total destruction limited the scope and decisiveness of investigations.
Final Report:

Crash of a Rockwell Sabreliner 60 in Montrose: 2 killed

Date & Time: Apr 13, 1973 at 1635 LT
Type of aircraft:
Operator:
Registration:
N743R
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Los Angeles - Montrose - Denver
MSN:
306-11
YOM:
1968
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
10000
Captain / Total hours on type:
84.00
Aircraft flight hours:
2372
Circumstances:
After takeoff from Montrose Airport, while climbing to an altitude of 1,000 feet, the airplane banked left to an angle of 55° then stalled and crashed in a huge explosion. The aircraft was destroyed by impact forces and a post crash fire and both pilots were killed.
Probable cause:
Loss of control during initial climb after the left engine thrust reverser deployed. The following factors were reported:
- Improper operations of powerplant,
- The pilot-in-command failed to follow the approved procedures,
- Improper emergency procedures,
- Unwanted thrust reversal,
- Continued operations of left engine at climb power after unwanted in-flight deployment of the left engine thrust reverser.
Final Report:

Crash of a Rockwell Aero Commander 680V in Aspen: 8 killed

Date & Time: Jan 22, 1970 at 0806 LT
Operator:
Registration:
N6359U
Survivors:
No
Schedule:
Denver - Aspen
MSN:
680-1536-4
YOM:
1965
Crew on board:
1
Crew fatalities:
Pax on board:
7
Pax fatalities:
Other fatalities:
Total fatalities:
8
Captain / Total flying hours:
5865
Captain / Total hours on type:
525.00
Circumstances:
On final approach to Aspen-Pitkin County-Sardy Field by night and marginal weather conditions, the pilot get troubled by the presence of frost on the windshield and failed to realize his altitude was insufficient. The airplane struck the slope of a mountain located few miles short of runway and was destroyed upon impact. All eight occupants were killed.
Probable cause:
Controlled collision with ground caused by the combination of the following factors:
- The pilot-in-command failed to follow the approved procedures and directives,
- Failure to provide adequate directives in manual equipment on par of the operational supervisory personnel,
- High obstructions,
- Accumulation of ice on windshield,
- The pilot-in-command failed to use or incorrectly used miscellaneous equipment such as windshield anti-icing and de-icing systems,
- Icing conditions including sleet and freezing rain,
- The pilot did not follow the company informal go-around procedures,
- There were no go-around procedures in the company operations manual,
- Mountain obscured by ice on windshield.
Final Report:

Crash of a Convair CV-240-12 in Aspen

Date & Time: Jan 17, 1970 at 0900 LT
Type of aircraft:
Operator:
Registration:
N270L
Survivors:
Yes
Schedule:
Denver - Aspen
MSN:
157
YOM:
1949
Crew on board:
3
Crew fatalities:
Pax on board:
24
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
9700
Captain / Total hours on type:
41.00
Circumstances:
Following an uneventful flight from Denver, the aircraft belly landed at Aspen-Pitkin County-Sardy Field Airport. It slid on the runway for several dozen yards before coming to rest. All 27 occupants were evacuated safely and the aircraft was damaged beyond repair.
Probable cause:
Wheels-up landing caused by a crew error. The following factors were considered as contributing:
- The pilot-in-command failed to extend the landing gear on approach,
- The crew failed to use the approach checklist,
- Failure of the landing gear warning and indicating components,
- Inadequate maintenance and inspection on part of the maintenance personnel,
- The gear warning horn was improperly set.
Final Report:

Crash of a Boeing 727-22 in Salt Lake City: 43 killed

Date & Time: Nov 11, 1965 at 1752 LT
Type of aircraft:
Operator:
Registration:
N7030U
Survivors:
Yes
Schedule:
New York – Cleveland – Chicago – Denver – Salt Lake City – San Francisco
MSN:
18322
YOM:
1965
Flight number:
UA227
Crew on board:
6
Crew fatalities:
Pax on board:
85
Pax fatalities:
Other fatalities:
Total fatalities:
43
Captain / Total flying hours:
17743
Captain / Total hours on type:
334.00
Copilot / Total flying hours:
6074
Copilot / Total hours on type:
84
Aircraft flight hours:
1781
Circumstances:
Flight 227 took off from New York-LaGuardia (LGA) for a flight to San Francisco (SFO) via Cleveland (CLE), Chicago (MDW), Denver (DEN) and Salt Lake City (SLC). The aircraft took off from Denver at 16:54 and climbed to its assigned cruising altitude of FL310. At 17:38 flight 227 began its descent for Salt Lake City. The flight proceeded in accordance with radar vectors. After a radar handoff to Salt Lake City Approach Control new clearance altitudes were given. At 17:47 the approach controller advised, "United seventy twenty seven ... five miles south of Riverton Fan Marker coming on localizer course cleared for ILS runway three four left approach." The pilot replied "Okay we're slowed to two fifty (Knots) and we're at ten (10,000 feet) we have the runway in sight now, we'll cancel and standby with you for traffic." Control of the flight was transferred to the tower and at 17:49:40 landing clearance was issued. The aircraft crossed the outer marker over 2,000 fee & above the ILS glide slope. The rate of descent during the final approach exceeded 2,000 ft/min, approximately three times the United Air Lines recommended rate of descent for landing approaches. The first officer attempted to apply power but the captain stopped him. Power was then applied too late to arrest the rate of descent. The airplane touched down 335 feet short of the threshold of runway 34L. The right and left main landing gear began to separate and the airplane slid onto the runway. Severe upward and rearward impact forces from the right main Landing gear assembly produced a large impact hole and ruptured fuel lines and the no. 3 generator leads between fuselage station 1030 and 1130 on the right side. The fuel was ignited by sparks from the fuselage scraping on the runway and/or the severed generator leads. 13 passengers were uninjured while 35 people were wounded. 43 other occupants were killed.
Probable cause:
The Board determines the probable cause of this accident was the failure of the Captain to take timely action to arrest an excessive descent rate during the landing approach.
Final Report:

Crash of a Lockheed L-1049H Super Constellation in Chicago: 11 killed

Date & Time: Nov 24, 1959 at 0535 LT
Operator:
Registration:
N102R
Flight Phase:
Flight Type:
Survivors:
No
Site:
Schedule:
Chicago – Denver – Los Angeles
MSN:
4824
YOM:
1957
Flight number:
TW595
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
11
Captain / Total flying hours:
12467
Captain / Total hours on type:
1670.00
Copilot / Total flying hours:
6285
Copilot / Total hours on type:
3919
Aircraft flight hours:
3432
Circumstances:
Flight 595, loaded with cargo, took off on runway 31L of Midway at approximately 0531LT bound for Los Angles, California. As the aircraft began a left turn, the crew notified Midway Tower they had received a fire warning on the No. 2 engine and had shut it down. They also informed the tower the flight would return and land. The aircraft proceeded in a continuing left turn around the airport in an elliptical pattern and below the clouds which were based at an altitude of 500 to 600 feet. In the turn to final approach to runway 31 the aircraft banked in excess of 45 degrees during which it developed an excessive rate of sink. When the aircraft reached the tops of the trees its wings were nearly level and its nose was raised in a climbing attitude; however, the descent continued. The wing flaps were being retracted during the last 5 to 10 seconds of the final descent and were found to be symmetrically extended at 24 percent upon impact. The plane crashed into a residential area about one-fourth of a mile southeast of Midway Airport, Chicago, Illinois, killing all persons aboard, demolishing the aircraft, and fatally injuring eight persons on the ground.
Probable cause:
The Board determines the probable cause of this accident to be the maneuvering of the aircraft in a manner that caused it to develop an excessive rate of sink while in the turn to final approach.
Final Report:

Crash of a Douglas DC-7 near Las Vegas: 47 killed

Date & Time: Apr 21, 1958 at 0830 LT
Type of aircraft:
Operator:
Registration:
N6328C
Flight Phase:
Survivors:
No
Site:
Schedule:
Los Angeles – Denver – New York
MSN:
45142
YOM:
1956
Flight number:
UA736
Crew on board:
5
Crew fatalities:
Pax on board:
42
Pax fatalities:
Other fatalities:
Total fatalities:
47
Circumstances:
United Airlines Flight 736 departed Los Angeles International Airport at 0737 hours Pacific standard time with 42 passengers and 5 crew aboard. It was a scheduled passenger flight to New York, which was proceeding normally in accordance with an IFR flight plan along Victor Airway 16 to Ontario, California, and Victor Airway 8 to Denver. The aircraft was cleared to a cruising altitude of 21 000 ft msl and advised to climb in VFR weather conditions. At 0735 the flight reported to Aeronautical Radio that it was over Ontario at 12 000 ft and was climbing in VFR conditions. Then at 081 1 it reported over Daggett at its cruising altitude of 21 000 ft and estimated that it would reach Las Vegas (omni range station) at 0831, This was the last position report made by the flight. At approximately 0745 hours that morning F-100F, 56-3755, took off from Nellis Air Force Base, Las Vegas, Nevada on an instrument training flight carrying an instructor and a trainee pilot. The flight was in accordance with a VFR local flight plan filed with Nellis Operations and the local traffic control tower. At approximately 0823, 755 called Nellis VFR Control and reported that it was "inbound on KRAM" ( a local commercial radio broadcast station). The flight requested an altitude assignment from which it would conduct a simulated ADF instrument jet penetration utilizing KRAM. The VFR controller assigned 755, 28 000 ft and advised it to report over the radio station. At approximately 0828, the flight reported that it was over KRAM requesting a penetration. The VFR controller cleared it for an immediate penetration and requested that it report the penetration turn. 755 then reported leaving 28 000 ft. There were no &her reports from the flight in connection with this procedure. At 0830 the offices of Aeronautical Radio at Los Angeles, Denver and Salt Lake City heard an emergency message from the United flight.. . . . " United 736, Mayday, midair collision, over Las Vegas. " At the same time, as nearly as can be determined, there was an unrecorded emergency transmission from the F-1 00F. This message was heard by the VFR controller and by the two pilots of another F-100F. All were agreed that the first portion of the emergency transmission was "Mayday, Mayday, this is 755. " The last part of the message was either, "We've had a flameout" or 'We're bailing out." The aircraft collided at 21 000 ft over a position later determined to be about 9 miles southwest of the Las Vegas VOR station, on Victor Airway 8, approximately 1-3/4 miles to the right (southeast) of the centerline. Both aircraft fell out of control and crashed killing the 47 persons on board the DC-7 and both pilots of the F-100F.
Probable cause:
The probable cause of this collision was a high rate of near head-on closure at high altitude; human and cockpit limitations; and the failure of Nellis Air Force Base and the Civil Aeronautics Administration to take every measure to reduce a known collision exposure.
Final Report:

Crash of a Douglas DC-6B near Longmont: 44 killed

Date & Time: Nov 1, 1955 at 1903 LT
Type of aircraft:
Operator:
Registration:
N37559
Flight Phase:
Survivors:
No
Schedule:
LaGuardia – Chicago – Denver – Portland – Seattle
MSN:
43538
YOM:
1952
Flight number:
UA629
Crew on board:
5
Crew fatalities:
Pax on board:
39
Pax fatalities:
Other fatalities:
Total fatalities:
44
Captain / Total flying hours:
10086
Captain / Total hours on type:
703.00
Copilot / Total flying hours:
3578
Copilot / Total hours on type:
1062
Aircraft flight hours:
11949
Circumstances:
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.
Probable cause:
The Board determines that the probable cause of this accident was the disintegrating force of a dynamite bomb explosion which occurred in the number 4 baggage compartment. The following findings were reported:
- At 1903, eleven minutes after departure, an in-flight disintegrating explosion occurred aboard Flight 629,
- The aircraft was climbing normally and was on course when the explosion occurred,
- Physical evidence showed conclusively the explosion took place in the number 4 baggage compartment of the aircraft,
- The violence of the explosion and the physical evidence proved the explosion was not caused by any system or component of the aircraft,
- Physical evidence at the scene and laboratory tests confirmed that the explosive material was dynamite, in the form of a bomb,
- There was no evidence found to indicate malfunction or failure of the aircraft or its components prior to the explosion.
Final Report:

Crash of a Douglas DC-4 on Medicine Bow Peak: 66 killed

Date & Time: Oct 6, 1955 at 0726 LT
Type of aircraft:
Operator:
Registration:
N30062
Flight Phase:
Survivors:
No
Site:
Schedule:
New York – Chicago – Denver – Salt Lake City – San Francisco
MSN:
18389
YOM:
1944
Flight number:
UA409
Crew on board:
3
Crew fatalities:
Pax on board:
63
Pax fatalities:
Other fatalities:
Total fatalities:
66
Captain / Total flying hours:
9807
Captain / Total hours on type:
2289.00
Copilot / Total flying hours:
2418
Copilot / Total hours on type:
343
Aircraft flight hours:
28755
Circumstances:
Flight 409 originated at New York, New York, on October 5, 1955, destination San Francisco, California, with intermediate stops including Chicago, Illinois, Denver, Colorado, and Salt Lake City, Utah. The trip to Denver was routine except for traffic delays, caused principally by weather, and the flight arrived there at 0551, October 6, one hour and 11 minutes late. Routine crew changes were made at Chicago and Denver, the last crew consisting of 'Captain Clinton C. Cooks, Jr., First Officer Ralph D. Salisbury, Jr., and Stewardess Patricia D. Shuttleworth. No discrepancies were reported by the former crew and none were found at Denver. While at Denver the aircraft was refueled to a total of 1,000 gallons of gasoline. Prior to departure Captain Cooke was briefed by the company's dispatcher on the en route weather, based on both U. S. Weather Bureau sequence reports and forecasts and the company meteorologist's forecasts and analysis. Following this briefing the flight me dispatched to Salt Lake City via airways V-4, V-118, V-6, and V-32, to cruise at 10,000 feet, and to fly in accordance with Visual Right Rules (VFR). The estimated time en route was two hours and 33 minutes. The only obligatory reporting point along the route was Rock Springs, Wyoming. The flight departed Denver at 0633, with 63 passengers, including two infants. At takeoff, the gross weight of the aircraft was 64,147 pounds, 653 pounds under the allowable weight of 64,800 pounds; an error of 100 pounds in excess of the allowable rear baggage compartment weight 2 was made in loading. Flight 409 reported its time off to the company and this was the last known radio contact with the flight. When the flight failed to report at Rock Springs at 0811, its estimated reporting time, repeated efforts were wade to establish radio contact with it. These were unsuccessful and the company then declared an emergency. A widespread search was immediately coordinated by Air Search and Rescue, which included the Wyoming Air National Guard, the Civil Air Patrol, and United Air Lines. At approximately 1140 the same day the wreckage was sighted near Medicine Bow Peak, 33 miles west of Laramie, Wyoming. The Laramie weather at 0728 was; Scattered clouds, 5,500 feet; visibility 40 miles; wind west-northwest 13 knots; snow showers of unknown intensity over the mountains. The aircraft struck the almost vertical rock cliff of the east slope of Medicine Bow Peak (elevation 12,005 feet) located in the Medicine Bow Mountains. The crash occurred at an elevation of 11,570 feet, 60 feet below the top of that portion of the mountain directly above it. Two large smudge marks were apparent on the face of the mountain. In these marks were four scars, evenly spaced and in a horizontal line, the result of the engines and propellers of the aircraft striking the cliff. At impact the aircraft disintegrated and the wreckage me strewn over a wide area. Some parts were thrown to the mountain top above the crash site, others rested on ledges at various levels, and the remainder fell to the elope below. All 66 occupants have been killed.
Probable cause:
The Board determines that the probable cause of this accident was the action of the pilot in deviating from the planned route for reasons unknown. The following findings were reported:
- The weather along the prescribed route was good and the aircraft could have been flown safely at an altitude of 10,000 feet,
- The pilot deviated from the planned route,
- The aircraft was observed flying in and out of clouds at an approximate altitude of 10,000 feet, 10 miles southeast of the accident scene and 21 miles west of the prescribed course,
- The aircraft struck the mountain peak at an altitude of 11,570 feet,
- Examination of the recovered sections of the aircraft failed to indicate any fire, structural failure, or malfunctioning of the aircraft or its components prior to impact.
Final Report: