Crash of a Learjet 24D in Butte: 4 killed

Date & Time: Apr 17, 1971 at 1615 LT
Type of aircraft:
Operator:
Registration:
N123CB
Flight Type:
Survivors:
No
Site:
Schedule:
Polson - Butte
MSN:
24-232
YOM:
1970
Location:
Crew on board:
2
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
4
Captain / Total flying hours:
768
Captain / Total hours on type:
147.00
Circumstances:
The descent to Butte Airport was started in poor weather conditions a zero visibility due to fog. While descending to an altitude of 6,060 feet, the airplane struck trees and crashed on the slope of a mountain located few miles from the airfield. The wreckage was found two days later and all four occupants have been killed. At the time of the accident, the airplane was flying at an insufficient altitude of 6,060 feet while the minimum safe altitude was about 8,000 feet.
Probable cause:
Improper IFR operation on part of the flying crew. The following factors were reported:
- No record of weather briefing received,
- Weather forecast unknown or not reported,
- Hit mountain at 6,060 feet approximately 1,6 NM from VOR,
- Published altitude about 8,000 feet,
- Mountains obscured by fog,
- Airport below minimums.
Final Report:

Crash of a Martin 202 in Butte: 21 killed

Date & Time: Nov 7, 1950 at 0815 LT
Type of aircraft:
Operator:
Registration:
N93040
Survivors:
No
Schedule:
Chicago – Minneapolis – Billings – Great Falls – Helena – Butte – Seattle
MSN:
9161
YOM:
1947
Flight number:
NW115
Location:
Crew on board:
4
Crew fatalities:
Pax on board:
17
Pax fatalities:
Other fatalities:
Total fatalities:
21
Captain / Total flying hours:
8291
Captain / Total hours on type:
610.00
Copilot / Total flying hours:
2873
Copilot / Total hours on type:
80
Aircraft flight hours:
6166
Circumstances:
The flight left Helena at 0753LT, using Runway 29. The flight plan, amended before takeoff, specified an altitude of 10,500 feet MSL under instrument flight rules via Amber Airway number 2 to the Whitehall (Montana) Range Station and from there to the Butte Airport via Red Airway number 2. Also, before taking off, the pilot asked the Helena Tower if the Homestake Fan normally and was informed that Butte Radio advised that it was. Following takeoff from Runway 29, the aircraft was flown in a climbing right turn so that it passed approximately over the Station as it headed south toward the Whitehall Range Station. At 0801 the flight reported to Helena that it had reached its cruising altitude. This message was acknowledged. The next message from the flight was to Butte at 0814 stating that it was over Whitehall (Range Station) at 0811 and starting descent. Butte acknowledged this message, gave that flight the station altimeter setting of 29.97, advised that the wind was south, calm, and that the Weather Bureau advised what the ceiling was lower to the east and north and better to the south and southwest. Flight 115 replied that it had vertical visibility at 10,500 feet. This was the last radio contact with the flight. A search was instituted after several futile attempts to contact the aircraft. On the following morning, the wreckage was sighted from a local search aircraft at about 0900. Ground parties immediately started for the crash site. All debris were found in a snow covered wooded area and all 21 occupants were killed.
Probable cause:
The Board determines that the probable cause of this accident was the failure of the captain to conduct the flight in accordance with the proscribed approach procedure. The following findings were reported:
- The pilot failed to follows the carrier's prescribed number 2 instrument approach procedure to the Butte Airport, which procedure is approved by the Civil Aeronautics Administration,
- The aircraft struck a mountain at about the 8,250-foot level, while on a heading of approximately 290 degrees magnetic,
- The accident occurred during a local snowstorm and under conditions of variable ceiling and visibility.
Final Report:

Crash of a Lockheed 14H Super Electra in Miles City: 4 killed

Date & Time: Jan 13, 1939 at 2115 LT
Type of aircraft:
Operator:
Registration:
NC17389
Flight Phase:
Survivors:
No
Schedule:
Chicago – Minneapolis – Fargo – Bismarck – Miles City – Butte – Spokane – Seattle
MSN:
1408
YOM:
1938
Flight number:
NW001
Crew on board:
2
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
4
Captain / Total flying hours:
11800
Captain / Total hours on type:
600.00
Copilot / Total flying hours:
4400
Copilot / Total hours on type:
600
Circumstances:
The aircraft started the take-off to the northwest at 2114LT, leaving the ground at a point approximating the intersection of the two field run rays, and crossed the field boundary in a normal climb. After reaching an estimated altitude of 500 feet, the aircraft began a slow turn to the left, thick is the usual procedure in contacting the west leg of the Miles City radio range for the purpose of continuing flight to Billings, Montana. Shortly after starting the turn, the aircraft was seen to lose altitude rapidly and descend almost to the ground before the descent was checked, and the aircraft pulled up in a sharp climb to an altitude approximating that previously attained. Immediately thereafter, the aircraft turned sharply to the loft and descended rapidly, striking the ground in a ravine and headed in a southeasterly direction with its left tang and nose slightly down. The aircraft traveled for a distance of approximately 280 feet from the point of first contact with the ground, scattering fragments along its path, and came to rest on rising terrain, where it was entirely destroyed by fire at a point 2650 feet distant from the west boundary of the Miles City airport, and 1200 feet south of a projection of north boundary of the airport. The crash resulted in the death of all person aboard the aircraft.
Crew:
C. B. Chamberlain, pilot,
R. B. Norby, copilot.
Probable cause:
Although the exact origin and source of the fire is undermined, the condition and location of the emergency-control-box cover, ‘then found, indicates the possibility of Lire at a point of leakage in the cross-feed-fuel system beta is the immediate vicinity of the cross-feed valve, and that such fire could have entered the cockpit prior to crash, through or around the box containing the emergency controls. It was concluded that the probable cause of the accident was a fire in the pilot’s control cabin, resulting in loss of control of the aircraft. Improper location and installation of that portion of the aircraft’s cress-feed fuel system which passed through the fuselage was considered as a contributory factor.
Final Report:

Crash of a Lockheed 14H Electra in Bridger Canyon: 10 killed

Date & Time: Jan 10, 1938 at 1507 LT
Type of aircraft:
Operator:
Registration:
NC17388
Flight Phase:
Survivors:
No
Site:
Schedule:
Seattle – Spokane – Butte – Billings – Chicago
MSN:
1407
YOM:
1937
Flight number:
NW002
Location:
Crew on board:
2
Crew fatalities:
Pax on board:
8
Pax fatalities:
Other fatalities:
Total fatalities:
10
Captain / Total flying hours:
10000
Circumstances:
While cruising at an altitude of 9,000 feet in good weather conditions, the twin engine aircraft went out of control, entered a dive and crashed on a wooded hill located some 22 km northeast of Bozeman. All 10 occupants were killed.
Crew:
Nick B. Mamer, pilot,
Frederick W. West, Jr., copilot.
Passengers:
T. Anderson,
I. E. Stevenson,
G. A. Anderson,
L. Levin,
Walter Ton,
A. Croonquist,
Douglas McKay,
W. E. Borgenheimer.
Probable cause:
It is the opinion of the Investigating Board that the probable cause of this accident was a structural failure of the upper vertical fins and rudders due to flutter which resulted in a loss of control of the aircraft.
Final Report: