1950 — Nov 7, Northwest Orient #115 deviates from course, hits mt. ridge ~Butte, MT–all 21
–22 NFPA. “Large Loss Fires of 1950; Transportation; Aircraft.” The Quarterly, 44/3, Jan 1951, p.249.*
–21 AirDisaster.com. Accident Database. Accident Synopsis 11071950.
–21 Aviation Safety Network. Accident Description. Northwest Orient Airlines, 07 Nov 1950.
–21 CAB. AIR. Northwest Airlines, Inc., Martin 202, Near Butte, Montana, Nov 7, 1950.
*The National Fire Protection Association death toll of 22 is incorrect, as other cited sources prove.
Narrative Information
Civil Aeronautics Board Accident Investigation Report (File No. 1-0125):
“The Accident
“Northwest Airlines Flight 115 of November 6, 1950, a Martin 202, N 93040, crashed about 2½ miles east of the Butte, Montana airport at about 0815 MST, November 7, 1950. The aircraft was demolished, and all 17 passengers and four crew members were killed…
“History of the Flight
“Flight 115 originated at Chicago, Illinois for Seattle, Washington, via intermediate stops….” [One of those was Helena, MT where it took off at 0753 for another stop in Butte, MT.] The outgoing crew from Billings consisted of Captain Lloyd Lampman, First Officer James Huff and Stewardesses Nohr and White….
“At Helena, the aircraft was fueled…The flight plan, amended before takeoff, specified an altitude of 10,500 feet MSL under instrument flight rules….
“….At 0801 the flight reported to Helena that it had reached its cruising altitude….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 the flight the station altimeter setting of 39.97, advised that the wind was south, calm, and that the Weather Bureau advised that 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.
“Investigation
“It was determined that at approximately 0815 the aircraft had struck the eastern slope of a ridge about 30 feet below its crest, at an altitude of about 8,250 feet…The site of impact was approximately 2½ miles east of the control tower at the Butte Airport, and about 1½ miles to the right of the center of the on-course signal…to Butte….Distribution and spread of the wreckage indicate that the aircraft struck while about level longitudinally….
“The extremely rough terrain was snow-covered and some scattered parts of the wreckage were burned in varying degree; there was no indication of fire prior to impact. There does not appear to have been any failure of the control system or of the aircraft’s structure prior to impact….
“Analysis
“As the flight crashed on the lee side of a ridge only about 30 feet below its crest, there arises the question of possible turbulence and downdrafts at the scene of the accident. Upper air wind observations on the west side of the ridge indicated that the wind was 15 knots or less at the lower altitudes from a direction ranging from nearly paralleling to quartering the ridge. Above 7,000 feet MSL the wind had an increasing westerly component and in the free air at 8,000 feet it was indicated to have been about 250 degrees at 18 knots. This condition would not indicate a build-up to a very high velocity over the crest of the ridge….
“….the Boards evaluation of all the evidence obtained shows that both the Whitehall Range and the Homestake Fan Marker were functioning normally. It is, therefore, concluded that had Flight 115 utilized these facilities, as prescribed by the carrier and approved by the Civil Aeronautics Administration, the accident would not have occurred….
“There was testimony concerning the practice of NWA pilots turning on to the west leg of the Whitehall Range, from the north leg of the range, while short of the range station, and that some NWA pilots apparently believed that the visual and aural signals from fan markers occur over the same area. It was also testified that ‘on and off’ instrument technique is sometimes practiced under certain weather conditions during the approach to Butte from the east….
“Mention has been made of another ridge more or less paralleling the ridge that was struck and about three or four miles to its east. They are somewhat similar and it is possible that captain Lampman, flying ‘on and off’ instruments may have mistaken the easterly ridge for the ridge which was struck during the letdown to Butte….
“…the Board concludes that the final few miles prior to the crash were flown visually under conditions of intermittent and alternating instrument and visual flight and appreciably to the right (north) side of both the west leg of the Whitehall Range leg and the Homestake Fan Marker, and that the aircraft struck the ridge during a local snowstorm.
“The record in this case clearly shows that the captain demonstrated a complete lack, of flight discipline by deviating from the prescribed instrument approach procedure to Butte. It is obvious that had he followed such proscribed procedures, the accident world not have occurred. However, the company is responsible for the establishment and execution of a comprehensive, pilot training program as required by the Civil Air Regulations and designed to require the highest degree of efficiency in scheduled carrier operations. Certainly this program was not as effective as required.
“As a result of this and subsequent accidents involving Northwest Airlines, the Civil Aeronautics Administration took the following actions:
1. Required higher ceiling and visibility minimums for Northwest Airlines’ operations on both domestic and international routes. (Effective January 26, 1951),
2. Required the establishment of a concentrated pilot training program for all pilots…;
3. Required a comprehensive inspection of all company aircraft. (Effective Feb 1, 1951);
4. Restricted operations to 225 miles for 4-engine aircraft, and 150 for 2-engine aircraft unless an airport having the higher weather minimums was available within such distances. (Effective January 26, 1951);
5. Restricted flight schedules to allow sufficient time to accomplish necessary maintenance. (Effective February 1, 1951.
….
“Findings
“On the basis of all available information the Board finds that:
“….
“4. The pilot failed to follow the carrier’s prescribed No. 2 instrument approach procedure to the Butte Airport, which procedure is approved by the Civil Aeronautics Administration.
….
“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 prescribed approach procedure.” (Civil Aeronautics Board. Northwest Airlines, Inc. – Martin 202, Near Butte, Montana, Nov 7, 1950.)
Sources
AirDisaster.com. Accident Database. Accident Synopsis 11071950. Accessed at: http://www.airdisaster.com/cgi-bin/view_details.cgi?date=11071950®=N93040&airline
Aviation Safety Network. Accident Description. Northwest Orient Airlines Flight 115, 07 Nov 1950. Accessed 2-17-2009 at: http://aviation-safety.net/database/record.php?id=19501107-0
Civil Aeronautics Board. Accident Investigation Report. Northwest Airlines, Inc., Martin 202, Near Butte, Montana, Nov 7, 1950. Washington, DC: CAB, June 22, 1951, 24 pages. Accessed 8-20-2023 at: file:///C:/Users/Wayne/Downloads/dot_33404_DS1-2.pdf