ASN Wikibase Occurrence # 246041
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| Date: | Saturday 19 April 1952 |
| Time: | 17:30 |
| Type: |  Bell 47D |
| Owner/operator: | Syndicat de la Cellulose Africaine |
| Registration: | OO-CSC |
| MSN: | 19 |
| Year of manufacture: | 1948 |
| Fatalities: | Fatalities: 1 / Occupants: 1 |
| Aircraft damage: | Substantial |
| Location: | Kabelwe -
 Congo (Democratic Republic)
|
| Phase: | En route |
| Nature: | Agricultural |
| Departure airport: | |
| Confidence Rating: |  Information verified through data from accident investigation authorities |
Aircraft was tasked with spraying insecticides in a certain zone over the Lualaba river. While spraying the river surface from an altitude of around 5 meters, the aircraft passed two river boats moored to the river banks (CITO and COUSIN). While the aircraft cleared CITO at a relatively safe distance, its blades hit the upper structure of COUSIN) causing damage to the boat. Debris of the superstructure was projected into the cockpit, striking the pilot and killing him instantly. The aircraft subsequently crashed and sank; it and the body of the pilot were recovered the next day.
GENERAL FINDINGS RELATING TO THE ACCIDENT -
• Eyewitness testimonies relating to the operation of the engine and changes in the aircraft prior to the accident rule out any possible engine failure or flight control malfunction. This last point was confirmed by the normal operation of the aircraft controls after recovery of the wreckage.
• Examination of the airframe and the engine as well as the observations listed above eliminate any maintenance error as a possible cause of the accident.
• The insecticide tanks being correctly fixed in the places provided by the manufacturer and the spraying operations having been carried out for 20 minutes prior to the accident rule out center of gravity issues or overloading damage to the aircraft as possible factors in the accident.
• As the aircraft was working correctly, the accident should be attributed to the following cause: when passing port side of the boat "COUSIN" the pilot did not maintain sufficient distance between his helicopter and the flank of the boat. –
Given the straight trajectory followed by the aircraft, and the excellent visibility that prevailed at the time, the pilot
voluntarily chose this dangerous distance. -
Indeed, while at the height of the barges he was at a reasonable lateral distance from them, he continued the trajectory so as to reduce the lateral distance to just 75 cm while adjoint to "COUSIN", without changing his distance relative to the ship while covering its length (30 meters, being the length of the cabin roof).-
Once he arrived adjoining the ship's bridge, four possible causes could have provoked the collision:
1. a gust of wind may have occurred at this time and caused the aircraft to veer towards the boat,-
This would explain the maneuver of the pilot who set the collective all the way up and power at maximum to regain height.-
It should be noted that the wind was blowing at this time towards the boat and in an approximately perpendicular direction to the longitudinal axis of the latter.-
2. It is possible that the bearing and flux flow of rotor air have been influenced by a sudden upset from a lateral obstacle (in question the side of the boat) and thus cause the fatal deviation of the aircraft. The proximity of this obstacle (75 cm) cannot only aggravate the phenomena of turbulence and irregularities of support which result therefrom.
3. At the time of the accident, the wind coming from the right bank had an estimated speed of 10 km/hour and a direction perpendicular to the axis of the boat.-
The helicopter could therefore have deviated without the pilot noticing (drift effect) -
4. The pilot may have been dazzled by the sun whose rays came to him from the right front side and formed an angle
of 60° with its trajectory.-
This glare could cause the pilot to misjudge the distance separating him from the boat.-
In any event, the accident was due to the carelessness of the pilot who neglected to keep a sufficient distance between his device and the boat "COUSIN"
Sources:
AAIU Belgium
https://www.helispot.be/hs/documents/ongevallen/oo-csc.pdf
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 15-Jul-2023 16:00 | Anon | Updated |
Corrections or additions? ... Edit this accident description
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