ASN Wikibase Occurrence # 233595
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| Date: | Wednesday 4 March 2020 |
| Time: | 19:42 LT |
| Type: |  Bell 206L-1 LongRanger II |
| Owner/operator: | Air Evac Ems Inc |
| Registration: | N32AE |
| MSN: | 45327 |
| Year of manufacture: | 1979 |
| Total airframe hrs: | 27820 hours |
| Engine model: | Rolls Royce 250-C30P |
| Fatalities: | Fatalities: 0 / Occupants: 4 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | NW of Clark, Randolph County, MO -
 United States of America
|
| Phase: | Landing |
| Nature: | Ambulance |
| Departure airport: | Kirksville, MO (MU92) |
| Columbia, MO (91MO) | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The pilot of the helicopter air ambulance flight reported that, while en route on the night patient transfer flight, he received low rotor rpm warnings and engine power dropped below 90%. He reduced collective and turned toward a field to perform a precautionary landing, during which the helicopter touched down hard, resulting in substantial damage to the tail boom.
A postaccident examination of the helicopter revealed that a pneumatic line, which had been leak-checked about 115 hours before the accident flight, had separated near its filter connection. A leak in the pneumatic line can cause the engine control system to enter a sub-idle fuel flow condition, resulting in a loss of engine power.
An examination of the pneumatic line and filter revealed that the tube had fractured completely through at the toe of the weld between the tube and its filter fitting. Surface smearing was present on sections of the separation; however, the separation exhibited surfaces consistent with fatigue that initiated near the top of the tube. The tube's outer diameter surface near the elbow separation exhibited rub damage. A red ribbed hose was present in the engine bay near the tube separation and the ribbed hose exhibited discoloration on its outer surface consistent with rubbing against the pneumatic tube. One weld exceeded its component specification; the remaining tube and weld measurements met their component specifications. The tube, fitting, and weld materials met specifications.
According to the engine manufacturer, the accident was the first occurrence of a separation involving this revision of the pneumatic line over 17 million fleetwide flight hours.
The cause of the fatigue could not be attributed to the hose and pneumatic tube rubbing or any other issue, and the reason for the failure could not be determined based on the available information.
Probable Cause: The fatigue failure of the pneumatic line for reasons that could not be determined, which resulted in a loss of engine power and subsequent hard landing.
Accident investigation:
 |
|
Sources:
NTSB CEN20LA113
FAA register: https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=32AE
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 05-Mar-2020 04:11 | Geno | Added |
| 05-Mar-2020 06:38 | RobertMB | Updated [Aircraft type, Registration, Cn, Operator, Location, Source, Damage, Narrative] |
| 28-Mar-2020 01:53 | Captain Adam | Updated [Damage, Narrative] |
| 14-Jan-2021 07:56 | Aerossurance | Updated [Source] |
| 08-Feb-2021 18:37 | harro | Updated [Source, Category] |
| 27-Feb-2021 18:31 | harro | Updated [[Source, Category]] |
| 08-May-2021 16:51 | harro | Updated [[[Source, Category]]] |
| 08-Jul-2022 09:27 | ASN Update Bot | Updated [Time, Operator, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative, Category, Accident report] |
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