Loss of control Accident Bell 222UT N225LL, Friday 14 April 2000
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Date:Friday 14 April 2000
Time:16:12
Type:Silhouette image of generic B222 model; specific model in this crash may look slightly different    
Bell 222UT
Owner/operator:Air Methods Corp (AMC) dba Lifelink III
Registration: N225LL
MSN: 47539
Year of manufacture:1985
Total airframe hrs:7885 hours
Engine model:Lycoming LTS101-750C-1
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:St Paul, MN -   United States of America
Phase: En route
Nature:Ambulance
Departure airport:St. Paul, MN (private)
Destination airport:St. Paul Downtown Airport, MN (KSTP)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
On April 14, 2000, at 1612 central daylight time, a Bell 222U helicopter, N225LL, piloted by a commercial pilot, was substantially damaged during an in-flight collision with a warehouse following a loss of control while in cruise flight to the St. Paul Downtown Airport/Holman Field (STP), St. Paul, Minnesota. Visual metrological conditions prevailed at the time of the accident. The positioning flight was being operated under the provisions of 14 CFR Part 91 without a flight plan. The pilot and the flight paramedic reported minor injuries. The flight departed the Abbott-Northwestern Hospital, Minneapolis, Minnesota, approximately seven minutes prior to the accident.

During cruise flight the pilot lost control of the Air Methods helicopter and an uncontrolled forced landing was made onto the top of a two-story industrial warehouse. The pylon mounted actuator support assembly had separated from the transmission case. The support assembly, attachment hardware, and portions of the transmission case were sent to the NTSB Materials Laboratory for analysis. According to the NTSB Materials Laboratory Factual Report, "... all of the studs showed progressive fatigue cracking from multiple origins." The report stated, "All but one stud fracture ... showed progression from diametrically opposed sides, typical of reversed bending fatigue loads." The report stated that all of the stud and dowel holes in the actuator support were, "... elongated on opposite sides from contact with the respective dowel or stud." The report further stated, "In addition to the elongation of the holes, the faying surfaces of the support and the transmission case were severely worn from relative movement. The directions of indicated movements and wear correspond to the axis of elongation of the respective support holes." The lead mechanic for the helicopter reported that one of the dowel pins was found during routine maintenance approximately one year prior to the accident date and the maintenance staff did not determine the identify the source of the dowel pin.

Probable Cause: The loss of clamp-up force between the transmission case and the pylon mounted actuator support assembly which resulted in fatigue failure of the threaded studs and dowel pins, the failure of the flight control system, helicopter control not being possible after the flight control failure, and the inadequate maintenance procedures by the company maintenance personnel.

Accident investigation:
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Investigating agency: NTSB
Report number: CHI00FA111
Status: Investigation completed
Duration: 1 year and 10 months
Download report: Final report

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20001212X20769&key=1

Location

Revision history:

Date/timeContributorUpdates
30-Nov-2012 03:10 TB Added
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency, ]
12-Dec-2017 18:33 ASN Update Bot Updated [Operator, Departure airport, Destination airport, Source, Narrative, ]
21-Sep-2025 09:05 Aerossurance Updated [Operator, Nature, Embed code, Narrative, ]
11-Oct-2025 23:58 Captain Adam Updated [Operator, Departure airport, Destination airport, Embed code, Narrative, Category, ]

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