CEN19LA092

NTSB accident investigation · Bell 407 · Union Center, SD · March 3, 2019

Accident · Minor injuriesLimited investigationFinal report
Date
March 3, 2019, 00:13 local (07:13 UTC)
Place
Union Center, SD
Injuries
1 minor, 2 uninjured
Damage
Substantial damage
Phase of flight
Standing
Aircraft
N450AMBell 407
Defining event
Standing-engine(s) shutdown: Ground collision
Weather
Visual (VMC) · Night/dark
Status
Completed · report August 10, 2020
Report
Approved by Office Director
NTSB office
Central Region
Parties
Federal Aviation Administration
FAA report
20190303000829A
Case key
99047

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The ambulance driver’s failure to see the helicopter’s rotating main rotor blades in dark night conditions, which resulted in the ambulance’s inadvertent collision with the helicopter. Contributing to the accident was the ambulance driver's failure to follow procedures when approaching the helicopter.

Findings · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Light condition: darkEnvironmental issues › Conditions/weather/phenomena · Effect on personnelBell Helicopter Textron Canada 407: 2 casesAll aircraft: 448 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The helicopter pilot, flight nurse, and flight paramedic had arrived at a landing zone to pick up a patient at night. After landing, the pilot rolled the engine throttle to idle and briefed the flight crew that they were clear to depart the helicopter. About 20 seconds later, the ground ambulance drove toward the helicopter, and the main rotor blades impacted the top of the ambulance. The flight paramedic was thrown to the ground and sustained minor injuries. The main rotor blades, tailboom, and fuselage sustained substantial damage. The ground ambulance driver stated that he saw the crew open the doors and get out of the helicopter, so he moved the ambulance ahead to get closer to the helicopter. The driver stated that he did not realize "that the helicopter blades were still rotating." The operator confirmed that the ambulance driver had received training, which indicated that ground personnel are not to approach the helicopter until the blades had stopped rotation. In addition, the general operations manual stated that ground personnel will not come beneath the rotor disk until directed to do so by the pilot.

Factual narrative

On March 3, 2019, about 0013 mountain standard time, a Bell 407 helicopter, N450AM, was substantially damaged after landing near Union Center, South Dakota. The pilot and flight nurse were not injured. The flight paramedic sustained minor injuries. The helicopter sustained substantial damage. The helicopter was owned by Air Methods and operated under the provisions of Title 14 Code of Federal Regulations Part 135. Dark night visual meteorological conditions prevailed, and a company visual flight rules flight plan was filed and activated for the flight. The on-demand air medical flight departed Spearfish, South Dakota, about 2337, and was en route to Union Center to pick up a patient.The helicopter had arrived at the landing zone at Union Center to pick up a patient. After landing, the pilot rolled the engine throttle to idle and briefed the flight crew that they were clear to depart the helicopter. About 20 seconds into the "cool down" process the ground ambulance drove towards the helicopter and subsequently the main rotor blades impacted the top of the ambulance. The flight paramedic was thrown to the ground during the collision. The main rotor blades, tail boom, and fuselage sustained substantial damage. The ground ambulance driver saw the crew open the doors and get out of the helicopter, so he moved the ambulance forward to get closer to the helicopter. The ground ambulance driver stated that he did not realize "that the helicopter blades were still rotating." Air Methods confirmed that the ambulance driver had received their training. A review of that training indicated that ground personnel are not to approach the aircraft until the blades had stopped rotation. The training also indicated that ground vehicle lights should be turned off while the helicopter is landing. An excerpt from the Air Methods General Operations Manual stated that ground personnel will not come beneath the rotor disk until directed to do so by the pilot in command; the pilot will use appropriate hand signals to do so.

Aircraft

Registration
N450AM
Reported as
Bell 407
Category
Helicopter
Serial number
54435
Built
2013
Airframe hours
2,105
Engine
Rolls Royce 250-C47B, 650 horsepower, turbo shaft
Damage
Substantial damage
Flight
Part 135
Operator
Air Methods Corp, doing business as Black Hills Life Flight
Registered owner
Air Methods Corp
Airworthiness certificate
Standard, Normal
Last inspection
Continuous airworthiness · March 1, 2019
Departed
KSPF · Spearfish, SD
Destination
Union Center, SD
Flight plan
Company VFR
Equipment
ADS-B, Satellite tracking device, Auto-pilot, Electronic multifunction display, Electronic primary flight display

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
36
Injuries
None
Certificates
Commercial, Private
Airplane ratings
Single-engine land
Instrument ratings
Helicopter
Medical
Class 2, Without waivers/limitations
Last flight review
November 27, 2018
Seat
Right
Restraint
4-point
Flight hours
2,138 total · 130 in this make and model · 2,138 as pilot in command · 18 in the last 90 days · 2 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Night/dark
Wind
330° at 13 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
-11 °F, dew point -20 °F
Altimeter
30.42 inHg
Observed at
KRAP

Docket · 4

The files NTSB released with the investigation on January 15, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.9 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.