CEN13IA107

NTSB incident investigation · Swearingen SA227-AC · Williston, ND · December 14, 2012

Incident · No injuriesIncident investigationFinal report
Date
December 14, 2012, 09:18 local (15:18 UTC)
Place
Williston, ND
Injuries
1 uninjured
Damage
No damage
Phase of flight
Takeoff
Aircraft
N3108BSwearingen SA227-AC
Defining event
Takeoff: Runway incursion veh/AC/person
Weather
Instrument (IMC) · Day
Status
Completed · report August 7, 2014
Report
Approved by Office Director
NTSB office
Central Region
Parties
FAA
Case key
85835

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

On this page

Probable cause

The snowplow driver’s failure to ensure that the runway was clear before driving onto it, which resulted in a runway incursion with a departing airplane.

Findings · 1

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.

Attention/monitoring: task monitoring/vigilancePersonnel issues › Psychological · Airport personnelSwearingen SA227-AC: 1 caseAll aircraft: 330 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 pilot reported that he made several radio calls announcing his intention to take off and that he did not hear any radio calls from other aircraft or vehicles. At the end of the ground roll, he heard a "garbled" transmission stating something about the departure runway. He stated that, as the airplane lifted off, he saw a snowplow on the runway heading in the opposite direction. He continued the takeoff and flew over the snowplow. The snowplow driver stated that he did not hear any radios transmissions from the airplane until after it was airborne and that he had been plowing for about 30 minutes and had made radio calls every 2 to 3 minutes announcing his position. Another pilot who landed about 30 minutes after the incident reported that he also saw a snowplow operating on the airport and that he did not hear any radio calls from the snowplow even after it had crossed a runway. A postincident check of the snowplow and airplane radios revealed that they were functioning properly. The reason why the pilot and snowplow driver were not aware of each other's presence could not be determined due to the lack of recorded radio transmissions and because the airplane and snowplow radios were functioning properly. However, Federal Aviation Administration guidelines to ground vehicle operators state that they need to yield right-of-way to moving aircraft and that they need to ensure that no potential conflict with a moving aircraft exists.

Factual narrative

On December 14, 2012, at 0918 central standard time, a Swearingen SA227-AC, N3108B, operated by Encore Air Cargo, was involved in a runway incursion with a snowplow at the Sloulin International Airport (ISN), Williston, North Dakota. The pilot was not injured and the airplane was not damaged. At the time of the incident, the airplane was being repositioned under 14 Code of Federal Regulations Part 91 on an instrument flight rules flight plan. Instrument meteorological conditions prevailed. The flight was originating at the time of the incident with an intended destination of the Joe Foss Airport (FSD), Sioux Falls, South Dakota. The pilot reported he made several radio calls announcing his intention to depart on runway 29. He did not hear any radio calls from other aircraft or vehicles. He initiated the takeoff and at the end of the takeoff roll he heard a "garbled" transmission stating something about runway 11/29. He stated that as he lifted off, he saw a snowplow on the runway heading in the opposite direction as him. He continued the takeoff and flew over the snowplow. The snowplow driver reported that he did not hear any radio transmissions from the airplane until after it was airborne when the pilot reported that he was airborne and leaving the area. The driver stated he had been plowing in the area for about 30 minutes and had made radio calls announcing his position every 2 -3 minutes. ISN is a non-towered airport which is fully certificated under CFR Part 139. Snow removal personnel are employees of the airport. According to the airport manager, airport vehicle drivers receive initial training upon being hired and annual training thereafter. This training addresses airport communications operations around aircraft. The airport manager also stated they were in the process of upgrading the radios in all of the airport vehicles. The snowplow involved in this incident was a new vehicle with an upgraded radio. The radio in the snowplow functioned normally when checked after this incident. Local visibility and cloud conditions recorded about 13 minutes prior to the incident was ¾ mile with mist and 100 foot overcast, respectively. Another pilot who landed about 30 minutes after the incident reported seeing a "semi truck size snow broom" sitting on taxiway A on the west side of runway 2/20. He cleared the runway and as he was taxiing to the ramp, the snowplow crossed runway 2/20 and was also on the ramp. He did not hear the snowplow driver make any radio calls. The Federal Aviation Administration FAA Guide to Ground Vehicle Operations, states: "Always yield the right-of-way to moving aircraft." The guide also states, "Before you cross a runway, ensure that no potentially conflicting aircraft are taxiing, landing or taking off."

Aircraft

Registration
N3108B
Reported as
Swearingen SA227-AC
Category
Airplane
Serial number
AC509
Airframe hours
34,538
Engines
Garrett TPE331-11U, turbo propturbo prop
Damage
No damage
Flight
Positioning · Part 91
Operator
Business Aviation Courier, doing business as Encore Air Cargo
Registered owner
Gas Wilson Inc
Airworthiness certificate
Standard, Normal
Last inspection
AAIP · November 27, 2012
Departed
ISN · Williston, ND
Destination
FSD · Sioux Falls, SD
Flight plan
IFR
Airport
ISN · Sloulin International, runway 29, 6,650 × 100 ft, asphalt

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
30
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, Without waivers/limitations
Last flight review
October 31, 2012
Seat
Left
Flight hours
5,025 total

Weather

Conditions
Instrument (IMC) · Day
Wind
170° at 5 knots
Visibility
1 statute miles
Lowest ceiling
100 ft overcast
Temperature
21 °F, dew point 21 °F
Altimeter
29.72 inHg
Observed at
ISN

Docket · 7

The files NTSB released with the investigation on July 17, 2014, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.0 MB in all.