Saturday, July 08, 2017

Piper L21B Super Cub, N99031, Bryans Machine Shop LLP: Accident occurred July 08, 2017 near Big Timber Airport (6S0), Sweet Grass County, Montana

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

NTSB Identification: WPR17LA145 
14 CFR Part 91: General Aviation
Accident occurred Saturday, July 08, 2017 in Big Timber, MT
Probable Cause Approval Date: 11/14/2017
Aircraft: PIPER L 21B, registration: N99031
Injuries: 2 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The private pilot reported that, after departure, he followed the course of a river at an altitude about level with the treetops. Although the pilot was aware of powerlines in the area, he did not see them before the airplane collided with the powerlines about 90 ft above ground level. The airplane subsequently nosed down and impacted the river, resulting in substantial damage.

According to the manager of the airport from which the airplane departed, it is not uncommon for pilots to fly at low altitudes in that area to avoid turbulent air in the summertime. He further reported that the power lines were not equipped with aerial marker balls. Following the accident, the airport manager agreed to install signage in the fixed base operator at the airport to caution pilots of the presence of power lines in that area. 

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot's decision to fly at low altitude in the vicinity of power lines, which resulted in a wire strike.

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Helena, Montana

Aviation Accident Factual Report -National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Bryans Machine Shop LLP: http://registry.faa.gov/N99031 

NTSB Identification: WPR17LA145
14 CFR Part 91: General Aviation
Accident occurred Saturday, July 08, 2017 in Big Timber, MT
Aircraft: PIPER L 21B, registration: N99031
Injuries: 2 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On July 8, 2017, about 1045 mountain daylight time, a Piper L-21B, N99031, was substantially damaged during a wire strike and subsequent impact with the Yellowstone River in Big Timber, Montana. The private pilot and his passenger were seriously injured. The airplane was owned by a private individual and operated by the pilot as a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The flight departed Big Timber Airport (6S0), Big Timber, Montana about 1030.

According to the pilot, he departed the airport to the north with a family member onboard. The pilot then turned east to follow the river and look for his sister who was participating in a water sport. The airplane was about at tree level when it collided with a set of power lines and then immediately impacted the water. The pilot reported to his father that he observed sparks and wires before the airplane entered a nose-down dive. 

The 1055 recorded weather observation at 6S0 included wind 220° true at 11 knots, visibility 10 statute miles, clear skies, temperature 25° C, dew point 11° C, and an altimeter setting of 30.20 inches of mercury. According to the U.S. Naval Observatory, the sun azimuth at the time of the accident would have been 116°.

The airplane came to rest near an eyot approximately 4 nm northeast of 6S0. Photographs from the Federal Aviation Administration revealed that the airplane sustained substantial damage to the wings, empennage, and fuselage.

The pilot reported that the airplane was on a southeast course at the time of the accident. He noted that the sun was on the horizon, but did not obstruct his vision. The pilot further remarked that he was aware of the presence of these power lines from a previous experience flying over the Yellowstone River, several years ago. 

A law enforcement representative stated that he observed a broken residential power line near the accident site and that he received reports of a disruption in power service from nearby residents around the time of the accident. The silver colored power line was one of a three phase power configuration that ran between two distribution towers on both sides of the river from a height of approximately 90 feet. The towers were about 4 nm east of the airport. 

According to the pilot's father, who is also the 6S0 airport manager, transient pilots frequently fly at low altitudes over this particular portion of the Yellowstone River to avoid turbulent air in the summertime. The airport manager further reported that the power lines were not equipped with aerial marker balls for identification. At the request of the NTSB Investigator-in-Charge, the airport manager agreed to install signage in the local fixed based operator office at 6S0 to caution pilots of the presence of power lines over the Yellowstone River.

NTSB Identification: WPR17LA145
14 CFR Part 91: General Aviation
Accident occurred Saturday, July 08, 2017 in Big Timber, MT
Aircraft: PIPER L 21B, registration: N99031
Injuries: 2 Serious.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On July 8, 2017, about 1000 mountain daylight time, a Piper PA-L21B, N99031, was substantially damaged during an impact with the Yellowstone River in Big Timber, Montana. The private pilot and his passenger were seriously injured. The airplane was owned by a private individual and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The personal flight departed Big Timber Airport (6S0), Big Timber, Montana about 0945. 

The pilot's father composed a recount of the accident flight from his son who is currently recovering from his injuries. According to his father, the pilot and a family member were flying over the river during a boating event at the time of the accident. The airplane suddenly struck a three phase power line that traversed the water and then impacted the river. At the time of the collision the pilot observed sparks and wires before the airplane entered a nose down dive. He did not observe any power lines before the airplane made contact with the power line. According to the pilot's father, who is also the 6S0 airport manager, this particular three phase power line is very thin and can be obscured by the sun depending on an airplane's direction of flight. 


A representative of the Sweet Grass County Sheriff's Office stated that he observed a broken residential power line near the accident site and that he received reports of a disruption in power service around the time of the accident.




BIG TIMBER - The Sweet Grass County Sheriff's Office received a report of an aeronautics accident at 11:05 a.m. on Saturday.

The Piper L21B Super Cub clipped a power line at the Otter Creek Fishing Access Site where the annual Yellowstone Boat Float was occurring and landed mid-stream in the Yellowstone, according to the Sweet Grass County Facebook page.

There were two occupants in the plane at the time of the crash.

A 60-year-old male and 75-year-old female were transported to Pioneer Medical Center.

The female was later life flighted to Billings.

No boaters were injured.

The plane is currently completely submerged in the river except for the tail.

The Sweet Grass County Sheriff's office is in contact with the Department of Environment Quality.

The Sweet Grass County Sheriff's Office, Sweet Grass Ambulance, Big Timber Volunteer Fire Department, and Search and Rescue all responded.

There have been some reports of loss of power in the area.

The cause of the crash is under investigation.


http://www.kbzk.com

Update to original Press Release
July 8, 2017
1735 Hours

The original 911 call came into Sweet Grass County Dispatch at 1105 hours on July 8th. Search and Rescue was able to meet up with a civilian boat that had assisted the two passengers of the plane out of the water and into their boat where the Search and Rescue boat crew was able to meet up with them and transfer care of the two patients to the Sweet Grass County Ambulance crew where they were later transported to the Pioneer Medical Center. 

A 75 year old local female resident was transported to a Billings hospital via Help Flight almost immediately and later a 53 year old local male resident was flown to a Billings hospital via Billings Clinic fixed-wing. 

The investigation is ongoing with involvement from The Sweet Grass County Sheriff’s Office, the Federal Aviation Administration and National Transportation Safety Board.

Original Release
July 8, 2017
1300 Hours

Sweet Grass County Sheriff's Office received a report of a aeronautics accident this morning. SGSO, SG Ambulance, BTVFD, and SAR all responded. The plane clipped a power line at Otter Creek Fishing access where the annual start of Yellowstone Boat Float was occurring and landed mid-stream in the Yellowstone. There were two occupants in the plane, both were rescued and are being transported to Pioneer Medical Center. No boaters were injured. Further updates will be posted when available.

BILLINGS -  The Sweet Grass County Sheriff's Office received a report of the crash of a small plane at 11:05 a.m. on Saturday.

The plane, a Piper L2B, clipped a power line near the Otter Creek Fishing Access Site where the annual Yellowstone Boat Float was occurring and landed mid-stream in the Yellowstone, according to the Sweet Grass County Facebook page.

There were two people in the plane at the time of the crash.

A 60-year-old man and 75-year-old woman were taken to Pioneer Medical Center.

Both were later airlifted to Billings for more extensive treatment; the woman is said to be in serious condition at St. Vincent's Healthcare.

No boaters were injured.

The plane is currently completely submerged in the river except for the tail.

Passing rafters were the first to respond to the scene.

Paramedics came to the site of the crash in a boat and exited with the victims at the Otter Creek Fishing Access Site.

It is unknown how the plane will be taken out of the water, but the plane will likely stay in the water overnight, according to Undersheriff Ronnenberg.

The Sweet Grass County Sheriff's Office, Sweet Grass Ambulance, Big Timber Volunteer Fire Department, and Search and Rescue all responded.

There have been some reports of loss of power in the area.

NorthWestern Energy employees were at the scene repairing the power line on Saturday afternoon.

The cause of the crash is being investigated, and the Sheriff's office will be working with the National Transportation Safety Board and Federal Aviation Administration as well.

http://www.kxlh.com

BIG TIMBER, Mont. - Authorities say a single-engine plane has clipped a power line and crashed into the Yellowstone River, but both people aboard have been rescued.

The plane crashed Saturday morning near Big Timber.

There was no immediate word on whether the plane's occupants were injured.

The Sweet Grass County Sheriff's Department says the cut power line left some Big Timber residents without electricity. 

Sheriff's deputies say utility crews were working to restore service.

Officials say boaters participating in the annual Yellowstone Boat Float were in the river but none were injured.

More than 100 people were in the river nearby at the time.

Sheriff's spokeswoman Brooke Osen says a civilian boat picked up the plane's occupants.

The cause of the crash was under investigation.

http://www.nbcmontana.com

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