Lead plane and tanker plane avoid falling tree branch

File photo of Tanker 103, July 9, 2017. Photo by Vandenberg Fire Department.

This article first appeared on Fire Aviation

Yesterday, July 9, a lead plane and a large tanker plane had a close call during a retarder drop sortie over the Washburn Fire in Yosemite National Park.

There was virtually no wind over the fire most of the day and the area was smoky, causing very poor visibility, preventing air tankers from falling on the fire. But by 6 p.m. conditions had improved and at about 6.10 p.m. a lead aircraft was directing Tanker 103, an MD-87, over a target when they saw a tree branch fall. above the lead aircraft. He fell between the two aircraft, in front of the tanker.

Twitter user Robert, @Rob_on_sisukas, captured an audio recording of the radio conversation. We don’t know who the pilot of the lead plane was talking to, but we’ll call him “dispatcher” for now:

LEAD PLANE: Hey, I just want to let you know that a branch went right over us, pretty good size, probably 50 feet above us and fell right between Tanker 103 and me- same.

DISTRIBUTOR: Okay. Copy. So this is yesterday’s rehearsal (unintelligible)

LEAD PLANE: That’s exactly what I’m getting at. So if we keep seeing this, we may need to remove it. I don’t want to take the risk of breaking a window on a plane or hurting a plane for that.

DISTRIBUTOR: Absolutely. Keep me posted on this.

When a fire burns intensely in an unstable atmosphere, the convection in the rising column of smoke can be fueled by an enormous amount of energy. As the air at ground level rushes to take the place of the riser, the developing horizontal wind and fresh oxygen fuel the fire, causing an even higher level of intensity. The horizontal and then vertical movement of air can sometimes carry surprisingly large objects across the sky. Large columns can spin as they rise, and in extreme cases can actually become a fire tornado. You don’t want to be around when this happens. Fire tornadoes should not be confused with small dust devils or fire whirlwinds.

What is surprising about yesterday’s incident is that the fire smoldered for most of the day and the tankers were unable to fly until around 6pm. I looked at several AlertWildfire cameras a few times and saw no smoke columns. Maybe the cameras I saw weren’t able to see all of the fire, but I remember late afternoon fire activity increased at the Sierra Fire Watch camera below, and columns may have developed.

Washburn Fire at 5:24 p.m. on July 9, 2022
Washburn Fire at 5:24 p.m. July 9, 2022. Sierra Fire Watch image.

Firefighting aircraft damaged by debris thrown through the air over a fire are not uncommon. Here is part of an article I wrote for Wildfire Today in 2018:

During the large wildfires in Southern California in 2003, some of the columns of convection were so strong that the windshields of six air tankers were cracked by pieces of flying debris (page D-6 of the 2003 California Governor’s Blue Ribbon Report; large 20MB file). A pilot saw a sheet of four-by-eight plywood pass at 1,500 feet.

Late morning today, July 10, the Washburn Fire burned approximately 1,800 acres in Yosemite National Park. About 300 of those acres are in the Mariposa Grove of giant sequoias, some of which are 3,000 years old.

Thank you and a tip of the hat to Kelly.

Author: Bill Gabbert

After working full time in wildfires for 33 years, he continues to learn and strives to be a student of fire. View all posts by Bill Gabbert

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