Documentation of another air tanker encountering debris over a wildfire

air tanker hit by falling debris over Washburn Fire
Result of a BAe-146 air tanker being hit by falling debris over the Washburn Fire, July 8, 2022. SAEFCOM photo.

The day before a lead plane and a large air tanker had a close call with falling debris while on a retardant dropping sortie on the Washburn Fire in Yosemite National Park, another air tanker, a BAe-146, was actually hit while working the same fire by an object large enough to leave a dent and a large mark on top of the cockpit.

As we wrote in an earlier article, previously on July 9 a lead plane was leading Tanker 103, an MD-87, over a target when they saw a falling tree branch above the lead plane. It fell between the two aircraft, in front of the tanker. No harm done — that time.

Here is the text from a SAFECOM about an incident the previous day, July 8, 2022.

“Tanker XX was on day two of extended fire attack for the Washburn Fire. During the eighth trip to the fire we were cleared into the incident by Bravo X-X. We joined the orbit with two other DC10s. Tanker XX joined up with B X-X to drop in the area of the right shoulder with a start point on top of a ridge and then carry the load downslope. Seconds after the drop was completed both flight crew members heard an extremely loud noise that sounded like something struck the top of the aircraft. I informed B X-X of what occurred and he offered his assistance. I said we had no abnormalities but will need an inspection up return to Fresno and maybe delayed returning to the Fire.

“Upon arriving Fresno Air Attack base I informed the base that we would be delayed for an inspection of the Aircraft and was directed to the maintenance pit. Crew Chief for Tanker XX was informed of the events and obtained a lift to inspect the top portion of the Aircraft. Evidence of fire debris was observed on top of the cockpit with dent. The dent was observed and documented. The dent was within allowable limits and documented for future inspections. The maintenance crew spent extensive time inspecting the entire aircraft including the horizontal stabilizer. Fire debris was observed on top of the left horizontal stabilizer but no resulting dents were observed. After detailed visual inspections and documentation the aircraft was returned to service. Aviation Safety Comments: While Foreign Object Debris (FOD) coming from above airtankers is rare this same situation occurred the next day as well. In this subsequent event the Lead Plane prudently made note that if this condition persisted that air ops in that area would have to be halted. This is a good example of constant reassessing of risk/reward, and use of previous close-calls in making safe fireground decisions.”

This information clarifies a few words that were unintelligible in the radio conversation about the other incident on July 9 when they were referring to something that happened the day before. Here is a transcript from that conversation:

LEAD PLANE: Hey I just want to let you know that a branch went right over the top of us, pretty good size, probably 50 feet above us coming down and fell right in between Tanker 103 and myself.

AIR ATTACK: OK. Copy. So it’s repeat of yesterday’s (unintelligible) 

LEAD PLANE: That’s exactly what I’m getting at. So if we keep seeing that we might have to knock it off. I don’t want to take a chance on busting a window in an airplane or hurting an aircraft for this. 

AIR ATTACK: Absolutely. Keep me updated on this.

As I wrote in the other article, firefighting aircraft striking debris over fires is not unheard of. Here’s part of an article I wrote for Wildfire Today in 2018:

During the large vegetation fires in southern California in 2003 some of the convection columns were so powerful that the windshields on six air tankers were cracked by chunks of debris that were being hurled into the air (page D-6 in 2003 California Governor’s Blue Ribbon Report; huge 20 Mb file). One pilot saw a four by eight sheet of plywood sail past at 1,500 feet.

New livery on T-01
New livery on T-01, a BAe-146, December 18, 2020. Neptune photo.

The Washburn Fire in California’s Yosemite National Park has burned more than 3,500 acres.

Lead plane and air tanker avoid falling tree branch

Ensalados Fire Vandenberg Air Force Base
File photo of Tanker 103, July 9, 2017. Photo by Vandenberg Fire Department.

This article was first published at Fire Aviation

Yesterday July 9 a lead plane and a large air tanker had a close call while on a retardant dropping sortie on the Washburn Fire in Yosemite National Park.

There was virtually no wind over the fire most of the day and the area was smoked in causing very poor visibility making it impossible for air tankers to drop on the fire. But by 6 p.m. conditions had improved and at about 6:10 p.m. a lead plane was leading Tanker 103, an MD-87, over a target when they saw a falling tree branch above the lead plane. It 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’re not sure who the lead plane pilot was talking to, but we’ll call it “dispatcher” for now:

LEAD PLANE: Hey I just want to let you know that a branch went right over the top of us, pretty good size, probably 50 feet above us coming down and fell right in between Tanker 103 and myself.

DISPATCHER: OK. Copy. So it’s repeat of yesterday’s (unintelligible) 

LEAD PLANE: That’s exactly what I’m getting at. So if we keep seeing that we might have to knock it off. I don’t want to take a chance on busting a window in an airplane or hurting an aircraft for this. 

DISPATCHER: Absolutely. Keep me updated on this.

When a fire is burning intensely in an unstable atmosphere the convection in the rising smoke column can be powered by a tremendous amount of energy. As air at ground level rushes in to take the place of the rising column, the developing horizontal wind and the fresh oxygen feed the fire, causing an even higher level of intensity. The horizontal and then vertical movement of air can sometimes transport unexpectedly large objects up into the sky. Large columns may rotate as they rise and in extreme cases can actually become a fire tornado. You don’t want to be nearby when that happens. Fire tornados are not to be confused with small dust devils or fire whirls.

What is surprising about the incident yesterday is that the fire was smoked in most of the day, and tankers could not fly until about 6 p.m. I looked at various AlertWildfire cameras a few times and did not see any smoke columns. Maybe the cameras I saw were not able to see all of the fire, but I remember that late in the afternoon fire activity increased at the Sierra Fire Watch camera below, and columns may have developed.

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

Firefighting aircraft being damaged by debris being lofted into the air over a fire is not unheard of. Here’s part of an article I wrote for Wildfire Today in 2018:

During the large vegetation fires in southern California in 2003 some of the convection columns were so powerful that the windshields on six air tankers were cracked by chunks of debris that were being hurled into the air (page D-6 in 2003 California Governor’s Blue Ribbon Report; huge 20 Mb file). One pilot saw a four by eight sheet of plywood sail past at 1,500 feet.

As of late morning today, July 10, the Washburn Fire has burned about 1,800 acres in Yosemite National Park. About 300 of those acres are in the Mariposa Grove of giant sequoia trees, some of them 3,000 years old.

Thanks and a tip of the hat go out to Kelly.