DC-3 air tanker used for dust control in Thailand

The turbine-powered aircraft was operated by the Thai Air Force

BT-67 DC-3 Thailand
A BT-67, modified from a DC-3, is used to improve the air quality in Thailand. Thai PBS photo.

Thai PBS tweeted this photo of a DC-3 dropping water in an effort to improve the air quality in Thailand on January 15, 2019.

The air tanker made several drops of 790 gallons each near Don Mueang Air Force Base and in the Chatuchak area.

Thai PBS described the mission. This excerpt has been very crudely translated by Google Translate:

The Air Force brought the BT-67 aircraft from the 46th Airborne Division, Phitsanulok Province to carry 3,000 liters of water in the tank under the machine. Flying water droplets at a height of about 1,500 feet around the Don Mueang Air Force Base as the first area In order to alleviate PM 2.5 dust problems that are beyond the standard value until they start affecting health.

Type 2 transport aircraft, or BT-67 aircraft belonging to the 46th Air Force Division, Phitsanulok, are aircraft that the Air Force uses to support the missions of the Royal Rain Flying to control wildfire. And water spraying, water spray, alleviating haze / dust problems. In which the flight of the water lapses, each flight will carry water to scatter about 3,000 liters per trip. Scattering water from the height above the target area Which will cause water droplets to spread over a wide area And capture with dust to alleviate the severity of the problem.

It is not clear from the roughly translated article if the water drops are expected to physically remove particulates as the water drifts downward, or if it will wet the ground to reduce the amount of dust that becomes airborne.

The aircraft has had its radial engines replaced with turbine engines. The conversion by Basler results in the aircraft’s model name changing from DC-3 to BT-67.

According to Wikipedia:

The conversion includes fitting the airframe with new Pratt & Whitney Canada PT6A-67R turboprop engines, lengthening the fuselage, strengthening the airframe, upgrading the avionics, and making modifications to the wings’ leading edges and wing tips.

Due to the slightly higher fuel consumption of the turbine engines of the BT-67, compared to the original piston designs fitted to the standard DC-3, range on the standard fuel tank, with 45 minute reserve, is reduced from 1,160 to 950 nautical miles (2,150 to 1,760 km). Basler provides a long-range fuel tank which increases the aircraft range to 2,140 nmi (3,960 km).

Thanks and a tip of the hat go out to Isaac.
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USFS DC-3 listed on auction site

The auction closes July 22 at 11 a.m. CDT

DC-3 USFS
DC-3 in a hangar at McClellan March 23, 2016. Photo by Bill Gabbert.

The last DC-3 formerly owned by the U.S. Forest Service is listed for sale on the General Services Administration auction website. Built in 1944, it retired from smokejumper duty in December of 2015.

Here is the description of the aircraft at the GSA website:

Douglas DC-3T, 1944 S/N 33567, N115U. 18800.9 hours aircraft TT. P&W PT6A-67R engines, Left 2367.7 SMOH, Right 5831. SMOH HC-B5MA-3 propellers 543.0 SPOH This is an “As is where is” sale. Attached Equipment List Further details on invitation for bid DOUGLAS DC-3T 1232TD612400011

The last bid was $1,000, but the reserve has not been met. It is currently at McClellan Air Field in California.

The 72-year old aircraft, first operated by the Royal Air Force, was manufactured as World War II was winding down. The radial piston engines were replaced 25 years ago with turbines by Basler, extending its life while providing more reliability and less maintenance. The aircraft’s sister, Jump-42, another DC-3, retired in November, 2012.

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

The last Forest Service DC-3 retires

The last DC-3 operated by the U.S. Forest Service retired this week following a ceremony at the Missoula smokejumper base.

N115Z smokejumper DC-3
The last U.S. Forest Service DC-3 departs from Missoula December 10, 2015 after retiring from smokejumper duty. Image by Jason Junes.

Known to the jumpers it hauled as Jump 15, it took off December 10 from Missoula and a flew to McClellan Airfield in Sacramento at 16,000 feet and 200 mph, unpressurized of course. There it will await an auction and a new owner.

The 71-year old aircraft, first operated by the Royal Air Force, was manufactured as World War II was winding down. The radial piston engines were replaced 24 years ago with turbines by Basler extending its life while providing more reliability and less maintenance. The aircraft’s sister, Jump-42, another DC-3, retired in November, 2012.

Approximately 607 DC-3s were built between 1936 and 1942. At that time their cost was $79,000. Most of them had 14-cylinder Pratt and Whitney radial engines.

With the two DC-3s now gone, the smokejumpers will be using some of the 15 C-23B Sherpa aircraft they received from the Army and two De Havilland DHC-6 Twin Otters. The Forest Service has been contracting for two additional Twin Otters but those will be phased out as the C-23Bs transition into the fleet after going through modifications, maintenance, and painting.

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

When will the last USFS DC-3 TP retire?

USFS DC-3 retires
J-42, a U.S. Forest Service DC-3 TP at its retirement ceremony at Ogden, Utah, October 24, 2012. USFS photo.

Since one of the two U.S. Forest Service DC-3 TPs retired in 2012 and was sold in 2013, there has been speculation about how many years the last USFS DC-3 TP would continue to haul smokejumpers.

It has been 23 years since the two aircraft had their radial piston engines replaced with turbines in 1991 by Basler.

The remaining DC-3 TP is 71 years old. USFS spokesperson Jennifer Jones said, “Economic, operational and risk analyses have shown that the DC-3 TP has fulfilled its useful life as a smokejumper platform.”

When we asked if the rumors are true that the last DC-3 TP will retire in 2015, Mrs. Jones said it will be replaced by one of the 15 C-23Bs that the USFS recently acquired from the Army, “but no precise date has been set for that yet.”

The C-23B, due to begin transitioning into the USFS fleet in 2016, has issues with high density altitude, and some pilots have questioned how useful it will be at high altitude smokejumper bases such as West Yellowstone and Silver City. We asked Mrs. Jones about this, and she said the USFS owns two De Havilland DHC-6 Twin Otters and contracts for two others. After the transition to the C-23B the agency will retain the two Twin Otters they own, “to ensure the capability to perform short field/backcountry airstrip and high density altitude missions.”