Warren Basler – Saving the DC-3 & 34-slide PowerPoint

By Henry M. Holden

Airborne Support

The Basler BT-67 is a multi-functional airborne support aircraft. (Basler Turbo Conversions)

Warren Basler was born on a farm six miles south of the airport, and he was involved in aviation for over 50 years. Basler soloed in a Piper J-3 Cub on his 17th birthday, in 1943. He logged over 26,000 hours as a pilot, with over 10,000 hours in the DC-3 Type.

Until his tragic death in a mid-air collision, along with three other Basler employees, in March 1997, Warren Basler and his wife Patricia ran the family business. She remained active in the business until 2002.

Birth of Basler Turbo Conversions

Six years after he opened his FBO, Warren Basler bought his first DC‑3. He refurbished it, sold it, and went into partnership with his customer, arranging charter flights. Before Basler Turbo Conversions was formed in 1988, Basler Flight Service had reworked hundreds of DC-3s, modifying interiors, restoring airframes, and overhauling engines. Today, Basler Flight Service is a division of Basler Turbo Conversions LLC.

Warrne Basler

Warren Basler and his wife Patricia (Basler Turbo Conversions)

In 1983 Basler acquired the prototype of today’s BT-67 design from United States Air Craft (USAC), completing the prototype for its service introduction at Friendship Air in Alaska. The prototype, powered then by PT6A-45R turbo prop engines boosted cruise speed to 200 miles per hour but more importantly boosted reliability.

Basler recognized early a need for engine and airframe enhancements for the aging DC-3. Basler got involved with several modification concepts. Later, with two aircraft and a wish list, he began the modification and certification process.

The FAA granted Basler Turbo Conversions Parts Manufacturing Authority (PMA) for the parts it manufactures in-house. The FAA’s Manufacturing and Inspection District Office still retains manufacturing oversight.

The major modifications that Basler makes to convert a DC-3 to turbine power are done under a Supplemental Type Certificate SA4840NM issued in February 1990. Full certification was granted in December 1990. That year, Basler had ten orders for the new Basler BT-67.

Basler redesigned the DC-3’s interior, replacing old instruments, and modified the airframe. In the course of six months, a DC-3 undergoes changes in three major areas. The airframe is returned to its original specification. The radial engines are replaced with new Pratt & Whitney Canada PT6A-67R turboprop engines, certified to FAR Part 33, Amendment 10. Maintenance is less because overhaul time is at 6,000 hours verses 1,200 for the radial engines. Hartzell five-blade metal propellers are used instead of the 3-bladed props that pulled the original aircraft. Basler-converted airframes are considered to have “zero-time” with respect to accumulated fatigue damage.

The company inserts a 40-inch plug in the fuselage forward of the wing. This increases the DC-3’s volume by 35 percent, and allows the cabin bulkhead to move forward five feet. Without this plug the props of the new engine would be right outside the pilot’s window. “We did not think it was a good idea to have the ice shields in line with the cockpit,” said Tom Weigt, president of Basler Turbo Conversions, LLC. There are other performance improvements also. “A fully loaded BT-67 has a slower approach speed than a comparably loaded DC-3. At 10,000 feet, the PT6A‑67R engines pull the BT-67 along at 230 mph and burns 150 gallons per hour of jet fuel.”

The FAA required improved wing performance, longitudinal stability, and control, with the new engines. “On the old DC-3, the wing stalls as a whole, and aileron control is lost. Adding a wing cuff (a leading edge droop) increased the wing area effect. The cuff causes the outer wing to stall last, keeps airflow over the aileron which improves stall behavior,” explained Weigt.

turbo 1

Tom Weigt (Henry M. Holden)

There was an old expression was that everything on a DC-3 has been changed except its shadow. Since the BT-67 airframe has been lengthened, and the outer wing leading edge, wing tip, and tail have been modified, the BT-67 even has a new shadow.

Basler will convert an owner’s existing airframe, or provide an airframe for conversion. “We’re getting fewer requests to covert the owner’s airframe,” said Weigt. “The condition is probably more important. Airframes with relatively little corrosion and a good maintenance history are what we are more interested in. We recently obtained the Miami Valley Aviation (Ohio) fleet of six DC-3s. All but one was in airworthy condition.”

The performance of the BT-67 is well-known now, and it continues to be used for special mission applications. Now, for example, it’s the number one choice for new polar aircraft (North & South) because of its superior payload and range on skis. There isn’t a better airplane for these hostile environments at any price!

The airplane has proven to be such an excellent survey platform that it’s now the favorite for new applications and modernization in the geophysical & environmental survey world. Flights for these applications are usually made below 500’ AGL and at speeds of 100 – 125 knots where the stability performance, payload and above all the twin engine safety of the BT67 are the dominant factors in the choice of aircraft.

Basler Turbo Conversions is currently working on its 60th conversion. “What distinguishes us from other companies is we keep improving our product,” said Weigt. “Often a company goes through a strenuous development period and then it becomes a fixed product. We’ve kept ours fluid. We keep making little improvements, and small changes, and that has helped us. We are a lot more agile, and that I think is what has kept us in the game.”

fight oil spills, seed clouds and fight fires)

The Basler BT-67 can disperse chemicals to fight oil spills, seed clouds and fight fires, all the things the DC-3 did (Basler Turbo Conversions)

Basler Turbo Conversions is active in all the international markets including Europe, the Far East, the Pacific Rim, and Africa. “In the past we’ve delivered BT-67 aircraft to Colombian Police, and the Air Force,” said Weigt. “In addition to our Central and South American customers, we also serve the U.S. Forest Service, U.S. Air Force, Thailand, the Republic of South Africa, Mali, and Mauritania.

Basler Turbo Conversion, Like its forefather, the DC-3 the Basler Turbo is at home on skis and high frequency cargo flights. (Basler Turbo Conversions)

“The number one driver has been the customer asking ‘can you do this…?’ A lot of companies talk about listening to their customers, but it is a lot tougher to practice than to talk about and yet when you’re able to do it, it’s worthwhile.

The basic BT-67 aircraft costs $7 million and an all-up survey aircraft would run $13-plus million. “Every year we make some changes and most of them come from our customers who ask for example, ‘Can you build a glass cockpit? Can you take some weight out of the aircraft; can you improve the performance, or give us a military flight manual?’ they’ll ask. The good thing is we can responded to them. We are still small and nimble enough that they don’t have to go very far to get their story told. So when the request comes in we can take action.”

One area where change has made a significant difference is in the Gunship (nicknamed Fantasma). The Gunship loiters at 15,000 feet, and it is not pressurized. “In the old oxygen bottle system,” said Weigt, “we had four bottles, and if someone was shooting at you, and they hit one of the bottles, you became a flying bomb. To give the crew some protection we had to add armor protection around the bottles. Suddenly you had 600 pounds of weight added to the airplane and the oxygen was still dangerous. The new OBOGS is also at a very low in pressure, around 40 psi versus 1,800 psi in the bottles.”


Like the old Gooney Bird, this BT-67 has no problem visiting far off places such as Chad. (Basler Turbo Conversions)

Basler trimmed more weight by reengineering the floor. “We used to use the old Freuhoff style heavy duty truck floor out of truck trailers,” said Weigt. “It was a good floor but it was too heavy. We took the same concept, retooled, and now make our own floor. It is much lighter, and it reduced the weight by 350 pounds.

“We introduced a cockpit that is totally night vision compatible, because we’ve changed every light source. All of the panel lights had to be modified so they didn’t interfere with the night vision goggles. Every switch has its own and different light source. Just one switch and everything goes from day to night or from normal to night. Everything is filtered. Even at night you will see color on the weather radar.

The military wanted better single engine performance so Basler Turbo Conversions introduced a new propeller that improves performance on the airplane particularly in a single engine emergency situation. In a military situation it allows one to carry good loads out of high altitude airports. Along with that change they also introduced a flight manual just for military operations. The old C-47

The “barn doors” on the old C-47 are a convenient carry over to the BT-67 with a major improvement. Notice the upper lip which allows larger cargo such as large LD-5 container. (Basler Turbo Conversions)

The BT-67 has been certified to colder temperatures, colder than -50C for their Antarctic customers. “That combined with a new battery system exclusive to Basler is important for our customers,” said Weigt. “It is a non-hazmat battery that is virtually maintenance free. We tried the recombination technology batteries and found them to be 80 percent stronger, lighter, more durable, lower cost and they don’t require special procedures for hazardous shipping. More importantly, they suffer far less power depletion in extreme cold than we found with lead acid batteries, and the Polar applications are an important market for us. Things like that have kept the business refreshed and our customers coming along.

jack Goodale BT-67 Jack Goodale (Basler Turbo Conversions)

“A lot of the credit for where the company is has to go to Warren,” said Weigt. “What Warren did to get us to the starting point we’ve built on. Jack Goodale, our current owner, joined us in 1996 and he’s the one responsible for putting the company on solid footing and giving us the support and encouragement to grow the company. He’s helped us build an incredible infrastructure. We have an unbelievable stockpile of DC-3 parts, the barn is full, and we have 30 Sea containers out back filled with spare DC-3 parts. That’s the beauty of the DC-3. There are still a lot of parts around.”

Warren Basler once said that, “The DC-3 was a beautiful, stable, and virtually indestructible airframe going to waste. We realized that by turbinizing and modernizing the airplane it would go on for many years.” He was right. The DC-3 turbo conversion should take the old DC-3 to its 100th birthday, and beyond.

34-slide presentation on Basler Turbo Conversions PP v4

Special thanks to Tom Weigt and Peggy Johnson in the preparation of this article. For more information: www.baslerturbo.com/

For the complete story of the DC-33 see: “The Legacy of the DC-3”

©Copyright Henry M. Holden 2013


polar logistics Polar Logistics & Science (Basler Turbo Conversions)

geophysical BT-67 A geophysical BT-67 (Basler Turbo Conversion