The American company Basler Turbo Conversions recently revealed to the major defense publication Jane’s that they were offering their BT-67 Gunship as replacement for the Philippine Air Force’s (PAF) OV-10 Bronco Light Attack Aircraft.1 It was a bit of a surprise for me because prior to this announcement, all of the candidates for the Bronco’s replacement were much smaller aircraft. So let’s take a closer look at what Basler has to offer.
The BT-67 is a refurbished, modernized, and improved version of the Douglas DC-3 which first entered service with the American armed forces way back in 1936. What Basler does is to first get an old DC-3 aircraft, inspect and then do a complete overhaul on it. They then reinforce the airframe, wings and control surfaces to allow the aircraft to handle an increased maximum takeoff weight.
The forward part of the fuselage ahead of the wings is extended by one meter to increase the internal volume; The Cockpit Bulkhead is then moved forward by 1.5 m for the same reason. The shape of the Tips and the outer Leading Edge of the Wings are changed to improve their aerodynamic efficiency. Brand new and more powerful Pratt and Whitney PT6A-67R engines are then installed.
All these changes result in major improvements over the old DC-3 airframe, like having more than one-third (or 35%) more Internal Volume; 43% more Payload; one-fourth (or 24%) more Speed; and lower Stall and Landing Approach speeds which makes the aircraft easier to fly and improves its safety. The first BT-67 conversions were made in 1990, and since then around 67 conversions has been made so far that has seen service in various roles with at least seven Air Forces around the world.
For the gunship conversions, Basler is offering options such as armored Cockpits and Seats; Countermeasure Dispensers in the Fuselage and Engine Nacelles; and a Forward Looking Infra-Red (FLIR) turret. Only one country has used the BT-67 in the armed combat role, and that is Colombia where it is known as the AC-47T Fantasma and is armed with at least one three-barreled .50 cal. GAU-19 Electric Gatling Gun and one 20 mm Cannon.3
Our Philippine Air Force did operate gunship versions of the DC-3 also in the 1970s,4 as per the Stockholm International Peace Research Institute (SIPRI) we operated a total of eleven such aircraft. However, the PAF was unable to refurbish these once they reached the end of their operational lives due to one reason or another, and settled for using smaller aircraft like the MD-520MG Helicopters, the OV-10s and SF-260TP Jaguar aircraft instead for Counter Insurgency Operations (COIN).
’Air Force Requirement’
I think one way to determine how suitable the BT-67 is for our Air Force is to look at the specifications they set for the Close Air Support (CAS) bidding project,5 which is their replacement program for the OV-10 Broncos.
Of course the Air Force is expected to make some changes in its CAS requirement come the next bidding, but at this point we do not know exactly which changes they are going to make, hence the safe move for Basler would be to at least try to meet all or most of the specs that has been laid out by the Air Force as much as possible so that when the next specifications are released so they will be better prepared to meet it.
Based on the current CAS bidding specifications, below are some of the most important requirements that the BT-67 is unable to meet as of now:
- Ejection Seats and Tandem Seating – The BT-67 only has a Cabin type Cockpit with Side by Side Seating and no Ejection Seats.
Hands on Throttle and Stick (HOTAS) – The BT-67 uses a Control Wheel instead of a Throttle and Stick Cockpit Control System.
Radar Warning Receiver (RWR) – Not being offered by Basler as an option for the BT-67 as of now.
Self Sealing Fuel Tanks – Also not being offered as an option for the BT-67 as of now.
Precision Guided Munitions (PGM) Capability – The requirement calls for the aircraft to be able to use PGMs, and Basler does not offer this as an option for now.
Some of the shortcomings above I think can be corrected, like the RWRs, Self-Sealing Fuel Tanks, and even the PGM capability as other aircraft like our OV-10 Broncos and Cessna 208B have been successfully converted to have that capability after undergoing some Testing and Certifications.
With the HOTAS, they can either change the controls to Throttle and Stick, or incorporate the HOTAS features into the Control Wheel and Throttle.
But the Ejection Seats and Tandem Seating (i.e., one in front of the other) will be a lot harder if not impossible to meet. If they cannot meet them, then Basler will have to hope that the Air Force will give them a break and waive them off in the next requirements.
The Air Force will give up some aspects of Pilot Safety if it waives the Ejection Seats, but then again all Gunship versions of Transport aircraft like the AC-130 Spectre or AC-235 don’t have them also. Note that another candidate for the bidding, the AT-802U will also benefit if that requirement is waived since it doesn’t have Ejections Seats also.
’Payload and Endurance’
There are a couple of things going for the BT-67 as a CAS aircraft, though. One is that it has a large maximum Payload of 4,500 kg, which is more than three times the minimum requirement of 1,360 kg.
Another is that with a Fuel Consumption of 568 Liters per Hour at its Standard Cruising Speed and Altitude, its Endurance is at least five hours, which is twice that of the CAS’ Endurance minimum requirement of two and a half hours. And it can stay airborne even longer of up to ten hours if it operates at its most economical Loiter Speed and Altitude.
’Internal and External Weapons’
Not sure if the Pylon or External Hard points that Basler is offering right now for the BT-67 will meet the requirement that each be able to carry a minimum weight of 272 kg, but the DC-3 airframe has demonstrated before the ability to carry heavy weapons externally also on its other variants like the Lisunov Li-2NB, hence I think that Basler will likely be able to configure it as such.
The BT-67 is unique among the candidates for the OV-10 replacement as it is the only one which can be used as a Gunship with Internal Guns and can also be used as a Bomber. It has the flexibility to provide whatever weapons that is needed to be used at any given time, potentially giving it better capability as a CAS aircraft.
’Operating Cost and Patrol Operations’
Another thing going for the BT-67 is its low Operating Cost. Being a larger aircraft, I thought it would have a higher Cost Per Flight Hour (CPFH) than smaller aircraft, but Basler cites a CPFH of only around USD 1,350 for the BT-676 (assuming a Jet-A fuel price of USD 1.38 per Liter7). This figure is very competitive with the USD 1,000 CPFH cited for the OV-108 and the Super Tucano9.
It’s twin engines also provides some added margin of safety and better sense of security for the Pilots and Passengers for long flights over water like over the West Philippine Sea (WPS) for example. This is the reason why I think the OV-10 with its twin engines are more comforting for Patrol or Surveillance flights over the WPS.
I wonder though why Basler only expressed interest in our OV-10 replacement program now since the CAS bidding project has been going on for a couple of years now. Worst is the fact that relations between the US and our new President has not been very good, resulting in a US Senator recently opposing the sale of Assault Rifles to the Philippine National Police (PNP).10
It’s possible that the American Legislators will continue to oppose any new arms sales by American companies to the Philippines, and if so that will affect Basler’s plans of selling their BT-67 to us.
The BT-67 is a good aircraft, with a large Payload, long Endurance and low Operating Cost. Its twin engines also allows it to be likely better for long range, long duration Surveillance operations over water. It can also use either Internal or External weapons, depending on whichever is needed at the moment.
However, Basler does have a list of things to do if the Air Force decides to keep some of the requirements which are not present on their aircraft right now. And for those things that they cannot change, they can only hope that our Air Force will ease the requirements to allow them to compete in our CAS Acquisition Project.
And on top of that, there is also a political factor that might affect their plans, so it looks like a bit of a long shot for them at the moment. But then again, who knows. At any rate, I wish them good luck also in the coming bidding, I hope they make it.
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CAS Bidding Aircraft Technical Specifications,
Operating Cost Parameters,
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