The AT-802U Air Tractor versus the A-29B Super Tucano

An AT-802U Air Tractor. Photo courtesy of Aerofossile2012 thru Flickr
An AT-802U Air Tractor. Photo courtesy of Aerofossile2012 thru Flickr

Aside from the AT-6B Texan II, another aircraft worth considering in the turboprop Light Attack Aircraft market is the AT-802U. This aircraft is interesting because it made claims about long endurance, high payload and excellent ballistic protection to make it a good candidate for the Philippine Air Force’s (PAF) planned Close Air Support (CAS) acquisition. Hence in this blog, I will be comparing it to the established leader of the turboprop attack aircraft market, the A-29B.

‘Aircraft Backgrounds’
The EMB314 or A-29 is made by Brazil’s “Embraer” company, it is a turboprop aircraft designed for light attack, Counter Insurgency (COIN), CAS and Aerial Reconnaissance missions in low threat environments, and also for Pilot Training. It is based on the EMB312 Tucano Trainer aircraft, but has a longer fuselage, more powerful engine and strengthened airframe. It first flew in 1999, and since then over 170 aircraft has been built and went into service in 11 countries around the world. The A-29B is the two-seat version of the aircraft, and its official nickname is the “Super Tucano“.1

The AT-802U is made by the American company “Air Tractor Incorporated“, and it is also a turboprop aircraft designed for the light attack role. It is based on the commercially successful AT-802 of which over 500 aircraft have been built and served in civilian markets all over the world since its first flight in 1990. The AT-802 is claimed by Air Tractor as the current largest agricultural aircraft in the world and is used mainly for crop dusting or fire-fighting purposes.

The AT-802U is the special armed version of the AT-802 with engine and cockpit armor, a bulletproof windscreen, self-sealing fuel tanks, and structural reinforcements which first flew in 2009, and its official nickname is the “Air Tractor”. Its first and only customer so far has been the United Arab Emirates who bought 10 aircraft which were all delivered in 2011.2 3

‘Iomax Archangel’
Things get a bit confusing from hereon for the AT-802U because the US company responsible for weapons and systems integration for the Air Tractor, Iomax, has also launched a COMPETING aircraft design based on the Thrush 710 made by another American company, “Thrush Aircraft“. Reports say that Iomax chose the Thrush 710 because it allowed them to make changes in the production line as necessary, something they reportedly are unable to do with the AT-802. Both the Thrush 710 and AT-802 are based on the same aircraft design made by Leland Snow, hence they look almost exactly the same but with small differences.4

Iomax named their armed version of the Thrush 710 as the “Archangel“, and I initially thought of using it for this comparison, but the problem is that I found Iomax to be less than complete in terms of providing information about their aircraft, unlike Air Tractor wherein they provided complete details about the AT-802U (which they still market in their website). If you go to Iomax’s website for the Archangel,5 for example, you won’t find important details like Empty Weight, Wing Area, Maximum Speed, etc. I tried to ask these from them, but they never answered back.

Perhaps Iomax is just more “savvy” (deceptive?) as some of these information do reveal the WEAKNESSES of their aircraft, as we shall see later on. At any rate, the performances of the Archangel and AT-802U should be very similar, and in fact the AT-802U might even be slightly better because it has a heavier take off weight and a lot more pylons (eleven as opposed to only seven) than the Archangel.

‘Evaluation Notes’
For the “Maneuverability” and “Payload and Range” sections, the following considerations were made:
– Weights with 100% internal fuel was used to try to simulate the aircraft going into combat with full internal fuel after dropping their External Fuel Tanks.
– The weights of the armaments were not included as the RATIOS and DIFFERENCES BETWEEN BOTH AIRCRAFT will remain the same if they will be armed with the same type and same number of armaments.
– Data for each aircraft was derived from various websites at 6 7.

‘Manueverability’
For both aircraft’s maneuvering capability, I am looking at their WING LOADING* and POWER TO WEIGHT RATIO.* I would’ve wanted to take a look at more aspects like Stall Speed, Maximum Alpha, etc., but those data are hard to come by for both aircraft. Hence, these should suffice for now. Remember that a lower Wing Loading means the aircraft can turn tighter and vice-versa, and a higher Thrust-to-Weight Ratio means the aircraft can go faster going straight up or straight down and vice-versa. I did not include the criteria of LIMIT LOAD FACTOR as I could not find any references in the internet about the AT-802U’s G-limit. For some reason, the manufacturer did not publish it.
AT-802U-Super_Tucano_Maneuverability

SUMMARY
– WING LOADING: A good 22% advantage for the AT-802U over the A-29B
– POWER TO WEIGHT RATIO: A huge 57% advantage for the A-29B over the AT-802U

+++ Despite the fact that the AT-802U is almost 60% heavier with a full internal fuel than the A-29B, it has a lower wing loading by virtue of its large wing which is an impressive 92% larger than the A-29B, hence “soaking” off much of that weight over a larger area. A caveat, though: Air Tractor did NOT publish the G-limit of the AT-802U, and if it turns out that it has a lower G-limit than the A-29B, then that advantage of lower wing loading maybe cancelled off altogether depending on how large the difference is.

+++ Unfortunately for the AT-802U it only has the same engine power as the A-29B, and all that added weight results in a much lower Power to Weight ratio and thus lower performance in terms of climb rate or dive speed.

+++ I did not bother to compare the maximum speeds of both the AT-6B and the A-29B because they were very similar, only a couple of kph apart. However, in this case I had to publish it because there is a LARGE difference in speed between the two aircraft at 50% or almost 200 kph difference. The reason for the AT-802U’s lack of speed is mainly because of its LARGE WING: It soaks up the weight of the aircraft for a lower wing loading, but it also creates a lot of DRAG. Couple this with its large size and heavier weight, it results in a lower maximum speed for the aircraft using the same engine power. Speed is critical because:
– A faster aircraft will reach the combat area SOONER
– If an aircraft is too slow, it will be easier to hit and thus more vulnerable to anti-aircraft fire
– Higher speed means more Kinetic Energy during launching of weapons enabling some missiles and bombs to have longer range

‘Payload and Range’
For Range, I am using INTERNAL FUEL FRACTION (INTFF)* as a rough indicator how far each aircraft can go based on the internal fuel available to them.
AT-802U-Super_Tucano_Payload

SUMMARY
– INTFF: A very impressive figure of over 200% for the AT-802U, indicating that it can travel a full 2 times further than the A-29B.
– PAYLOAD: Favors the Super Tucano at full internal fuel as it can carry 30% (355 kg) more load than the AT-802U.

A Sidewinder-armed Super Tucano. Photo courtesy of A-29 Super Tucano thru Flickr
A Sidewinder-armed Super Tucano. Photo courtesy of A-29 Super Tucano thru Flickr

+++ Excellent fuel load for a prop-driven aircraft with the AT-802U at over two thousand kilograms, lending credibility to Air Tractor’s claims of a 10-hour endurance. The reason for this large fuel load is because of its background as a Crop Duster or Fire Fighting aircraft wherein it has large liquid containers between the engine firewall and the cockpit and also under the belly which has been converted to carry fuel instead on the AT-802U. And even with a full internal fuel load, the AT-802U can still carry well over a thousand kilogram of external payload.

+++ The AT-802U carries so much fuel that it could actually trade off some of that fuel along with endurance and range so it can carry more external payload as needed. For example, if the AT-802U matches the fuel factor of the A-29B which is at 0.10, it will be able to carry 2,714 kg of payload, or 43% more than the A-29B.

‘Avionics and Weapons’
Although these aircraft are propeller-driven and thus may seem “obsolete” to some, they actually have some of the most advanced Avionics available in the world today, ranging from Heads Up Displays (HUDs), Hand On Throttle And Stick (HOTAS) controls, “Glass” cockpits, etc. Here is a list of the Avionics Suite and weapons of both aircraft:
AT-802U-Super_Tucano_Avionics

SUMMARY
– WEAPONS: The advantage goes to the Super Tucano’s two internal guns despite the fact the AT-802U has six more additional hardpoints.
– AVIONICS: The A-29B has the advantage of having a Missile/Radar Warning Receiver (M/RWR) and Counter Measure Dispenser System (CMDS) built in.

+++ Although the AT-802U has a LOT more hardpoints than the Super Tucano, the A-29B’s internal guns have less drag than the comparable gun pods that the AT-802U will have to carry.

+++ The Iomax Archangel is confirmed to have M/RWR and CMDS, but AT-802U offers it only as an “option”.8 At any rate, the addition of these two systems will result in a heavier empty weight which will mean less fuel and external payload for the aircraft.

‘Cockpit Visibility’
Unlike with the AT-6B, Embraer did not put up a webpage dedicated to showing the superior features of the A-29B over the AT-802U, perhaps because they don’t consider the AT-802U as a major competitor. At any rate, one clear advantage that the A-29B has over the AT-802U is cockpit visibility. The A-29B uses a clear bubble canopy, while the At-802U uses a canopy lined heavily with steel frames and thus severely limiting visibility.

Another issue is that the cockpit is set way back in the body so that long, big nose housing the engine and fuel limits the visibility of the ground in front of the pilot. Even worst is that it uses the conventional, tail-dragger type of landing gear which keeps the nose of the aircraft high when it is taxiing on the ground, reducing frontal visibility even further and makes it a little bit more difficult for the pilot to see where he is going, which could be a challenge especially for novice pilots.

‘Other Considerations’
While the AT-802U’s steel-lined cockpit reduces visibility, it also allows the cockpit to use ballistic glass for added protection against enemy fire, hence the AT-802U traded off visibility for armor protection. However, this is somewhat offset by the fact that it doesn’t have ejection seats, so the pilots will have to manually crawl out of the plane to bail out, or rely on the air bags, secure seat belts and a sturdy landing gear when ditching (i.e. crash landing) the aircraft.

Another issue is the fact that the AT-802U has an airconditioned but NOT a pressurized cockpit, limiting its operating altitude to around 3,800 m. The Super Tucano with its pressurized cockpit can operate all the way up to its service ceiling of 10,600 m. Only a minor issue as these aircraft are expected to operate close to the ground anyway, MOST of the time, but not ALL of the time. In SOME situations, for example, like when it would be SAFER against ground fire to drop PGMs from beyond 3,800 m altitude, that option is not available with the Air Tractor.

‘Parting Shot’
Summarizing the advantages for the AT-802U Air Tractor:
– Can travel twice as far or carry more payload
– Has a lot more endurance or time on station
– Has a lot more hardpoints
– Has better ballistic protection
– Better rough field performance
– Potentially more maneuverable
– Reportedly has much less Operating Cost
– Reportedly has lower price

Summarizing the advantages for the A-29B Super Tucano:
– Can carry more payload if both aircraft are at full internal fuel
– Is much faster making it less vulnerable to ground fire
– Can reach combat areas faster
– Imparts more Kinetic Energy during launch allowing some weapons to travel further
– Has better vertical performance
– Has better Cockpit visibility
– Has Ejection Seats
– Has M/RWR and CMDS
– Smaller aircraft physically, and thus a smaller target
– Has a Pressurized cockpit, and thus a much higher maximum operating altitude

Designs are always a compromise, and with the AT-802U it is obvious where the compromises are in terms of performance: It sacrificed speed and vertical performance for potential maneuverability and superior endurance, range, or payload. Its slow speed coupled with its lack of warning and counter measure system means it is ideal only against “low-threat” opponents, like Insurgents or Separatists firing their rifles into the sky.

But against an opponent with Surface to Air Missiles and/or radar-guided cannons, even if M/RWR and CMDS are fitted in, the AT-802U’s slow speed will still make it more vulnerable to enemy fire. Also don’t forget that the largest agricultural aircraft in the world would also make for a relatively larger target.

It is a DURABLE target with all that ballistic protection, but an aircraft can only take so much punishment after which it will start falling out of the sky. IMHO, the AT-802U is better for Law Enforcement or Special Mission/Forces use (like what UAE is using them for) rather than an attack aircraft, and it will definitely excel in those roles. Meanwhile, for the PAF, IMHO the A-29B Super Tucano will be better as it will be more survivable against “external threats”. Yes, I meant China.

An AT-802U in Flight. Photo courtesy of AV8PIX Christopher Ebdon thru Flickr
An AT-802U in Flight. Photo courtesy of AV8PIX Christopher Ebdon thru Flickr

GLOSSARY

  • WING LOADING = is the amount of weight the wing supports during flight, and is expressed in weight per area, or in the metric system, kg/m^2. This is computed by: (Wing Area divided by Weight).
    http://en.wikipedia.org/wiki/Wing_loading

  • POWER TO WEIGHT RATIO = means how much power the aircraft has compared to its weight, and is expressed by a simple number. This is computed by: (The maximum power of the aircraft’s engine divided by weight).
    http://en.wikipedia.org/wiki/Thrust_to_weight_ratio

  • INTERNAL FUEL FRACTION = is the weight of the internal fuel the aircraft compared to its maximum take-off weight, and is expressed by a simple number. Formula used is: (Maximum internal fuel capacity divided by maximum take off weight). http://en.wikipedia.org/wiki/Fuel_fraction

SOURCES:

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22 thoughts on “The AT-802U Air Tractor versus the A-29B Super Tucano”

  1. How can 2 x.50 caliber and 5 hard points be advantageous to 11 hard points?
    The AT-802u starts at 3 million up to 10million tops as fully loaded with all the bells and whistle. At $400 cost per hour vs. the almost $800 of a ST I think that is a glaring disparity. This ugly bird (AT-802u) can land in the rough fields of Balabac Island all the way to Itbayat. Very minimal maintenance is required.
    As a CAS aircraft against the Abus and NPA this is perfect and cost effective. You can probably buy a minimalist variant and get 3 for the price of a Super Tucano. At the same time it could be your hightech platform for PGM’s using the latest such as 100km Mini-talon or the cheap Cirit 2.75. Why spend 21m when you can buy and get things accomplished at half or one third the price?
    Against China, please, neither the ST can survive or any prop aircraft against and MRF.

    1. Because gun pods will always create more drag than internal guns, that’s why. As for survivability, naturally a bigger, slower aircraft with no warning or countermeasure systems will be LESS survivable than a smaller, faster aircraft with warning and counter measure systems.

      As for PGMs, on one hand you insist on the AT-802U’s cheap price and operating cost, but on the other hand you insist on using PGMs? Sure, these smaller PGMs are less expensive than bigger PGMs, but in the end they are still more expensive than conventional munitions. If that’s your opinion, fine with me, just don’t keep shoving it down our throats.

  2. Though its drag deficiency is true, having more hard points simply offers more flexibility and lethality coupled with its ability to carry twice a much than the Super Tucano.Those Mini PGM’s I mentioned I’m just pointing its flexibility depending on its mission from plain jane to fully loaded with high tech system. When AFP used PGM’s in an Abu Sayyaf lair in Sulu, we know what happened in an instant. It was done and over with. Expensive, yes maybe more. But you cannot be more precise and accurate to get the job done. That can strike fear if used appropriately. The Philippine scenario offers a perfect fit for the Air Tractor because there are no A2 threat nor surface to-air threat,therefore, the speed and its slowness than ST is negligible.
    I’m sorry if you perceived that I was shoving it down your throat. I was merely pointing out the differences between the two. Please……just take my comments with a grain of salt. It’s just an opinion. Again, I’m sorry. Keep up the good job. There are no blogs out there that offers comparisons like you do. Though I may differ sometimes, it’s just from my deficient brain.

  3. Why would you use a low cost , low intensity counterinsurgency aircraft on China? Both the Tucano & the AT-802U will not stand against Chinese warships. .The requirement is to provide air support & surveillance for the Abus , NPAs & muslim separatist. At lower cost , longer loiter time heavier load the AT-802U provides the best solution. Im sorry if it isnt as sexy as the hot Brazilian Supaer Tucano.

    1. Just because it only uses a propeller doesn’t automatically mean it is not capable against foreign troops. There are no requirements that says these are just for insurgents and separatists, the requirement is for a “Close Air Support” aircraft. As for the low price, why not stop at the AT-802U, why not go and look for even cheaper alternatives?

  4. AT-802 U would be the best CAS for COIN in Philippine setting. I think it would be crazy to use the S. Tucano against external threat. If we want a multirole CAS for COIN that will handle the naval strike role better for us to acquire the brand new MB 339 , AMX-ATA or L-159 which can be programmed to carry anti ship missiles for strike missions.

    1. I agree that ST should not be used for maritime strike.

      But the ST is still the better CAS platform. The tractor is very slow compared to the ST. It could take too long to arrive at area of operaton and provide air cover to ground troops who are battling the insurgents.

    1. We dont expect the CAS plane to land on water. This capability is not even a stated requirement as a OV-10 replacement for COIN operation. You only land on sea for resupply purposes, like in the Ayungin. And the PAF is already buying seaplanes as a separate acquisition.

      The ST can also hunt insurgents on mountains, land, or sea, most likely better than the Air tractor. It has demonstrated itself as a proven platform for hunting drug traffickers, illegal loggers, and criminals in the Amazon which has a land area bigger than our country.

      Also, the Air tractor is STILL a prototype, it is unproven except in the paper. If the purchase goes via bidding this plane cannot even participate, same as the armed Texan.

  5. We dont expect CAS to land on water but is it not an added capability to a CAS platform since we are in short supply of aircraft? UAE & Jordan is already using the AT-802 platform. The AT-802 has also been used in counter-drug operations in the USSOUTHCOM AOR by the U.S. Department of State as a delivery vehicle for herbicides and defoliants over narcotics production facilities. Soon the Yeminis will acquire their own AT-802 U provided by the US yo hunt down terrorists…

  6. It also seems that the Super Tucano will be 4 times the price of a single AT-802U. AT-802U can loiter up to 10 hrs, can carry up to 15 hard points like the a1 sky raider can land in water , can carry long range stand off weapons , armored cockpit & by the way does have an IR flare counter measures for Manpad SAMs. What more do you want? (6) ST or (24) AT-802U?

    1. We need to confirm if the price of the AT-802U is really only 25% that of a Super Tucano. And price is not the only consideration, other factors come into play also likely safety and performance. In the end, let the PhAF decide what plane they want to use …

  7. I am not sure either about the AT-802U being 25% the price of the ST. It is still a prototype. Perhaps that is the price of the old agricultural version of the air tractor.

    We should take a deeper look at price claims like this. Most of the time, start-up competitors tend to significantly price down their products against established ones, so that prospective clients can give a 2nd look at their offering. The same thing happen with armed Texan, it was supposed to be cheaper than ST. Yet, even as just 3 prototypes have been produced the price starts to go up already, roughly 70-90% of the ST.

    As far as the militaries are concerned, both local and foreign, they seem to have said that ST is actually a good priced for an established product that is already tested and proven for COIN operation.

  8. My cent: this comparison article between the AT802u and A-29 has merit in figures. However, rhk111′s rationale for maneuverability, speed and weapons flexibility are presumptuous if not outrageous.
    It must be noted that PAF is looking for CAS aircraft, not racing aircraft. And that slow speed has better virtue for CAS in non-high threat air environment. That’s why the A-10c is better CAS aircraft than F-16C or F-15E.
    Also, it must be noted that this turboprop aircraft the PAF is looking will replace the ageing OV-10s, hence, CAS with high weapons payload and flexibility, and ISR with high fuel load, loiter or better on-station time, is more appropriate, not to mention ruggedness, very low operational and procurement costs.

  9. RHK… since we a have bidding for CAS aircraft.. and Korean will join the bidding with KAI KT-1 Woongbi to offer.. does it have the chance to outclass the super tucano? Thanks more POWER!! AND MORE BLOG TOPIC!!! hehehe

    1. Are any South Korean companies joining the CAS bidding? It doesn’t look like it. At any rate, aircraft like the Woongbi or Orlik does not have any chance of matching up to the likes of the Super Tucano because the Woongbi/Orlik are basically just Trainers with rudimentary Attack Capability, whereas the ST is the other way around, an Attack Aircraft with secondary ability as Trainers. This is reflected by the fact that the ST can carry a lot more Avionics (Decoy Dispensing Systems, FLIR, etc.) and a lot more payload.

      As for topics, yeah, I am running out of topics, thanks to all these “secrecy” in the biddings, hence very little official news about them are coming out. Thank God for that Pohang procurement, at least I’ll have at least one more interesting topic to blog about …

      1. The rudimentary attack capabilities of the KAI KT-1 and AT-6B Texan II are already good enough for COIN operations. Our local rebels aren’t using tanks and stinger missiles anyway. The Super Tucano is way too much of an overkill, considering its specs, it could even be used as an ASM and A2A weapons platform. The DnD will no doubt deploy it for WPS operations.

      2. The AT-6B, yes, but not the KT-1. No FLIR and Decoy Systems, and only less than 600 kg payload on full internal fuel. If its just for the rebels, why bother with a Decoy System or PGMs at all? An aircraft with a computerized Fire Control System will allow bombing accurate enough to be as good as using PGMs … As long as the aircraft uses optimum bombing conditions, like flying as low and slow as possible …

  10. No.. I’m just speculating `IF EVER’ they will join at any chances of winning their product.. Thanks a lot 🙂

  11. When flying in a low intensity environment IOMAX’s Archangel should fare well. In Vietnam flying at 1500 to 2000 feet kept aircraft out small arms range. The 12.7mm (50 cal) machine gun could be a problem, but firing on aircraft, even the 100-120mph helicopters is tougher than you might think. Few insurgents are normally what could be called excellent gunners. Man carried missiles brought down some aircraft late in the Vietnam conflict, but just like the battle against ISIS there isn’t a great number of these weapons on the battlefield. The real issue is providing the friendly grunts with air support that can loiter long enough to support them as battlefield conditions change (often rapidly and frequently). The Toucano and Wolverine aircraft don’t carry heavy weapon loads or have long loiter times. They are both faster, but the Archangel can stay on station longer than both of them and longer than helicopter gunships and the archangel has more firepower. I would to know if it could carry a 3barrel 20mm cannon pod and fire it repeatedly without damaging the pylons or wing structure. The Archangel won’t suit the USAF. They have never likes CAS missions. I say let them have jets with massive firepower for “heavy” ground attack missions. Repeal the 1948 agreement that keeps the Army from using fixed wing aircraft for attack missions and let the Army use something like the Archangel to do their own CAS. They will support the grunts better than the USAF, because that is the only mission of aviation in the Army, support for ground forces. Let the USAF keep the skies clear of enemy aircraft and let the flying grunts support the ground forces.

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