In a video report Thursday about Tanker 41, “the latest weapon in the firefighting arsenal”, Neptune’s BAe-146 air tanker is described by the news reader and text on the screen (above) as having a “31,000 gallon tank”. That figure is off by a factor of 10 — they missed it by over 28,000 gallons. T41 can carry just under 3,000 gallons, maximum, and usually carries less due to density altitude limitations. If the 31,000 number was meant to be pounds instead of gallons, at 9 pounds per gallon for retardant it would still overstate the capacity by at least 400 gallons.
The air tankers that come closest to carrying 31,000 gallons are the 747 with 20,000 gallons, and the DC-10 at 11,600 gallons. All of the others flying today have a capacity of 3,000 gallons or less. The P2Vs usually carry less than 2,000. Coulson’s C-130Q that was awarded a contract this week will always carry 3,500 gallons when it begins dropping on fires in a few months.
The video shows T41 dropping on the Powerhouse Fire north of Los Angeles. The second time they show the drop near the end of the video, the news reader did not mention how the volume of the retardant trailed off at the end. The two BAe-146s have been criticized for having a consistent drop pattern for only the first 2,400 to 2,500 gallons, while the remaining 500 to 600 gallons dribbles out. Neptune has said they are outfitting their third and fourth BAe-146s this summer with an improved tank design which will fix some of the bugs with the tanking system. Then next winter they will modify the tanks in the first two BAe-146s, T40 and T41.
I watched some of the aerial firefighting Thursday while it was being streamed live, and saw an air tanker drop unlike any I have seen before. The same air tanker, T41, made two separate drops on the same pass. The ridgetop target was not straight. It had two straight sections but had an oxbow in the middle. The ridge was too crooked for the aircraft to make two sharp turns and treat the entire ridge in one long drop, so it flew a straight line and dropped maybe 1,000 gallons on the first straight section, stopped dropping while it passed by the crooked section of ridgetop, then when it was over the second straight section, opened the doors again and dropped another 1,000 gallons or so. Either T41 or another air tanker probably came back later and treated the oxbow section skipped before.
As for maximum altitude, max dif for the fuse is 6.7 psi, proof on build 9.4 psi, 31,000ft being a typical limitation for a later model 146.The aircraft will quite happily fly higher, but the practical problem then becomes speed as at .72 VMO you tend to be a bit slow for everything else operating at the higher altitudes.
The 146 /RJ does indeed have squat switch enabled lift spoilers,and roll spoilers on the wing.It also has enormous speed brakes on the rear fuse that can be operated through out the flight envelope without restriction.
Your right about the B 17 as an air tanker. About half the B 17’s modified as tankers where lost on fire missions. If you could taxi it (B 17) you could probably fly it, as long as you weren’t in a hurry to turn.
Here are a few differences between the 146 and larger airliners:
Slats: The 146 lacks Leading Edge Wing Slats. The DC9-10 has no slats, either, and is much more susceptible to increased stall speed with contamination such as ice or surface roughness. All DC9-30 and later have slats.
Spoilers: I am puzzled why BAe chose not to make the Lift Dumpers into controllable speed brakes. It wouldn’t take that much more complexity for the flight profile flexibility they provide.
Brakes: the 146 pioneered carbon brakes because of no reversers. I once saw a 737-200 study in which brake wear increased greatly if braking above 80 knots, where the reversers are much more effective.
Max altitude: for the 146, it’s 30,000 ft. Rumor said it was because the skin is too thin to take more pressurization.
Four engine redundancy: The ALF502 has a single accessory pad: you can mount either a generator or a hydraulic pump. Mexican airline Aviacsa in 1991 had #2 engine aft section explode, taking out #1 engine. That reportedly killed the fuel supply to 3 and 4, and they landed deadstick at night at Campeche airport.
Landing: Touches down better than any other. PSA copilot in transition training at Blythe: “I just did six landings, and every one of them was better than my best MD-80 landing.”
Great to have airbrakes…
I’m surprised BAE’s didn’t come with Thrust Reversers… so it’s tough on Brakes..they heat up fast. They have to be cooled before another take off.
Not really helpul for this type of flying.
You’re right Jerome…brake temps may be a concern but probably only when a brake fan is inop. Also we are most likely not going to land loaded. There hasn’t been any tangible dialog about operating the aircraft with a combat load that you can land with, like with the S2.
Our landing speed empty is 51,000 to 65,000, dependent on fuel, and Vref range at those speeds is 93 to 106 KIAS. There’s not much brake energy required to stop the airplane at this speed unless you’re at a high elevation. Most tanker bases wont require more braking than that required during the taxi.
I was once told the 146 has as much brake capacity per axle as a B757. The B757 has 2X the axles but it is 2.6X heavier at max landing weight.
Sure, Tim, the146 can do steep approaches, but with how much stall margin? Put the nose down, and it just does not have the drag you get with Boeing and Douglas wing spoilers. Plan the 146 approach for 1.3 Vsi, then add ten knots each for a ridge line, turbulence, and for mother, and you’ll have a shallow descent. That was my experience when PSA and AirCal flew them.
Those are called Lift Dumpers, Matt, and they only pop up when triggered by the squat switch on the main gear.
Any idea why angle of attack indicators haven’t been installed in tankers? Considering the big changes in gross weight, maneuvering, and turbulence, I would think that they would be a welcome addition.
Probably just my background showing, but even when flying commercial I would have preferred an AOA over computing V speed margins for maneuvering flight and landing.
Sure would be nice!
AOAs are standard equipment on the purpose built CL-415 and have been retrofitted on most 215s and 215Ts as well as Infra Red….. but who cares about smooth air over the wing or the hot spots when flying the tree tops over hot spots? Oh yea, it’s not an airtanker, nevermind.
This not a new person replying, just change of handle from PortaPerch.
Here’s what my friend who was primary engineer for the stall warning systems on the DC-9/MD-80 series has to say: “Douglas and the airlines decided that it was unnecessary since you have AOA providing stall warning. Since the stall warning is already certified, it might be easy to develop and certify AOA using the average of the left and right alpha vanes.”
Technically, it’s not that difficult to add AOA indicators; however, satisfying the FAA requirement that it perform its intended function could require safety analysis and flight testing. You can’t just slap it on the glareshield with a placard, “For reference only.”
AOA worked pretty well for me landing on carriers, doing ground attack and in air combat maneuvering under varying G loads and asymmetric loading, not necessarily all in smooth air. I think it deserves a good relook and rethink as a primary stall margin indicator for maneuvering flight in firefighting aircraft.
My friend reminded me that the DC-9 has optional dual Speed Command computers that take AOA vane angle buffered by flap discretes, and display a pointer on a Fast-Slow scale on the ADI in takeoff, approach, and go around modes. This function was integrated into the flight guidance system in the DC-10 and later planes. It’s there for drops if there is no overriding reason not to select Approach mode, and then the pilot can fly any AOA on the F-S scale.
It would be nice to know if the 10 Tanker, MD-87 or 146 pilots have tried it.
I agree with you that it can’t compete with anything that has lift spoilers all the way out, but what airplane would 150′ off the ground? To say it descends shallow is just plain wrong. In fact, the tanker pilot that did the fire simulation tests with BAE has more experience than any active tanker pilot and he was actually shocked at how well the airplane performed going downhill. And though I haven’t fought fire with the airplane yet, I do have a few thousand hours in it and have a pretty good idea what it’s limitations are.
Talk to any Neptune pilot and they will tell you how wonderful the airplane handles in the fire environment…though you have to remember they’re coming from a P2 and almost anything, except for maybe a B17, handles better than it.
Tim, I’ll defer to your far greater recent and hands-on experience on this..
They have been hitting this fire hard from the air. The Ramp at Fox looked crazy this afternoon. Tankers 73, 74, 76, 78, 05, 07, 41 and 48. Tanker 76 did go out of service do to some type of a problem and returned to Porterville. PortaPerch just a heads up the 146s do in fact have wing spoilers. I watched 41 deploy them after landing more than once today. I am pretty sure that they are only used for landing. Hopefully one of the 146 experts that visit this site can confirm that.
PortaPerch is correct Matt…the spoilers on the 146 are not flight spoilers only ground spoilers which require 2 of 3 squat switches indicating weight on wheels, and the lift spoiler handle selected out. Those aircraft with auto spoilers, a 33 kt wheel speed signal replaces the lift spoiler selection by the pilot.
Thanks for clearing that up Tim. I look forward to seeing more 146s on fires in the future.
I noticed the tail-mounted airbrake deployed on the Powerhouse fire drops. That’s all the 146 has to steepen a descent. It lacks wing spoilers like DC jets have, as may have been deployed on the DC-10 in its nose-down descent you pictured not long ago. When first put in service with PSA, Pacific Southwest Airlines, the 146 high flight idle prevented it from making the fast, steep approaches from altitude that was the norm for airliners. They later reduced flight idle thrust, but it still required being slow to achieve a normal descent.
It will be something to watch over terrain where a steep descent is needed. I expect there will be go-arounds, or drops from too high above the terrain.
Speaking of the tail-mounted air brakes, when the video was being streamed live from a helicopter, the pilot or reporter on board saw them deploy and said the retardant was going to come out of the rear — the tail of the BAe-146. Of course he was incorrect.
I’m not sure about the capabilities of the DC10, but I can fully assure you that the BAe146 and Avro RJs have no problems descending steeply. There’s a reason why Air Wisconsin and Mesaba Airlines had specifically designed circling approaches to runway 33 in Aspen that required a very steep final approach, and it’s called the 146.
Extensive fire simulation flight tests we’re done by Minden in cooperation with BAE…the airplane far exceeds IAB requirements for down-hill drops, and is certainly more capable than a P2 with a lift-spoiler mod.