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Alpha Kilo

Help the Iraqi C-130J crew

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Excuse my ignorance (I fly small pointy things).....

If you want a speed brake or lower idle, and you have variable pitch props, why can't you feather and/or slightly reverse them?

Yeah, feather puts the blade angles basically parallel to the wind, giving you an almost zero-drag configuration, which is quite the opposite of a speed brake.

Going into reverse in flight is a good option, and it will get you down in a hurry......in the simulator only! I have done it a few times. Ha.

I think the problem with Ground Idle or Reverse in flight is that there is no guarantee that all 4 engines will go from Alpha (flight range) to Beta (ground range) at the same time and at the same rate. There is a mechanical/hydraulic stop in the propeller unit that must move to go from the flight to the ground range, and if one engine goes into ground range before the others, you get massive asymmetrical thrust and possible "loss of the airplane," is I believe how the Dash 1 phrases it. It also says this can cause "extreme propeller overspeed." So basically, it is not designed to be in ground or reverse in flight.

Back in the day, before all this 7.0 and 8.0 gibberish (in the early 5. something days), a crew accidentally had two engines pulled into the ground range in flight. It had something to do with the way his hand/wrist was resting on the throttles and had somehow pulled the two of them back. When they slowed to the proper speed, the FADEC put one of those engines into the ground range, followed by the second one a few seconds later. I think they recovered the airplane only about 1000 feet above the ground.

Poorly designed, slow responding AP, ATS. Why did they not redesign the gear so you can actually stop in a turn? Why did they not put temp monitors on the brakes? Why pull CBs as a regular checklist item? Why reset systems (FADEC, NIU, etc) as a regular checklist item. HINT: Poor design. Why design a HOTEL mode without a method of cooling the engines (or the ability to run hydraulics)? How is that vibration issue in the cargo compartment affect us in the long term?

Dang, that really succinctly sums up all of the problems of this bird. All that shit has been a problem for over a decade now, and I agree with you - there is no excuse for that crap now. My only nitpick on your paragraph: why would you need utility hydraulics in HOTEL mode while offloading/onloading? You have good brake hydraulics. The very nature of HOTEL mode brings the torque produced down to about zero, which is part of the reason why there is no torque for the hydraulic pumps.

A brake temp monitor system could have been such an easy fix. Of all the years we have been doing assault landings in these things, you would have thought they would have put one in. Let's pull out the 1-1instead and run some charts! I believe the C-17 has a system for brake temps.

Here's a great scenario - you are planning on doing multiple assaults to a real assault 3000' training zone. On your first one, you "test the brakes" with about a 3-4 second application. You turn around and are facing the 3000' strip in front of you, prepared for takeoff. How much brake energy do you have left for a high speed abort in that situation before you get hot brakes?? If I recall, there are no charts for a situation like that, nor does the BE number in the box help you because it did not take into account that you just did a partially braked assault landing 30 seconds earlier.

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Here's a great scenario - you are planning on doing multiple assaults to a real assault 3000' training zone. On your first one, you "test the brakes" with about a 3-4 second application. You turn around and are facing the 3000' strip in front of you, prepared for takeoff. How much brake energy do you have left for a high speed abort in that situation before you get hot brakes?? If I recall, there are no charts for a situation like that, nor does the BE number in the box help you because it did not take into account that you just did a partially braked assault landing 30 seconds earlier.

Have the new carbon fiber brakes gotten to the AMC side of the house yet? We have them over here on the dark side and they're probably the best new mod I've seen put on the airplane. They're almost impossible to overheat, vastly improved efficiency over the old brakes. We currently don't know how good they are because AFSOC won't pay to rewrite the 1-1 so we're using new brakes on the old data set; all the same they're still awesome. Also, they're not very functional when they're cold; you have ride them during taxi to warm them up otherwise you can't do an engine run or static takeoff with all four at 1010, the airplane starts creeping. Was wondering what everyone else thought of them, sorry for the thread derail.

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they're not very functional when they're cold; you have ride them during taxi to warm them up otherwise you can't do an engine run or static takeoff with all four at 1010, the airplane starts creeping. Was wondering what everyone else thought of them, sorry for the thread derail.

Do what?

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Do what?

You shouldn't need to do that. The new brakes need no warm up - creeping on engine run indicates bubbles in the hydro system. If MX bleeds them properly (I understand it is a different procedure than the old brakes needed), they should work without requiring any drag on taxi.

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Sounds funny coming from a herk guy but.... a speed brake.

Flaps, cross control and NTS.

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N/A in the J

You mean the engineer has nothing to fuss about during decent?.......oh wait..

I was just putting a little legacy humor in a Jay thread

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You mean the engineer has nothing to fuss about during decent?.......oh wait..

I was just putting a little legacy humor in a Jay thread

Not just a J thing...none of the free turbine designs require NTS because in those engines, the prop is not directly connected to the compressor and turbine shaft.

You can freely spin a prop on the AE2100, PT6 and other engines and the only thing turning inside the motor is the power turbine wheel.

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You shouldn't need to do that. The new brakes need no warm up - creeping on engine run indicates bubbles in the hydro system. If MX bleeds them properly (I understand it is a different procedure than the old brakes needed), they should work without requiring any drag on taxi.

Interesting, thanks for the info. I know several guys in my plane that have experienced this, might be worth a talk with Mx to see what procedures they're employing to bleed down the brakes. Might be an issue with the fact that some of our birds have the new brakes and some have the old ones, Mx might be applying the same procedure across the fleet without accounting for which tail has what. Once again thanks, this just recently happened to me last week on a TDY up north, before that I'd never had a problem with them.

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The part about increasing RPM is true on legacy Herks with the direct-drive T56 turboshaft, but not on the free-turbine AE2100s.

I guess I was trying to describe a pitch-controlable hypothetical-region between Idle and feather (obvious some safe gaurds in place to prevent my hyperbole). But, the DASH-1 does have a warning specifically addressing operation below flight idle (another hypothetical use in flight), about extreme propeller overspeed leading to loss of aircraft.

My only nitpick on your paragraph: why would you need utility hydraulics in HOTEL mode while offloading/onloading? You have good brake hydraulics. The very nature of HOTEL mode brings the torque produced down to about zero, which is part of the reason why there is no torque for the hydraulic pumps.

Valid... I'm a pessimest, I think it's possible (however remote) for a tired-crew to screw it up... perhaps you shutdown #2, forget to turn on the aux, unfamiliar field, land, turn off, tower tells you to minimize air flow over the dirt for the fighters, hotel mode #1 and #4, bad day.

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Every TProp flight manual that I've ever seen has a prohibition against going below flight idle while in flight. But pilots do it (skydiver-drivers) and it has happened.

Some airplanes are said to be more docile and forgiving (Twin Otter, Porter), others not so much: a C90 will swap ends--documented at least once that I know of (Hawaii skydiver mishap).

As Tonka alluded to, it's a question of whether the engine is actually at flight idle, which for most designs, has the prop at the low pitch stop (no longer in NTS, in the case of direct drive engines).

I witnessed a direct-drive (TPE331) go into full reverse in flight (control malfunction), but it didn't overspeed as it was at low airspeed, as opposed to:

A number of years ago, an American Eagle crew tried to put both engines of their Saab 340 in beta (reverse) while airborne to lose altitude due to being too high on descent into Baton Rouge LA. Both motors flamed out and they dead-sticked it into New Roads, LA.

who were in a high speed descent at the time, resulting in the overspeed condition (158% on one of the motors).

By the same reasoning, even with a free turbine design, unless there is some mechanical or logical control stop to selecting beta in flight, then yes, you will definitely overspeed the hell out of the prop/gearbox/power turbine if beta is selected when the prop isn't at it's lowest angle to begin with (rpm's winding back from full)--the prop would have to drive through much higher speed-angles before getting to the beta range, resulting in a transient overspeed before arriving at a flat pitch.

Someday they might design an airplane and/or engine with that capability; maybe the A400 wants to be like it's larger C17 brethren... Till then, selecting beta in flight remains squarely in the "stupid pilot tricks" category.

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You shouldn't need to do that. The new brakes need no warm up - creeping on engine run indicates bubbles in the hydro system. If MX bleeds them properly (I understand it is a different procedure than the old brakes needed), they should work without requiring any drag on taxi.

Um yeah, creeping shouldn't happen at all. Last year we took one of the first legacys on the active side outfitted with the carbon brakes and it did the same thing with the pilot and co standing on the brakes. Immediately took it back to mx. I would agree they become MORE effective once warmed up but not required to do a t/o power run up.

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You shouldn't need to do that. The new brakes need no warm up - creeping on engine run indicates bubbles in the hydro system. If MX bleeds them properly (I understand it is a different procedure than the old brakes needed), they should work without requiring any drag on taxi.

Hmmm...We've had a lot of the "new brakes" creep on initial static takeoffs. Once they're heated, they seem to work better.

The brake temp gauge has been discussed and I'm not sure of where it is now. My understanding is that it could be a fairly easy mod (especially with the new brake systems), if the gauge is stand-alone and not hooked into any MC.

I've also heard ideas kicked around regarding the J and slowing down. It's been years, but I think there was some ability to reschedule the props so that FLT Idle could be a slight negative HP. It's all about the $. If the users want it and will pay, LH will do it.

The J that got the throttles in the ground range in flight- They were at Max reverse for 7 minutes (long descent). Once the plane slowed thru 145 KTAS, the 4 motors began to move towards max reverse asymmetrically. They came really close to flaming out all four as the overspeeds were at ~108.4 and I think the motor shuts down at 108.6. I knew the crew and the IP that recovered the plane. The IP is good shit. Now, we get all kinds of warnings if the throttles come over the gate in flight.

There's still a lot of J hate, I find it funny. It's a pretty damn capable and fun to fly airplane.

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The brake temp gauge has been discussed and I'm not sure of where it is now. My understanding is that it could be a fairly easy mod (especially with the new brake systems), if the gauge is stand-alone and not hooked into any MC.

We'll make these Js look like the E/Hs with gauges/displays everywhere in no time!

On a serious note, a brake temp gauge would be the heat (no pun intended).

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"I've also heard ideas kicked around regarding the J and slowing down. It's been years, but I think there was some ability to reschedule the props so that FLT Idle could be a slight negative HP. It's all about the $. If the users want it and will pay, LH will do "

This system is called "steep descent mode". Used it on the C-27J, we could do a spiral-down from 10,000ft, one turn to a full stop landing.

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"I've also heard ideas kicked around regarding the J and slowing down. It's been years, but I think there was some ability to reschedule the props so that FLT Idle could be a slight negative HP. It's all about the $. If the users want it and will pay, LH will do "

This system is called "steep descent mode". Used it on the C-27J, we could do a spiral-down from 10,000ft, one turn to a full stop landing.

Wow. That's impressive.

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That's the only thing that I can think of, and those are pretty minor and easy to mitigate in my opinion.

Okay, so to which issues are you referring? Not trying to start an argument, I'm just genuinely curious. I don't know of many issues, other than those already discussed and the HUD in NVIS mode. I've always thought those were pretty minor and easily mitigated.

I've always thought altering some programming code was pretty minor and easily accomplished.

The stuff that needs to be changed isn't controlling the engines or flight controls or anything like that, it's essentially just making the calculator work correctly. Changing a + sign to a - sign shouldn't cost the AF anything, but I'm guessing the reason that it isn't fixed is because the AF refuses to pay Lockheed to fix a defective product because it's a minor and easily mitigated defect..

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I was told that the FMS/mission computer is "closed" off after it is compiled. Then it is tested by Lockheed (or Honeywell) for weeks/months in every possible scenario to make it is airworthy before being given to the FAA to do similar testing and get recertified. This, sources tell me, costs $1-3 million. So whether it is a block upgrade or changing a + sign to a - sign, they still have to get the entire computer tested and certified again (to include flight testing) before it can be put back on the road again. That's why they won't fix small things like that.

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Isn't Thales awesome?

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