mark18mwm Posted April 24, 2013 Share Posted April 24, 2013 I seen this on the news and thought it was interesting so here is a link to the news video. # 1&2 eng. out landing and then blowing a tire after touch down, Every one one board and plane are ok it sounds like. Not the biggest story but not one that happens all that often. I'm sure many of you guys have some far more harrowing tales. http://www.kgwn.tv/story/22059264/c-130-makes-emergency-landing-at-cheyenne-airport Quote Link to comment Share on other sites More sharing options...
SEFEGeorge Posted April 24, 2013 Share Posted April 24, 2013 Interesting. #1 seemed to be windmilling a little. Blown tire is no surprise, only emergency brakes I imagine (based on my fading memory). It'll be interesting to hear what caused the loss of 2 engines. Seem too recall that while I was at Hickam, we had a bird land with no utility system. FE was Jake Hallman. Honolulu airport was not very happy with leaving the bird sitting on the runway waiting for a tug. Quote Link to comment Share on other sites More sharing options...
Dave in WV Posted April 24, 2013 Share Posted April 24, 2013 With straight 3000 psi pressure at the brakes now and with the anti-skid inop, skidding the main tires is very easy to do. When you skid them you either flat spot them (often ruined) or blow them out. Quote Link to comment Share on other sites More sharing options...
Railrunner130 Posted April 25, 2013 Share Posted April 25, 2013 The landing itself looked very nice. My compliments to the AC on that one. I wonder how many pairs of shorts were ruined! (I can't really blame anyone, I probably would have too...!) Quote Link to comment Share on other sites More sharing options...
Sparks Posted April 25, 2013 Share Posted April 25, 2013 I remember one at Langley. The bird was making a routine landing when the anti-skid failed and brakes locked on the left main gear. Both tires blew taking the left wheel well with them. Of course this caused all kinds of excitement. Maintenence worked on that hanger queen for months putting it back together. Quote Link to comment Share on other sites More sharing options...
agarrett Posted April 25, 2013 Share Posted April 25, 2013 Looks like #1 is rotating backwards? Quote Link to comment Share on other sites More sharing options...
Dave in WV Posted April 26, 2013 Share Posted April 26, 2013 Looks like #1 is rotating backwards? Yes it is. When feathered, the prop is supposed to push back against the prop brake. Quote Link to comment Share on other sites More sharing options...
Ronc Posted April 26, 2013 Share Posted April 26, 2013 Yes it is. When feathered, the prop is supposed to push back against the prop brake. True dave it is, but I still don't believe it should rotate backwards, I wonder if something was wrong with the gearbox. Ron Quote Link to comment Share on other sites More sharing options...
BobWoods Posted April 26, 2013 Share Posted April 26, 2013 I guess they don't teach resetting the T handle to restore oil to the engine oil pumps and bumping the condition lever to air start to stop the rotation now days. Quote Link to comment Share on other sites More sharing options...
Dave in WV Posted April 26, 2013 Share Posted April 26, 2013 The prop brake isn't holding the prop. It happens sometimes with a weak prop brake but isn't supposed to. I don't know if the slow reverse rotation damages the gearbox or any engine components? Quote Link to comment Share on other sites More sharing options...
Ronc Posted April 26, 2013 Share Posted April 26, 2013 I guess they don't teach resetting the T handle to restore oil to the engine oil pumps and bumping the condition lever to air start to stop the rotation now days. Bob, Yes we still teach that the fire handle should be reset provided no fire exists, however, this only helps if the prop is turning forward. If the prop is rotating backwards the pump would also turn backwards. We also teach to slow down as much as possible usually 180 KTAS. Have never heard of the technique to change the blade angle with air start, something I will have to think about. Ron Quote Link to comment Share on other sites More sharing options...
BobWoods Posted April 27, 2013 Share Posted April 27, 2013 Ronc, Changing the blade angle so the prop rotates the correct way allows the oil pump to pump oil to the engine, this allows oil lubication and precludes one more problem, overheated engine/gearbox parts. That's what I remember being told back in '66. Quote Link to comment Share on other sites More sharing options...
agarrett Posted April 27, 2013 Share Posted April 27, 2013 Messing with the blade angle is a gamble. If you move it a little too far and the mech. pumps catch some fluid it's going to try to spin up on speed. Another technique is to go to air start for a sec and then right back to feather, I've seen this work but not 100%. Don't know the story on this but they decided to leave it alone and that may have been the best option. Longest flight I know of with a prop rotating backwards is from west of New Orleans to Hurbie. I heard later that the back of the gearbox was pretty toasty. Quote Link to comment Share on other sites More sharing options...
Dan Wilson Posted April 28, 2013 Share Posted April 28, 2013 Pilot did pretty good and made a purty landing. Had a seven minute flight in Germany that we had #1 shut down and #2 and #4 screwing up real bad, we elected to keep the other two engines running since we were on downwind. (#4 overspeed 105% and #2 underspeed 93%) Quote Link to comment Share on other sites More sharing options...
agarrett Posted April 29, 2013 Share Posted April 29, 2013 Pilot did pretty good and made a purty landing. Had a seven minute flight in Germany that we had #1 shut down and #2 and #4 screwing up real bad, we elected to keep the other two engines running since we were on downwind. (#4 overspeed 105% and #2 underspeed 93%) seven minutes can be a long time, eh Dan? Quote Link to comment Share on other sites More sharing options...
dinahmoehumm Posted April 30, 2013 Share Posted April 30, 2013 Bob, Yes we still teach that the fire handle should be reset provided no fire exists, however, this only helps if the prop is turning forward. If the prop is rotating backwards the pump would also turn backwards. We also teach to slow down as much as possible usually 180 KTAS. Have never heard of the technique to change the blade angle with air start, something I will have to think about. Ron An equally important question to ask is if #1 was decoupled or not. If so, good. If not, bad. Coupled drag = bad, decoupled drag, while not good, is better than bad (See: coupled drag = bad). I'm sure the crew reset the fire handle (as long as no indication of a fire existed). It's a good bet that #1 in this case was decoupled, and had been windmilling on NTS prior to decoupling. The fact that it was spinning backwards tells me that prop brake failed, but that's when our old buddy the safety coupling comes out to play, and suddenly your bad day isn't quite as bad as it was a second ago. That's at least how I remember it was supposed to work, I think... Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted April 30, 2013 Share Posted April 30, 2013 I do not think it was decoupled it was spinning too slow...it was feathered so no drag. Also the prop would have to "drive" the engine with a lot of force in order to decouple; not something I could see happening in the case it looks normal only with a weak prop brake. So Flaps 50%? Is that standard? I would guess they would have been cranked or positioned prior to the second engine shutdown. Also seemed FAST to me but it may be a camera angle thing... The Flaps being at 50% is a surprise to me... Quote Link to comment Share on other sites More sharing options...
RavenFE Posted May 1, 2013 Share Posted May 1, 2013 No word through channels yet as to why they ended up with #1 & #2 shutdown. Flaps looks like maybe 20%, possibly to get high rudder boost from Booster Hyd system. Pulling Wing Flap CB and setting handle to get HRB seems a better solution but again don't know all the info. Yes he may have been a little fast on touchdown; Vmca 2 Engine high boost would be about 145 and normal (low) 185 Quote Link to comment Share on other sites More sharing options...
agarrett Posted May 1, 2013 Share Posted May 1, 2013 (edited) #1 prop leak #2 oil leak. From the crew, on facebook Flaps must have been where they were before the 2nd engine was shut down otherwise they would'nt move. Edited May 1, 2013 by agarrett flaps Quote Link to comment Share on other sites More sharing options...
dinahmoehumm Posted May 1, 2013 Share Posted May 1, 2013 I do not think it was decoupled it was spinning too slow...it was feathered so no drag. Also the prop would have to "drive" the engine with a lot of force in order to decouple; not something I could see happening in the case it looks normal only with a weak prop brake. So Flaps 50%? Is that standard? I would guess they would have been cranked or positioned prior to the second engine shutdown. Also seemed FAST to me but it may be a camera angle thing... The Flaps being at 50% is a surprise to me... Hate to quibble with you NATOPS, but it was spinning slowly because the airplane was slowing down as it landed. A windmilling prop (assuming the safety coupling has decoupled) is going to spin at an RPM commensurate with the airspeed of the airplane. Faster airspeed = faster windmilling prop RPM. Slower airspeed = slower windmilling prop RPM. As to your statement that "it was feathered so no drag," well, that's not exactly right either. A feathered prop that hasn't decoupled creates quite a bit of drag actually, and the 1-1 makes note of that (higher VMCAs). That's why the safety coupling exists, for that very reason. The safety coupling's location (between the torquemeter and the pinion input gear in the RGB) is set to decouple at a negative torque value of 6,000 lbs. (if I remember correctly). It gets to that negative torque rating precisely because the prop IS "driving" the engine, not the other way around (normal operation). You would have to have two component failures in the same RGB (prop brake and safety coupling) for the prop to be both windmilling AND remain coupled. Even at a reasonably slow airpeed, a windmilling prop is creating enough negative torque to cause the safety coupling to do it's thing. Not trying to be a d*ck, just providing some clarity. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted May 1, 2013 Share Posted May 1, 2013 Quibble away; I get the airspeed relationship. If you look at the blade angle it is pretty close to feather (at least 86 degrees) so that is why I said no drag... The VMCA is based on a prop that did not feather IE: FLAT MAX drag; not feathered rotating backwards... If you look the prop in this case it is feathered, to the point it is rotating backwards... FYI, You could have no failures in the RGB and have a "coupled windmilling prop". Just for clarity the prop brake is internal (RGB) the Safety coupling is external and not "part of the RGB". Quote Link to comment Share on other sites More sharing options...
US Herk Posted May 1, 2013 Share Posted May 1, 2013 Definitely both feathered and likely just a weak prop brake. When I had them on FCFs, I'd slow down and see if they stopped. Quite often, once stopped, you could speed back up and the brake would hold - of course, I wouldn't do something like that with two out! Flaps may indeed be at 20%. With the Fowler design, plenty of lift with less drag penalty (there is always some) moving them back - it's a lesser used technique and seems to come and go in and out of favor. Depending on their weight, it may not be any real penalty at all... Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted May 1, 2013 Share Posted May 1, 2013 Yea I still think they (flaps) are at 50% I say this due to the "downward movement" they have made. Look at the ailerons as it "flies" by and you can see the flaps are half way; if at 20% not that much downward movement. Think increased lift without the drag penalty of 50% but no 20% landing speeds so using 0% speeds means your fast... Quote Link to comment Share on other sites More sharing options...
SEFEGeorge Posted May 1, 2013 Share Posted May 1, 2013 Seem to recall that we used to show a technique of putting the flaps at 20% to get a little extra lift and high rudder boost when needed. Quote Link to comment Share on other sites More sharing options...
RavenFE Posted May 2, 2013 Share Posted May 2, 2013 Any other secrets revealed on the crews Facebook page? Quote Link to comment Share on other sites More sharing options...
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