The TH-57 Perpetual Motion Machine

[busdriver]

If busdriver is still around he might be able to provide some more info, but my understanding is that the AF 60s spin at idle (the horror!) until they're ready to fly and then put the PCLs to FLY. The whole time the crew chief (or FE or mechanic or whatever the AF calls him) is on a long cord walking about.

Yep, I don't see an issue as long as the droop stops are in.

 

[Jim123]

Yep, I don't see an issue as long as the droop stops are in.

Somewhere, someone, who has never has never been exposed to different rules than their own community dogma, just had an aneurism.

 

[Pags]

Yep, I don't see an issue as long as the droop stops are in.

Which makes plenty of sense for non-shipboard ops.

 

[busdriver]

Do you guys do the leak detection checks at fly?

 

[jt71582]

Do you guys do the leak detection checks at fly?

Yeah, in the post-engagement checks, after we put the PCLs in FLY.

 

[Pags]

Do you guys do the leak detection checks at fly?

Navy h-60s used to have an FCF check where the backup tr switch was put to backup in flight. I think the army still does it, but I've never done it in the ~6yrs I've been flying the 60.

 

[busdriver]

That would explain the perception that we actually hang out in idle. After engine start we'll run through the LDI checks before running up to fly. I can see how you wouldn't want to hang around in idle on a pitching deck though.

 

[Jim123]

Navy h-60s used to have an FCF check where the backup tr switch was put to backup in flight. I think the army still does it, but I've never done it in the ~6yrs I've been flying the 60.

I can't remember if the backup pump switch was supposed to be in "ON" or "AUTO" for this check (it's been ~8 years since I've flown a 60), but a couple of my friends were in a hover practicing SAR procedures when their LDI did its thing... IIRC* the spec for the backup pump to go from off to full pressure is 0.5 seconds... meantime the tail rotor had enough time to relax its pitch somewhat and allow the aircraft to yaw ~90 degrees with a loud noise ("like the aircraft got hit by a sledgehammer" were my friend's words)... then once the tail rotor had proper hydraulic power again I think there was a bit more yaw. Note, the FCF check was nothing like this.

The guys were just happy this happened in day/VMC! Fun times.

*Some of my systems minutia might be off, but the loud noise + huge yaw kick in a coupled hover details are right.

 

[Gatordev]

I can't remember if the backup pump switch was supposed to be in "ON" or "AUTO" for this check (it's been ~8 years since I've flown a 60), but a couple of my friends were in a hover practicing SAR procedures when their LDI did its thing... IIRC* the spec for the backup pump to go from off to full pressure is 0.5 seconds... meantime the tail rotor had enough time to relax its pitch somewhat and allow the aircraft to yaw ~90 degrees with a loud noise ("like the aircraft got hit by a sledgehammer" were my friend's words)... then once the tail rotor had proper hydraulic power again I think there was a bit more yaw. Note, the FCF check was nothing like this.

The guys were just happy this happened in day/VMC! Fun times.

*Some of my systems minutia might be off, but the loud noise + huge yaw kick in a coupled hover details are right.

As a JO, one of the very smart O-4s (one of the guys that you usually learned something every single time you flew with him...or even talked about flying with) was talking about exactly what you're talking about while in a doppler. He said that's why he would turn his pump on even if he wasn't doing hoisting. It made sense to me and others and it slowly became an unwritten SOP among most of the pilots in the squadron. Fast forward and now it's actually in Natops to do it. I guess enough people spun that they thought it was a good idea.

But one-wheel landings? Crazy talk.

Navy h-60s used to have an FCF check where the backup tr switch was put to backup in flight. I think the army still does it, but I've never done it in the ~6yrs I've been flying the 60.

We did it when I was a JO. It was definitely one of the items you'd touch on when training a FCP. "Don't do this until you're up and away."

 

[RobLyman]

As a JO, one of the very smart O-4s (one of the guys that you usually learned something every single time you flew with him...or even talked about flying with) was talking about exactly what you're talking about while in a doppler. He said that's why he would turn his pump on even if he wasn't doing hoisting. It made sense to me and others and it slowly became an unwritten SOP among most of the pilots in the squadron. Fast forward and now it's actually in Natops to do it. I guess enough people spun that they thought it was a good idea.

But one-wheel landings? Crazy talk.

We did it when I was a JO. It was definitely one of the items you'd touch on when training a FCP. "Don't do this until you're up and away."

For the Army MTF, the MTP briefs his crew, then the switch goes to B/U on the ground, the pilot checks for control before lifting off, performs left and right 45 degree turns in a hover, then goes back to NORM while in a hover.

The .5 seconds for the backup pump is for either main generator online. It is 3-5 seconds with only APU generator or external power. This is not a WOW function, it is caused by a secondary contact off of the K4 relay (which tells if either main generator is online) and the K19 relay. It determines if the depressurization valve says open to allow the backup pump to come up to speed before taking te full hydraulic load.

If you do the check incorrectly, ie go to backup in a hover, you WILL get a momentary yaw excursion in the .5 seconds it takes for the B/U pump to take the load and the #2 T/R servo to reposition to the correct position for the current flight regime. I have never had it happen to me, but it would be a LONG 3-5 seconds if for some reason your K19 relay or #2 logic module had issues. I would definitely have to change my drawers.

 

[RobLyman]

when I flew the Seahawk, I remember the NATOPS sayng "no more than one inch of collective" when shutting the rotors down. We always bottomed the collective. Does the Navy still do that, bottom the collective on shutdown?

The reason I ask is that the Army teaches to always sets 1" of collective upon startup and shutdown.

 

[Gatordev]

when I flew the Seahawk, I remember the NATOPS sayng "no more than one inch of collective" when shutting the rotors down. We always bottomed the collective. Does the Navy still do that, bottom the collective on shutdown?

The reason I ask is that the Army teaches to always sets 1" of collective upon startup and shutdown.

Still bottom it. When we went to no-rotorbrake starts, they initially told people to do the 1" because that's how the Army does it. As it turns out (so I was told), the Seahawk has a more negative pitch than a BH at full-down. The result of doing the 1" was that we started throwing anti-flaps across the line as they disintigrated. Now everything is full down, from start up to shutdown.

The negative pitch makes sense, but I'm guessing Bert would be able to confirm that.

 

[helolumpy]

The .5 seconds for the backup pump is for either main generator online. It is 3-5 seconds with only APU generator or external power. This is not a WOW function, it is caused by a secondary contact off of the K4 relay (which tells if either main generator is online) and the K19 relay. It determines if the depressurization valve says open to allow the backup pump to come up to speed before taking te full hydraulic load.

And I thought I killed those brain cells off with alcohol a long time ago...

The reason I ask is that the Army teaches to always sets 1" of collective upon startup and shutdown.

A technique I was taught as a young 60 pilot (by a TPS pilot) was to lift the collective up a little (less than 1 inch) to help seat the droops stops. The other trick was to do a small stirring motion with the cyclic while the collective was up.

I've had some pilots tell me that it will not make a difference, but I seem to have had less trouble with 'hung droops' than some of my contemporaries, so I think there must be a connection.

 

[BACONATOR]

I can't remember if the backup pump switch was supposed to be in "ON" or "AUTO" for this check (it's been ~8 years since I've flown a 60), but a couple of my friends were in a hover practicing SAR procedures when their LDI did its thing... IIRC* the spec for the backup pump to go from off to full pressure is 0.5 seconds... meantime the tail rotor had enough time to relax its pitch somewhat and allow the aircraft to yaw ~90 degrees with a loud noise ("like the aircraft got hit by a sledgehammer" were my friend's words)... then once the tail rotor had proper hydraulic power again I think there was a bit more yaw. Note, the FCF check was nothing like this.

The guys were just happy this happened in day/VMC! Fun times.

*Some of my systems minutia might be off, but the loud noise + huge yaw kick in a coupled hover details are right.

Yes, and "AUTO".

And I thought I killed those brain cells off with alcohol a long time ago...

A technique I was taught as a young 60 pilot (by a TPS pilot) was to lift the collective up a little (less than 1 inch) to help seat the droops stops. The other trick was to do a small stirring motion with the cyclic while the collective was up.

I've had some pilots tell me that it will not make a difference, but I seem to have had less trouble with 'hung droops' than some of my contemporaries, so I think there must be a connection.

Apparently this gouge is making the rounds, because I was taught this as a 2P, it works, and it wasn't a TPS guy who taught it to me.

 

[Pags]

I can't remember if the backup pump switch was supposed to be in "ON" or "AUTO" for this check (it's been ~8 years since I've flown a 60), but a couple of my friends were in a hover practicing SAR procedures when their LDI did its thing... IIRC* the spec for the backup pump to go from off to full pressure is 0.5 seconds... meantime the tail rotor had enough time to relax its pitch somewhat and allow the aircraft to yaw ~90 degrees with a loud noise ("like the aircraft got hit by a sledgehammer" were my friend's words)... then once the tail rotor had proper hydraulic power again I think there was a bit more yaw. Note, the FCF check was nothing like this.

The guys were just happy this happened in day/VMC! Fun times.

*Some of my systems minutia might be off, but the loud noise + huge yaw kick in a coupled hover details are right.

60S NATOPS says that you should expect a 20-30deg heading change if the servos switch over. Folks I know who have had it happen to them said it was just like NATOPS said.