USN HT's a calamity

[RobLyman]

Avionics and flying in the rain... anybody remember how the AFCS computer would crap out from water intrusion in the avionics bay in the 60? According to legend, the Spanish had modified their 60 fleet by adding a simple splash pan made out of sheet metal. The problem went away, then we copied that idea (after several years of tolerating the problem and getting lots of practice flying stab off IMC).

The 60R and S are aging enough now that a lot of them are mid-life. I bet they have some nice surprises in store.

I've had an audio amp crap out in a T-6 after a big rainstorm (loud screeching and the only thing you can do is shut it off, which also disables one of your radios and makes the other one really really quiet). So it's not only an old or aged airframe problem. Actually had a few of those amps go like that...

Regarding autos and the different flight characteristics of the fleet helicopters- for a long time practice autos in the 60 were to a 10-20' hover since the prevailing wisdom at the RAGs was you'd want to do a 0-0 into the water. There was also a bizarre procedure to not let rotor inertia build in the flare, which is aerodynamically a terrible idea for a low inertia rotor system. The idea to maintain Nr at 100-105% in the flare was a relic of an early, long ago replaced version of the electronic engine controls that would result in a delayed spool up if you let Nr build too high. Finally that got changed in about 2010~ish when all four 60 type wing commodores signed a big instruction on autorotations in the 60. That instruction had a long, painful read about theory and practice, but it had actual, up to date science and reason in it- mostly because of the efforts of one of those commodores. And it made everybody stop trying for the simulated 0-0/practice auto to a 10' hover since the 60 is quite survivable in a water impact with nominal forward speed, run on autos to a runway just make more sense if you ever have to do one for real, and besides, the practice autos to a 10' hover had bent too many tail stingers and stabs over the years. Those were a couple of key points that the fleet had been doing wrong for a long time. Think about that for a minute.

The flare and touchdown in the flight school autos in the 57 could stand to be fine tuned to be a bit more like the revised 60 procedure. But the revisions to the 60 auto made it more like the flight school auto was all along. Food for thought.

@HokiePilot, thanks for pointing out thing about the glideslope bar on the 57 HSI being disabled when you freeze the card by pulling the HSI breaker. I knew that but it's been so long I'd forgotten.

Morals of the stories here are critical thinking, prevailing wisdom, and bureaucracy.

Interesting, because:
1) I still see Seahawks doing the 0/0 autos at Cecil
2) Sometimes I can't for the life of me get Army Blackhawk pilots to do an auto with less than 30 kts ground speed at the bottom. I talked to an IP from Rucker and they said matter of factly, "We don't let them use more than 15 degrees nose up. You'll lose sight of your landing spot." One pilot, when I demonstrated one with close to zero ground speed said, "Whoa, that's one of those Navy autos."

Regarding rotor inertia, checking/controlling Nr in the flare makes the flare more effective. ie It bleeds off more airspeed and rate of descent. With the M model wide chord blades it is even more noticeable. It also makes a good teaching point on aerodynamics.

As you said, it has to be survivable. Greater than 30 kts becomes unsafe. So is 0 kts with too high of a rate of decent.

These kinds of discussions should be happening amongst those making the decisions about training and aircraft procurement.

My word of advice:

Don't copy or discount what another service is doing without looking closer. What works in one training model may not work in another, at least without some modification. You've got to understand what you are looking at.

FWIW: I am TOTALLY familiar with the AFCS and rain issue. Thankfully the Blackhawk does a little better job of component placement. On the other hand, rain dripping down through the overhead circuit breaker panel isn't necessarily better.

 

[Randy Daytona]

Is there any scenario where the GPS sattelite network woukd ever be down??? I can't imagine it.

http://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers

 

[Uncle Fester]

http://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers

Gotta be ready for those GPS-denied environments...

 

[Gatordev]

The idea to maintain Nr at 100-105% in the flare was a relic of an early, long ago replaced version of the electronic engine controls that would result in a delayed spool up if you let Nr build too high. Finally that got changed in about 2010~ish

It's still taught not to get a crazy buildup of Nr. While the extra turns sound like a good idea, it ends up resulting in a higher rate of descent at the bottom. One of the same guys that was part of that auto review (and lurks here from time to time) was recently asked to reevaluate the concept by the RAG, and the idea is still the same. If you have a lot of turns prior to the flare, you'll end up with a higher descent rate and more turns than you can use at the pull.

Coupled with that is the "check" that Rob mentioned. I never really had it explained to me in a way that it made sense until I realized I was already doing it and it's not a "check." It's basically an O-4 auto that is a "rockandpull" rather than the original "rock..and pull."

Is there any scenario where the GPS sattelite network woukd ever be down?

Yes, and it happens regularly.

@RobLyman

You aren't seeing 0/0 autos being done at Cecil, you're seeing 25/10 (or whatever number it is that I'm supposed to know) autos being done incorrectly. A fine distinction, to be sure.

 

[Jim123]

Rob and Gator- good points about turns in the flare and lift. That instruction I was talking about has some discussion on the tradeoff between rotor inertia for the cushion/pull and managing lift by also maintaining Nr in an efficient range throughout the flare.

It's been a while since I read that instruction, let alone thought about this stuff, but as I remember the "old way" of 100-105% Nr through the flare was less than optimal, but almost overspeeding the head was also less than optimal.

edit: as it turns out, the flat pitch setting in the 57 subtly accomplishes the same tradeoff if you keep the collective bottomed during the flare- Nr builds only a bit to what is slightly faster than the most efficient Nr range. The 60 has a more aggressive flat pitch setting, mostly to be able to aggressively regain Nr (the low inertia head loses more Nr immediately after a dual engine failure).

 

[Gatordev]

I don't want to quote the whole thing since it's all Sid's words, but two points from a recent discussion between the FRSssess:

Once the ground is met, any rotor energy left over is of no value.

and

The comment from one pilot doing a full auto was "I went to pull and I was on the ground."

It's been a while since I read that instruction, but as I remember the "old way" of 100-105% Nr through the flare was less than optimal, but almost overspeeding the head was also less than optimal.

I just looked at it again and you are correct. It states 105% is optimum, but 100-110% works. Over 110% and costs out-weigh the benefits.

 

[Griz882]

http://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers

So, do SNAs still use whiz-wheels or is all the E6B stuff done on iPads?

 

[Gatordev]

So, do SNAs still use whiz-wheels or is all the E6B stuff done on iPads?

17 years ago, the only time I used the whiz wheel was to figure out the cross-wind component. Otherwise a calculator was far more precise than a piece of plastic that deformed at the sight of a sunrise.

Understanding relationships and ratios was far more valuable than understanding what all the weirdo numbers did on the CR-2. This knowledge was also applicable in the night life/social arena, as well.

 

[Randy Daytona]

So, do SNAs still use whiz-wheels or is all the E6B stuff done on iPads?

I left Whiting at the end of 2012 so I do not know what they are using now - but the Whiz Wheel needs to die (in my opinion). Timing is not used in many approaches, and if you are ever in a situation bad enough to to use timing, you should really be concentrating on flying the aircraft and not computing whether or not a 12 knot quartering wind will affect timing by 6 seconds. SNA's time would be better spent on learning how the KLN-900 can compute density altitude, RAIM availability, etc.

 

[SynixMan]

So, do SNAs still use whiz-wheels or is all the E6B stuff done on iPads?

No to whiz wheel. Primary SNAs can't use iPads. Advanced SNAs can later on.

 

[BACONATOR]

I left Whiting at the end of 2012 so I do not know what they are using now - but the Whiz Wheel needs to die (in my opinion). Timing is not used in many approaches, and if you are ever in a situation bad enough to to use timing, you should really be concentrating on flying the aircraft and not computing whether or not a 12 knot quartering wind will affect timing by 6 seconds. SNA's time would be better spent on learning how the KLN-900 can compute density altitude, RAIM availability, etc.

Not to mention the little details, like with a KLN-900, you would be foolish to use timing instead of dialing in the FAF, selecting OBS, and using distance to FAF published on most plates to determine the MAP. Except for a few approaches where the FAF is not a named fix, timing is all but dead except in a complete GPS-out, and GS-out situation, which is so rare that it would be readily apparent that you'd need to use timing when the occasion happened.

 

[AllYourBass]

I left Whiting at the end of 2012 so I do not know what they are using now - but the Whiz Wheel needs to die (in my opinion). Timing is not used in many approaches, and if you are ever in a situation bad enough to to use timing, you should really be concentrating on flying the aircraft and not computing whether or not a 12 knot quartering wind will affect timing by 6 seconds. SNA's time would be better spent on learning how the KLN-900 can compute density altitude, RAIM availability, etc.

Having flown the T-6B prior to my TH-57 time, I left Advanced with a very bare-bones knowledge of KLN-900 functionality. That thing was super capable and we used just about none of it.

 

[Griz882]

Roger...and I concur with all the above...but what happens when those pesky Russians jam the GPS? It is funny to see how even "legacy" skills are a moving target.

 

[IKE]

The 60 has a more aggressive flat pitch setting, mostly to be able to aggressively regain Nr (the low inertia head loses more Nr immediately after a dual engine failure).

I've never heard that explanation. Not saying it's wrong; just never heard it.

The 60 is NOT rigged to flat pitch at min collective. The EC-145 on the other hand is (or very close). It's very strange to us hawk pilots, because you have to pull ~50% collective just to get light on the skids. It is also super easy to overspeed during autos. One of helos the Brits use (the lynx, I think) has a collective detent, below which the blades are at negative pitch to produce a downward force and keep the helo on a ship deck.

I always figured the 60 collective rigging was set to prevent NR overspeeds with min collective, a la FCF auto checks.

 

[Randy Daytona]

Roger...and I concur with all the above...but what happens when those pesky Russians jam the GPS? It is funny to see how even "legacy" skills are a moving target.

I'll just take the 90 knot timing at the bottom of the approach plate, factor in some Kentucky windage, and hope for the best. Introductory knowledge of NDB's yes - computing timing down to the last second on a Whiz Wheel, no.