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Naval Aircraft and AOA

SynixMan

HKG Based Artificial Excrement Pilot
pilot
Contributor
* funny secret about the T-6B natops and primary contact FTI: "1350-1500fpm at 125KIAS" translates to about 1.7nm per thousand feet, which means even though your math from 10 miles away and 8000' looks perfectly doable, in reality you'll arrive at high key about a thousand feet low. Joke's on you, students and instructors!

You can make up a bit of this in the ELP since she carries a lot more energy than you'd think with a feathered prop. I landed engine out at Summerdale (yay 4000 ft) and ended up in the paved overrun area with two blown main mounts trying to get her stopped before we went off roading. Admittedly I think I was too aggressive on the brakes, but I had a lot going on.

It was fun to talk to the JPATS program office folks since no one had landed engine out in a while.
 

jollygreen07

Professional (?) Flight Instructor
pilot
Contributor
What happened? I just had my NATOPS check this morning and we were discussing actual engine out performance being quite a bit better than what we simulate by setting 4-6%.
 

Jim123

DD-214 in hand and I'm gonna party like it's 1998
pilot
What happened? I just had my NATOPS check this morning and we were discussing actual engine out performance being quite a bit better than what we simulate by setting 4-6%.
That 4-6% torque setting is only zero thrust in the ~125 knot speed range- the propeller will make a nice airbrake if you're going a lot faster than that, and of course it'll pull you along a pretty brisk ground taxi at the other end of the range. The result is when the prop is feathered for real then that airplane floats in the flare a little more than it does during practice/simulated flameout. So if you're faced with an actual engine failure in one and going to a short~ish runway, then you've got to balance carrying extra energy to low key, just in case you misjudged the winds and your energy state, but then be ready to slip like a big dog and put it down slow and early on the runway- and not to forget that running off the end of the runway at a fast taxi speed doesn't hurt the crew and usually doesn't hurt the airplane, as long as you're not too fast.

(All of which you already know, as a second tour T-6 guy, I'm just commenting for the discussion at large.)
 

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
That 4-6% torque setting is only zero thrust in the ~125 knot speed range

It would be interesting to know if the T-34 had the same reaction, but I want to say it didn't. It was rare to practice an actual landing at simulated feather (205#), but when you did, you would definitely float down the runway unlike at idle.

@SynixMan I'd love to hear your story.
 

SynixMan

HKG Based Artificial Excrement Pilot
pilot
Contributor
I feel like I've mentioned it on here before, but:

TLDR: I pulled the engine off on an SNA and dead sticked it in from high key.

Brand new IP, instructing an Aero flight in the Pensacola South MOA. Typical late summer day, so afternoon cloud buildups but nothing crazy. Set SNA up for an easy simulated Eng Failure (for him to practice the "Eng out flare") coming out of 10k, he does his EP steps and I set 4-6% TQ to simulate engine shutdown. Dodging clouds, we get a TCAS hit approaching high key, I can't see them visually (probably busted Cessna out of Foley), I take controls from the SNA and power up and away and reset him. Second attempt, headed into high key, another TCAS hit but on the aft quarter, I give the EP, he calls for simulated shutdown, and I pull off the PCL. ?

If you've never heard the PT6 feather in flight, it's one of the most disconcerting sounds I've ever heard, followed by eerie silence, then lots of alert tones. I take controls from the SNA as we're coming through 3500 into a very nice high key, start the air restart procedures by motoring the engine, then (Very briefly) think about props coming out of feather effecting sink rate during the ELP and elect to just fly the ELP with the penguins I had left on my iceberg. Gear came down with the residual HYD pressure from motoring the engine, flew an okay-ish ELP with an overshooting crosswind and crossed the threshold around ~130KIAS with the flaps fully down and a bit high. I'll admit I was more concerned about shorting it, so probably flew it a bit tight to hit the runway with good lineup.

Flared for what seemed like an eternity to bleed off the speed and take lift off the wings to land. @Jim123 point about the physics of engine out is on point. I felt like the 4-6% simulated we did to practice was a good approximation for training. Mains touched with about 1500ft of runway (good ole Summerdale with 4k ft) + 300ft of paved over-run. Got on the brakes pretty strongly with the 1 board zooming by, locked up the mains and blew them with a few hundred left and rode the rims before stopping in the overrun. Crash truck pulls up as I'm opening the canopy, catching my breath, and pulling the seat cushion out of my asshole.

Aftermath: Two new tires/rims made it a HAZREP in terms of cost. That was it. I had a good CO who recently had a mishap doing an FPC (the TW-5 bird that had been in the hangar for 3 years as of 2019 with the "replace wing" MAF if you know it). I gave him the whole story, he laughed, congratulated me on fucking up and then doing what I was trained to do to save the SNA, myself, and the plane. Quick IP Prof with a DCON Stan IP the next day and I was back flying with SNAs with a good ready room story.

I'd say other IPs I talk to are 50/50 on the engine restart or forced landing. I tried it in the sim and it totally flies away with enough time. The JPATS engineers I talked to however said the aerodynamic modeling of the prop somewhere between feather and idle is done, so actually the sim isn't super accurate there.

On centerline until riding the rims made me a bit squirrelly:
27702

Stopped. MX came later that day with tires and towed her to parking. Flew home a week later after they verified the engine was fine.
27701
 

Meyerkord

Well-Known Member
pilot
I feel like I've mentioned it on here before, but:

TLDR: I pulled the engine off on an SNA and dead sticked it in from high key.

Brand new IP, instructing an Aero flight in the Pensacola South MOA. Typical late summer day, so afternoon cloud buildups but nothing crazy. Set SNA up for an easy simulated Eng Failure (for him to practice the "Eng out flare") coming out of 10k, he does his EP steps and I set 4-6% TQ to simulate engine shutdown. Dodging clouds, we get a TCAS hit approaching high key, I can't see them visually (probably busted Cessna out of Foley), I take controls from the SNA and power up and away and reset him. Second attempt, headed into high key, another TCAS hit but on the aft quarter, I give the EP, he calls for simulated shutdown, and I pull off the PCL. ?

If you've never heard the PT6 feather in flight, it's one of the most disconcerting sounds I've ever heard, followed by eerie silence, then lots of alert tones. I take controls from the SNA as we're coming through 3500 into a very nice high key, start the air restart procedures by motoring the engine, then (Very briefly) think about props coming out of feather effecting sink rate during the ELP and elect to just fly the ELP with the penguins I had left on my iceberg. Gear came down with the residual HYD pressure from motoring the engine, flew an okay-ish ELP with an overshooting crosswind and crossed the threshold around ~130KIAS with the flaps fully down and a bit high. I'll admit I was more concerned about shorting it, so probably flew it a bit tight to hit the runway with good lineup.

Flared for what seemed like an eternity to bleed off the speed and take lift off the wings to land. @Jim123 point about the physics of engine out is on point. I felt like the 4-6% simulated we did to practice was a good approximation for training. Mains touched with about 1500ft of runway (good ole Summerdale with 4k ft) + 300ft of paved over-run. Got on the brakes pretty strongly with the 1 board zooming by, locked up the mains and blew them with a few hundred left and rode the rims before stopping in the overrun. Crash truck pulls up as I'm opening the canopy, catching my breath, and pulling the seat cushion out of my asshole.

Aftermath: Two new tires/rims made it a HAZREP in terms of cost. That was it. I had a good CO who recently had a mishap doing an FPC (the TW-5 bird that had been in the hangar for 3 years as of 2019 with the "replace wing" MAF if you know it). I gave him the whole story, he laughed, congratulated me on fucking up and then doing what I was trained to do to save the SNA, myself, and the plane. Quick IP Prof with a DCON Stan IP the next day and I was back flying with SNAs with a good ready room story.

I'd say other IPs I talk to are 50/50 on the engine restart or forced landing. I tried it in the sim and it totally flies away with enough time. The JPATS engineers I talked to however said the aerodynamic modeling of the prop somewhere between feather and idle is done, so actually the sim isn't super accurate there.

On centerline until riding the rims made me a bit squirrelly:
View attachment 27702

Stopped. MX came later that day with tires and towed her to parking. Flew home a week later after they verified the engine was fine.
View attachment 27701
That's a damn good story, and you even have pictures! Glad you guys were able to walk away from it.
 

FinkUFreaky

Well-Known Member
pilot
What happened? I just had my NATOPS check this morning and we were discussing actual engine out performance being quite a bit better than what we simulate by setting 4-6%.
Interestingly, this was discussed at the last NATOPS Conference. To make a long boring story short, there was a NAVAIR study that said that ~15% torque may be a better approximate for engine out. I didn't have a chance to read the study, perhaps they literally meant "during the flare and rollout". Because it's clear to anyone that's flown the plane that if 15% is accurate throughout, the numbers in the PEL are all off. Basically, all that came from it is a blurb to manage energy properly added to the forced landing section [whenever the new NATOPS comes out... this conference was in APR of 2019, and I believe the new manual with changes that include minor OBOGS EP changes (will no longer matter if PCL was at idle, and turn obogs supply lever off instead of disconnecting the hose), and excessive fuel flow new EP (>800#, PEL - execute) have been coming soon for well over a year].
 

HuggyU2

Well-Known Member
None
It's been a while, but I am 99% certain the meaning was actually reversed as well in the F-16.
I’m 99% sure the USAF F-16’s have the standard AF “green donut” setup.

That’s not to say the Navy didn’t replace them with the “amber donut” on the F-16N’s.
 

MIDNJAC

is clara ship
pilot
I’m 99% sure the USAF F-16’s have the standard AF “green donut” setup.

That’s not to say the Navy didn’t replace them with the “amber donut” on the F-16N’s.

We've flown the Block 15 (A and B) for a good 15+ years now, ya old man :)

In all seriousness though, yeah could be a difference between the old birds we flew and what has been in the CAF for a very long time.
 

Jim123

DD-214 in hand and I'm gonna party like it's 1998
pilot
Interestingly, this was discussed at the last NATOPS Conference. To make a long boring story short, there was a NAVAIR study that said that ~15% torque may be a better approximate for engine out. I didn't have a chance to read the study, perhaps they literally meant "during the flare and rollout". Because it's clear to anyone that's flown the plane that if 15% is accurate throughout, the numbers in the PEL are all off. Basically, all that came from it is a blurb to manage energy properly added to the forced landing section [whenever the new NATOPS comes out... this conference was in APR of 2019, and I believe the new manual with changes that include minor OBOGS EP changes (will no longer matter if PCL was at idle, and turn obogs supply lever off instead of disconnecting the hose), and excessive fuel flow new EP (>800#, PEL - execute) have been coming soon for well over a year].
Tangent/threadjack, but did anybody finally get around to fixing the toe brake description in the systems chapter? I mean the part that says whoever pushes harder on their brake pedals is basically in control of the wheel brakes. That's true for systems with separate pilot and copilot master cylinders that are hydraulically connected (i.e. C172); it's patently incorrect and misleading for systems like in the T-6, where the pilot and copilot brake pedals are mechanically connected by pushrods and bellcranks.

If it were up to me, anybody in a position of authority who has ever resisted getting that changed should bear some pecuniary liability for every time an IP decided to "help" the student brake the airplane on a landing rollout, resulting in another blown T-6 tire. :rolleyes:
 

MIDNJAC

is clara ship
pilot
If it were up to me, anybody in a position of authority who has ever resisted getting that changed should bear some pecuniary liability for every time an IP decided to "help" the student brake the airplane on a landing rollout, resulting in another blown T-6 tire. :rolleyes:

Maybe you all should just stop blowing tires? Ok Jim? I mean we give you (they really) all the tools/pedals and you keep stomping on them. Such danger/risk. I can't wait until we have a navy that uses no brakes. Carbon savings, no climate change. Think about it
 

FinkUFreaky

Well-Known Member
pilot
Tangent/threadjack, but did anybody finally get around to fixing the toe brake description in the systems chapter? I mean the part that says whoever pushes harder on their brake pedals is basically in control of the wheel brakes. That's true for systems with separate pilot and copilot master cylinders that are hydraulically connected (i.e. C172); it's patently incorrect and misleading for systems like in the T-6, where the pilot and copilot brake pedals are mechanically connected by pushrods and bellcranks.

If it were up to me, anybody in a position of authority who has ever resisted getting that changed should bear some pecuniary liability for every time an IP decided to "help" the student brake the airplane on a landing rollout, resulting in another blown T-6 tire. :rolleyes:
Interestingly, that CAUTION still exists (in the A NATOPS, which shares much with the B and generally outside of avionics, only the C version (Army's) were basically on their own program at the conference). Never noticed it myself, I was in the NFO training business... They generally weren't on the brakes for full stops.
 
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Jim123

DD-214 in hand and I'm gonna party like it's 1998
pilot
No antiskid on the T-6?
<laughs in IP>

Nope.

Some numbers for you- the stall speed charts show between 70-90 knots (by configuration and gross weight), final is typically flown at 100 even, and touchdown in the low 90s with a flat~ish flare (flare and touchdown more like a swept wing jet with the wing "flying" than a straight wing piston greasing it on just as the wing stalls- or perhaps like a wheel landing in a taildragger, slightly fast but better controlled). There's a note or a caution about not getting on the brakes above 80 knots (because if you jump on them then you'll surely flat spot and blow a tire in no time). Best technique is to lightly drag the brakes starting at 80, then steadily increase, like squeezing a tennis ball between your foot and the pedal.

My personal "can I stop?" criteria was as long as I was right at 80 as I passed the 2,000 foot remaining marker and I began brake application right then, then I'd be able to stop without undue drama or damage (no wind, dry runway, hot day).

Another problem with those brakes was sorta self-inflicted: SOP was to basically drag the brakes during taxi, as our taxi speeds were limited. This resulted in a lot of glazed brake pads that didn't always grab well, while some airplanes had very grabby brakes. The worst ones couldn't even hold the airplane during a strong run-up. The best ones pleasantly surprise you with their effectiveness, but sometimes I think they surprise a student who is mashing the pedals. The natops has some note to the effect that the brakes are hard to modulate. Even if they were easy to modulate, most of today's generation never drove a non-ABS car in the snow or on ice.

A minor note, the airplane is slightly wobbly on its gear. That's not to say overly unstable, but on the rollout it doesn't have a firmly planted feel- crosswinds, gusts, pitch and roll inputs, and uneven braking can all make the weight shift from one wheel to another and back again. That's just one more thing that makes maximum braking more theoretical than realistically achievable.

Regarding @SynixMan 's landing, I totally get it. When Barin OLF was still a 4000' runway and I had RDO there, I'd fly a full stop practice PEL on my way in. With no wind down on the deck and a full tank of gas, energy management was a challenge. One time I quickly had to turn my intended full stop into a touch and go (more like roll and go). I touched down a bit fast and barely in the "first third" of the runway but I was rolling too fast to stop. Engine spool up eats about 500' of runway at ~80 knots (idle to max is around 3 seconds) and of course we don't have ground spoilers, so that split second change of plan is a much safer proposition than it would be in a jet. But the experience got me really focused on my own PELs, particularly during the turn to final.
 
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