Metro tricks of the trade.

[SA227driver]

Now I just have to deal with freak Florida weather. At least now I have a radar that actually paints the cells before I enter them. ;-)

Kinda looks still looks like a Metro on the inside.

 

[Tommay85]

Yeesh! I think your yoke is in worse shape actually! haha I hear ya on the radar. Over the sea, it works pretty well. Approaching land, is that an island or a HUGE cluster of hell on earth?

I figure that place would be a great place for a freight hound to break into 121. The MD-XX has to be just as medieval as the crap Ameriflight flies right?

 

[JeppUpdater]

How is the NTS check done in the Metro?

Hold/ride the brakes, with speeds low push the power levers up one at a time, RPM should stabilize at 94%. All it really verifies is oil is available to the NTS system...a 'true' NTS check requires the engine to be shutdown. (Found this out when we acquired another Metro)

In our Metros on the pilot's side switch panel there is blanked out 'NTS Test' switch, no idea what it would do if it was present in any Merlins/Metros.

 

[SA227driver]

How is the NTS check done in the Metro? In the CASA it is done during start. You hold down the NTS check switch during start, and the first 20% during start up the light is out. At around 20% the light comes on indicating the NTS check is complete.

In our Metros at AMF there was no NTS check switch. We did a check after we released the start locks and on taxi out. Hey AMF guys help me here with the numbers, I've got MD80 and Airbus numbers memorized now.

We did each engine at a time, brought the RPM up to ~93% (help me out guys), noted the torque, then increased torque by 10% and note the RPM, should be between ~93.5-94.5%. This would be considered a good check. Two things were accomplished: 1.) making sure you brought the props off the start locks and 2.) verified that the NTS valve was working properly.

 

[ASpilot2be]

Hold/ride the brakes, with speeds low push the power levers up one at a time, RPM should stabilize at 94%. All it really verifies is oil is available to the NTS system...a 'true' NTS check requires the engine to be shutdown. (Found this out when we acquired another Metro)

In our Metros on the pilot's side switch panel there is blanked out 'NTS Test' switch, no idea what it would do if it was present in any Merlins/Metros.

Interesting. Thanks for the info. It is amazing how engines from the same manufacturer work so differently on each airplane.

 

[SA227driver]

Yeesh! I think your yoke is in worse shape actually! haha I hear ya on the radar. Over the sea, it works pretty well. Approaching land, is that an island or a HUGE cluster of hell on earth?

I figure that place would be a great place for a freight hound to break into 121. The MD-XX has to be just as medieval as the crap Ameriflight flies right?

With the exception of the two "glass" screens and the FMS and being a swept wing jet, it was for the most part a very east transition from the Metro.

 

[ASpilot2be]

In our Metros at AMF there was no NTS check switch. We did a check after we released the start locks and on taxi out. Hey AMF guys help me here with the numbers, I've got MD80 and Airbus numbers memorized now.

We did each engine at a time, brought the RPM up to ~93% (help me out guys), noted the torque, then increased torque by 10% and note the RPM, should be between ~93.5-94.5%. This would be considered a good check. Two things were accomplished: 1.) making sure you brought the props off the start locks and 2.) verified that the NTS valve was working properly.

Interesting. I like having switches. If we had to do that check on some of the ramps up here some interesting times would occur.

 

[SA227driver]

Interesting. I like having switches. If we had to do that check on some of the ramps up here some interesting times would occur.

Yeah, a lot of times on contaminated ramps you'd have to do it on the taxi because stationary with the parking brake set and you'd be sliding all over the ramp.

 

[Tommay85]

In our Metros at AMF there was no NTS check switch. We did a check after we released the start locks and on taxi out. Hey AMF guys help me here with the numbers, I've got MD80 and Airbus numbers memorized now.

We did each engine at a time, brought the RPM up to ~93% (help me out guys), noted the torque, then increased torque by 10% and note the RPM, should be between ~93.5-94.5%. This would be considered a good check. Two things were accomplished: 1.) making sure you brought the props off the start locks and 2.) verified that the NTS valve was working properly.

That is correct. Not sure on the NTS valve, but for sure it's checking that there's oil pressure to the system and that that governor is working correctly.

I don't know if it's correct as well, but a check airman told me that if you "accidentally" go above 94% and the governor brings it back to 94, you're good to go as well. In other words, haphazardly throw the powerlever up to 20-30 torque and if it stabilizes at 94ish percent, the check is good. Heh...

 

[ASpilot2be]

Yeah, a lot of times on contaminated ramps you'd have to do it on the taxi because stationary with the parking brake set and you'd be sliding all over the ramp.

I bet. Some of the ramps in the villages up here are awfully slick at times during the winter.

 

[jhugz]

That is correct. Not sure on the NTS valve, but for sure it's checking that there's oil pressure to the system and that that governor is working correctly.

I don't know if it's correct as well, but a check airman told me that if you "accidentally" go above 94% and the governor brings it back to 94, you're good to go as well. In other words, haphazardly throw the powerlever up to 20-30 torque and if it stabilizes at 94ish percent, the check is good. Heh...

That's the way I do the NTS check and I do it every leg. If I get the RPM's up high enough, I know I didn't get a prop off the lock. I've done this before too. A lot less embarrassing then an aborted takeoff or a go/stop/go takeoff . A NTS failure on a hot/heavy takeoff with a V1 cut, I would say your chance of surviving it is about 5%. In the sim you know it's coming, so you're ready for it, on the line you get one, after the o-crap moment, it's already to late, you're just dead. Same with a V1 cut w/ a left essential bus failure or a V1 cut with the gear solenoid lock failing. Moral of the story, if you're going to skip every preflight inspection besides one, make sure you do a NTS check.

 

[Maurus]

How is the NTS check done in the Metro? In the CASA it is done during start. You hold down the NTS check switch during start, and the first 20% during start up the light is out. At around 20% the light comes on indicating the NTS check is complete.

Run up the engine to ~94%. Add 10% torque. If the RPM does not hold you could have a bad NTS.

This isn't perfect as Maint has a more accurate test that can still show the NTS to be working regardless of the result of the above test. This is an example of a disconnect between Maint and the flight department as they had no idea what we did for our checks. This was unfortunately true with all the airframes it seemed at AMF.

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[pwa]

Here are a couple iced up metro pics. Flying into Jackson Hole, WY.

 

[spbrian]

Run up the engine to ~94%. Add 10% torque. If the RPM does not hold you could have a bad NTS.

This isn't perfect as Maint has a more accurate test that can still show the NTS to be working regardless of the result of the above test. This is an example of a disconnect between Maint and the flight department as they had no idea what we did for our checks. This was unfortunately true with all the airframes it seemed at AMF.

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It's actually a disconnect within the 331-10 engine.. The only true way to check that the NTS valve is able to function and dump prop oil hub pressure is to apply negative torque to the NTS valve itself and ensure that the NTS oil line shows a pressure rise on the output side of the NTS valve. There is no way from the pilot operation side on the -10 engine to accomplish this, so that is the "maintenance test" and it is a required test item on the task cards.. What we as pilots are able to see is that, when we increase RPM to 94% and then increase 10% torque is that with the engine stabilizing between 93.5% and 94.5% that the prop governor is able to change the pitch of the propeller, that the rigging of the prop governor is correct and also that the NTS valve is allowing oil to flow through it. A faulty test of the NTS valve at this point would be that as engine power is increased, the NTS valve would be leaking allowing prop oil to dump and the prop would go high pitch low RPM (lower than 93.5%)..

 

[Tommay85]

Here are a couple iced up metro pics. Flying into Jackson Hole, WY.
View attachment 25147
View attachment 25146

I like a really messy wing. Got any pics of that?

 

[pwa]

haha no.... We did a really hard and fast decent blew the boots at the bottom pretty much cleared off the wings. Sorry

 

[CoffeeIcePapers]

I passed my type ride today. Thanks for the info.

 

[Tommay85]

I passed my type ride today. Thanks for the info.

Congrats! Welcome to the secret club!

 

[spbrian]

That's the way I do the NTS check and I do it every leg. If I get the RPM's up high enough, I know I didn't get a prop off the lock. I've done this before too. A lot less embarrassing then an aborted takeoff or a go/stop/go takeoff . A NTS failure on a hot/heavy takeoff with a V1 cut, I would say your chance of surviving it is about 5%. In the sim you know it's coming, so you're ready for it, on the line you get one, after the o-crap moment, it's already to late, you're just dead. Same with a V1 cut w/ a left essential bus failure or a V1 cut with the gear solenoid lock failing. Moral of the story, if you're going to skip every preflight inspection besides one, make sure you do a NTS check.

That old V1 cut with a left essential bus failure is not a realistic scenario anymore... Prior to the re-design and re-wiring of the aircraft via A.D. this was a true failure point, that as whatever failed engine was spooling down the generators would fall below their "generator" point and with the relay's still closed (nothing commanding them open) would turn into starters as the voltage dropped... This would cause the starter/generator on the failed engine to begin turning and as the propeller started to feather the load on the starter would increase above the 325 amp current limiter blowing it out... The old wiring diagram was left and right starter directly powered their respective eseential bus's through the 225 amp CL's and a feeder line. Another feeder line connected this feeder directly to the battery bus which fed directly to the other engines feeder line...

In essence, the left engine non-ntsing failure with the left essential bus failure is just something that instructors do for giggles.

 

[Tommay85]

In essence, the left engine non-ntsing failure with the left essential bus failure is just something that instructors do for giggles.

I thought it was fun! But I'm sick in the head like that...