Turbine DONT's

MNFlyboy said:
Ok, so I have a fair amount of time in a Caravan. Let me run this by y'all SE T-Prop drivers. I've never needed to come down in Beta or worse. Idle at a low idle condition and full prop makes for a quick descent. I suppose if one were to go into Beta, you would get a flatter pitch on the blade, but if the blade flattens out, wouldn't the prop over speed at idle and the overspeed governor would kick in? I don't think the prop would do anything at this point. The primary governor would have already adjusted the prop angle to maintain max rpm's. Putting the power lever into Beta lowers the low pitch stop. Now, lets say in the Caravan you get below 140kts and the prop rpm's start falling with the power at idle, you're on the low pitch stop. So if you went into Beta, the pitch would flatten, rpm's would increase again, I think. If the overspeed governor increases the pitch to slow rpm's and goes to an underspeed condition, but then as it sped back up again because you've got it in Beta, your prop would start going ape- on two different governors. Going into Reverse at altitude just seems nonsensical. You're telling me that you fly the airplane and put it into a position where you have to use Beta or Reverse to get down, I think there's something else that you could be doing.
Click to expand...

Never mind that beta in flight is prohibited in the manual and that it blocks all the airflow to the horizontal stab. lol
 
The last company where I flew turboprops forbid beta in flight and reverse was out of the question.

Besides, if it when into "ground fine" in flight, you're screwed. Trust your air-ground sensors?

I figure if the company doesn't want you to do "X", it's their jet, do not do "X". Because if you're busted OR break an aircraft because of willful disregard of procedures, you're out of a job and probably out of a career.
 
SpiraMirabilis said:
Wasn't there a American Eagle Saab or ATR or something that crashed and killed everyone because they went into Beta during flight? I recall, because they had to put a WoW logic so that they can't do that anymore in the Dash-8 after it happened and I learned about it in systems class.
Click to expand...

Don't know about an Eagle Saab that crashed because of it, but I know of one that had to do a forced landing because of it.

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20001206X00741&key=1

WHILE DESCENDING FOR LANDING AT BATON ROUGE, THE CAPTAIN ACTIVELY MOVED THE POWER LEVERS FROM THE FLIGHT IDLE GATE INTO THE BETA RANGE FOR UNDETERMINED REASONS. THE PROPELLERS AND ENGINES EXPERIENCED EXTREME OVERSPEED, NECESSITATING A POWER-OFF EMERGENCY LANDING AT NIGHT AND THE AIRPLANE RAN OFF THE END OF A 5,000-FT RUNWAY.
Click to expand...
 
mikecweb said:
I know we're just asking questions but the caravan slows incredibly well with flaps ten and power idle.
I never once even though about bringing it into beta.
Click to expand...

I didn't either.

If I really, really wanted to land with almost no roll out... full flaps.
 
Nark said:
I don't know what Autothrust Blue is talking about. The props are one of the best speed brakes on a turbine. Pull the power levels to idle, if you need to slow down further, bump the props up. It makes more sound, but it slows you down quickly.
If you really want to land short, you can reverse the PT6's in flight. Albeit plan for a "firm" landing and short roll out. For goodness sakes don't do this more than 3' feet from the ground.

I've found that you can fly a turbo prop and near max fwd speed to the FAF, configure and and have a stabilized approach. This is helpful when you have a date later that night...
Click to expand...

This might be one of the accidents that autothrust was talking about. High speed prolonged descent at idle and Np100% CL max. I believe they also got the power levers past the flight idle gate.

 
norcalpilot25 said:
This might be one of the accidents that autothrust was talking about. High speed prolonged descent at idle and Np100% CL max. I believe they also got the power levers past the flight idle gate.

Click to expand...

What?

Why?! WTF!!

That's what happens, man.
 
tiredcfi said:
Extra flames out the back?
Click to expand...

Just some noises that make you say "that's a funny sound for an airplane to make!". :D

I'll keep the FBO name and airport private, but one mechanic was doing in the plane doing the runup. Another mechanic and aircraft owner/pilot/whatever were standing outside in front of it. Maybe about 20 feet away. The owners guest badge fell on the ground, the wind blew it towards the airplane and the airflow around the plane did the rest.
 
UAL747400 said:
I'll keep the FBO name and airport private, but one mechanic was doing in the plane doing the runup. Another mechanic and aircraft owner/pilot/whatever were standing outside in front of it. Maybe about 20 feet away. The owners guest badge fell on the ground, the wind blew it towards the airplane and the airflow around the plane did the rest.
Click to expand...

Better the badge go down the intake during a power turn, than the mechanic himself; such that occurred with the CAL 737 at ELP nearly 7 years ago.
 
Indeed. I thought that happened recently, or maybe it happened again with a different carrier.(?) I saw the pictures. Nasty! :eek:
 
norcalpilot25 said:
High speed prolonged descent at idle and Np100% CL max. I believe they also got the power levers past the flight idle gate.
Click to expand...

The ability to bring the power levers beyond the flight idle gate, and the pilots actually doing it is what caused that accident. I can't speak for other turboprops, but in the Brasilia, you lose all overspeed protection once you go past that stop. Embraer updated the plane so there's a solenoid on the power levers now that won't let you go past the gate until there is weight on wheels.....but it's still not smart to try it.

In normal ops (and even irregular ops), I think you'd need an extremely compelling reason to go into reverse in the air...
 
Just wait till you find a misrigged plane. I was landing once and bought the levers back to idle only for the plane to just stop flying and slam in.

My favorite so far has been an uncommanded reverse on rollout.
 
You must log in or register to reply here.

Similar threads

barchaim
Possible to be Too Cautious/Conservative?
Replies
14
Views
869
form810
F
future pilot
Changing careers with a young family
Replies
13
Views
2K
galleycartinop
G
barchaim
40 Year Old Career Changer - Looking for Advice
2
Replies
34
Views
3K
///AMG
///AMG
Murdoughnut
Dry January Follow-Up
Replies
5
Views
960
Beaker
Beaker
Victor Squawk
Inquiry into the stuff of paper pilots
2 3
Replies
48
Views
6K
Wxfan1978
Wxfan1978
Back
Top