Jump to content
Aero Precision - Premier C130 Aftermarket Support
Aero Precision - Premier C130 Aftermarket Support
Aero Precision - Premier C130 Aftermarket Support
 
Sign in to follow this  
munirabbasi

ENG RPM

Recommended Posts

munirabbasi   
munirabbasi

Hello expertise

Before take off roll NO#2 ENG rpm drop to 84 %  for 5 second  with TIT increased ,followed by  torque decrease for 2 second.

regards

Munir abbasi

Share this post


Link to post
Share on other sites



pjvr99   
pjvr99

Sounds like a bad speed valve ..... when you change the valve,  take a good

look at the drive socket in the ADH for excessive wear

 

 

..... another culprit could be the scoop anti icing valve - they have

a tendency to pop open at high power settings when they get

older

Share this post


Link to post
Share on other sites
sharif101   
sharif101

I agree with pjvrr99.since TIT Increased it means air mass flow reduced due to bad SSV or mulfuction of anti icing sys.

Share this post


Link to post
Share on other sites
Lkuest   
Lkuest

This really needs more detail. Try to describe the malfunction in detail so we can get a mental picture of what's going on. Torque dropped for only 2 seconds. Which 2 seconds? At the beginning of the 5 seconds that RPM was low? At the end of it? If torque and RPM dropped together, it would indicate air as a likely cause. If Torque stayed high when RPM dropped, then that would indicate a propeller malfunction, and TIT happened to shoot up due to the SCV opening at 94%. If TIT shot up only after RPM dropped to 94%, that would further indicate the propeller as the cause. If TIT shot up before RPM dropped, then that would point to an air malfunction.

How did the engine recover? Did you turn off bleed air, adjust the TD switch, or did it come back on it's own? Is there a history? How many hours are on the compressor? You're also missing fuel flow, which might help indicate a fuel or TD system malfunction. You might also include much TIT and Torque moved, as well as the pressure altitude and outside air temperature. A very slight TIT increase might indicate it was fuel related because once the SCV opens, the TIT should shoot up a lot. A large TIT increase should eliminate fuel system as the cause. A SCV malfunction is usually only good for about 5000 in-lbs of torque at power and around sea level, but I'm sure the power loss could get much more severe at high altitude or hot conditions and engine wear level. There's just too many variables for us to be truly helpful with the little information that was provided.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

Champion Aerospace




×