Jump to content

ENG RPM


munirabbasi
 Share

Recommended Posts

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

Link to comment
Share on other sites

  • 2 months later...

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.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...