MD-80 Series (DC-9-80) Undifferentiated or Other Model
Situational Awareness
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem
Aircraft
On the takeoff roll in ZZZ with standard power set it seemed to me that the takeoff roll was a little longer than it should be. There was plenty of runway left and checking engine parameters I noticed the EPR readout on the EPR limit display was not steady and lower than it should be. I immediately pushed up the throttles to correct setting. Considering airspeed; runway remaining and aircraft performance it was safe to continue and safer than rejecting the takeoff. Immediately after takeoff the R Engine Heat Valve amber light on the overhead panel began to cycle off and on very rapidly along with the EPR readout. After assuring the power was set properly I turned on the R Engine heat and all indications showed normal for Engine heat on. I then turned R Engine heat off and all indications were normal for the rest of the flight. All of us know that on the airplanes the Engine heat valve slowly cycling on and off in cruise is almost a normal occurrence and is usually self-correcting before anything can be done; or performing the QRH procedure of cycling the switch has always corrected the problem. This is the first time in my experience it has happened other than cruise; and in my view on takeoff roll can be a very serious situation. I would hope that maintenance can solve this uncommanded engine heat valve problem.
A crew member in an MD-80 reported that takeoff roll seemed a little longer when he discovered #2 engine EPR was low.