Narrative:

Start of right engine delayed until just before takeoff in accordance with fuel-saving initiatives. Start and idle operation were normal and checklists completed. On the runway; the right engine failed to accelerate from idle when throttles were advanced. This is not an uncommon occurrence with the JT8D; so I just continued to advance the throttles slowly waiting for a response. After 10 seconds; the left engine was spooled and the right was still at idle. I pointed it out to the captain and recommended he abort the takeoff. However; since we had not used any appreciable runway yet; he elected to continue. After about 15 seconds; the right engine slowly started to spool up. I advanced the throttles the rest of the way; and the takeoff was continued normally. The captain made a logbook entry at the completion of the flight regarding the slow acceleration. I believe bleed valves may have been stuck open on the right engine after start. Combined with the load of the right pack; this inhibited spool-up for takeoff. Delaying the second engine start until just before takeoff tends to rush completion of crew duties; exacerbating the problem. This issue is common on the JT8D and not easy to detect. Pratt & whitney states that the engines should spool to 14 EPR within 3 seconds of each other. I think the takeoff should have been aborted and static check of spool-up initiated prior to a second takeoff; but we have no procedure for this; and it was not my decision to make. I suggest that the operations manual be revised to include information regarding engine spool-up time on takeoff; and procedures to be followed when it is abnormal. I also think we should have a requirement for the first officer to advance the throttle to 65% N2 following every start to ensure bleed valves are closed. This is a common problem; and can also cause post-start over-temperatures.

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Original NASA ASRS Text

Title: MD80 FO REPORTS VERY SLOW ENGINE ACCELERATION DURING TKOF AND BELIEVES BLEED VALVE MAY HAVE BEEN STUCK OPEN.

Narrative: START OF R ENG DELAYED UNTIL JUST BEFORE TKOF IN ACCORDANCE WITH FUEL-SAVING INITIATIVES. START AND IDLE OP WERE NORMAL AND CHKLISTS COMPLETED. ON THE RWY; THE R ENG FAILED TO ACCELERATE FROM IDLE WHEN THROTTLES WERE ADVANCED. THIS IS NOT AN UNCOMMON OCCURRENCE WITH THE JT8D; SO I JUST CONTINUED TO ADVANCE THE THROTTLES SLOWLY WAITING FOR A RESPONSE. AFTER 10 SECONDS; THE L ENG WAS SPOOLED AND THE R WAS STILL AT IDLE. I POINTED IT OUT TO THE CAPT AND RECOMMENDED HE ABORT THE TKOF. HOWEVER; SINCE WE HAD NOT USED ANY APPRECIABLE RWY YET; HE ELECTED TO CONTINUE. AFTER ABOUT 15 SECONDS; THE R ENG SLOWLY STARTED TO SPOOL UP. I ADVANCED THE THROTTLES THE REST OF THE WAY; AND THE TKOF WAS CONTINUED NORMALLY. THE CAPT MADE A LOGBOOK ENTRY AT THE COMPLETION OF THE FLT REGARDING THE SLOW ACCELERATION. I BELIEVE BLEED VALVES MAY HAVE BEEN STUCK OPEN ON THE R ENG AFTER START. COMBINED WITH THE LOAD OF THE R PACK; THIS INHIBITED SPOOL-UP FOR TKOF. DELAYING THE SECOND ENG START UNTIL JUST BEFORE TKOF TENDS TO RUSH COMPLETION OF CREW DUTIES; EXACERBATING THE PROB. THIS ISSUE IS COMMON ON THE JT8D AND NOT EASY TO DETECT. PRATT & WHITNEY STATES THAT THE ENGS SHOULD SPOOL TO 14 EPR WITHIN 3 SECONDS OF EACH OTHER. I THINK THE TKOF SHOULD HAVE BEEN ABORTED AND STATIC CHK OF SPOOL-UP INITIATED PRIOR TO A SECOND TKOF; BUT WE HAVE NO PROC FOR THIS; AND IT WAS NOT MY DECISION TO MAKE. I SUGGEST THAT THE OPS MANUAL BE REVISED TO INCLUDE INFO REGARDING ENG SPOOL-UP TIME ON TKOF; AND PROCS TO BE FOLLOWED WHEN IT IS ABNORMAL. I ALSO THINK WE SHOULD HAVE A REQUIREMENT FOR THE FO TO ADVANCE THE THROTTLE TO 65% N2 FOLLOWING EVERY START TO ENSURE BLEED VALVES ARE CLOSED. THIS IS A COMMON PROB; AND CAN ALSO CAUSE POST-START OVER-TEMPS.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.