Engine Bog Down
Joined: Dec 2004
Posts: 30
Likes: 0
From: Jeddah, Saudi Arabia
Common on RR Allison T56/501. During starting engine will not accelerate to low speed ground idle (72%) after starter button release, or will not accelerate to normal ground idle. Has a tendency to surge/stall once started. Normally caused by dirty fuel nozzles, dirty compressor and/or turbine, or fuel control unit has shifted to lean.
Joined: Jul 2007
Posts: 2
Likes: 0
From: Humpty Doo
What pjvr99 has described is a stalled or stagnated start , Bog Down , occurs most often in the T56 when pwr demanded is greater than power available , such a selecteing reverse at high speeds with a high OAT , the RPM will decay outside normal limits and the engine will wind down , if the power lever is advanced to reduce blade angle RPM should recover .I have a LM brochure produced for a C130 operators conference and they use the term "Unscheduled rundown" to describe "bog down".
Joined: Dec 2004
Posts: 30
Likes: 0
From: Jeddah, Saudi Arabia
13 Mile Arc - What pjvr99 has described is a stalled or stagnated start , Bog Down , occurs most often in the T56 when pwr demanded is greater than power available , such a selecteing reverse at high speeds with a high OAT , the RPM will decay outside normal limits and the engine will wind down , if the power lever is advanced to reduce blade angle RPM should recover .I have a LM brochure produced for a C130 operators conference and they use the term "Unscheduled rundown" to describe "bog down".
13MA is correct (sorry, early morning). Sometimes it's difficult to determine whether bogdown, stagnation or flameout occurred, depending on the crew reports. However, the same checklist is used to verify/rectify these 3 conditions.
13MA is correct (sorry, early morning). Sometimes it's difficult to determine whether bogdown, stagnation or flameout occurred, depending on the crew reports. However, the same checklist is used to verify/rectify these 3 conditions.





