starter engagement limitations
Guys,
I am getting confused on some issues for ATS limitations. How do you understand he following limitation? Starter engagement limitations: Start # engagement time cooling period 1 30 sec none Does that mean that if there is no N2 rotation by the time of 30 sec I need to abort?or does that mean that by 30 sec it has to reach starter cut out speed ? Is this the main reason why we start clock when starting engines? Thanks a lot. |
Don't know which type/engine you are asking but I understand it that way starter may run up to 30 sec without onward cooling.
No N2, no starter activity. |
The engine is GE CF34-3B engine for CL 604.
So then how do you know when to abort start?There must be a plain answer about engine starting/time sequence.:ugh: |
Don't know that engine. On JT8, CF 6 e.g. it's about that way
- starter engagement, start timing - N2 rise, for whatever reason the starter may run for 30 sec without cooling - if longer than 30 sec observe cooling time/number of attempts - if no N2, no starter engagemnent, no cooling time |
I believe your limitations mean that for the 1st start attempt, you can leave the starter engaged for 30 secs. max. before aborting start (for whatever valid abort start reason). After which, you can make another start attempt right away. For subsequent attempts, it doesn't specify anymore.
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I believe that starter engagement time limitations for most engines are not published primarily to limit the time the pilot uses the starter for a normal engine start, they are published to limit the time that a maintenance technician uses the starter for dry motoring, engine washes, and other non-flight related activity.
Common sense suggests that when the aircraft manufacturer publishes a starter engagement time limit, they will have ensured that the limitation allows sufficient time for a normal engine start. Thus, if pilots are running up against the starter time limits, this suggests that the there is a problem elsewhere that needs to be investigated - in other words, why is it taking longer than normal to start the engine? Just food for thought. |
Starter
CSK
Does that mean that if there is no N2 rotation by the time of 30 sec I need to abort? Engines that I am familiar with would have after start selection, 1-2 secs starter valve OPEN indication then N2 indication. Further, the time during starter selection is recorded primarily for starter motor duration limitation for the required amount of cooling before next start. Another time that is noted will be the 'fuel ON time' and if more than say 20-30secs abort the start as engine has not lit. Maybe ignitor fault, on side selection or fuel fault. After engine has run down the second start would utilise ign BOTH for the second attemp. maintenance technician uses the starter for dry motoring A typical Air Turbine Starter duration would be 3mins ops then 1min cooling 3mins ops then 1min cooling 3mins ops then 30mins cooling for example or 5mins ops then 30mins cooling possibly used during tail pipe fire or other emergency. Clearly a good normal start would be completed well before the 3mins applied. TW |
I believe that starter engagement time limitations for most engines are not published primarily to limit the time the pilot uses the starter for a normal engine start, they are published to limit the time that a maintenance technician uses the starter for dry motoring, engine washes, and other non-flight related activity. Pilots, on the other hand, did have starter limitations for normal line ops, and these were observed...to the complete bewilderment of maintenance folks.:} Clearly a good normal start would be completed well before the 3mins applied. Often times in these corcumstances, engine starts completed by lunchtime would be a major accomplishment, to the complete bemusement of many ground folks who thought we had somehow slipped back into the piston airliner mode, as we made much smoke, during engine start...and still do. Type, TriStar. |
411A
a good normal start Then starter oil changes and servicing were increased accordingly on the 211. Luckily the later 211s are a bit quicker off the mark but yes not rapid. TW |
Most modern engines require an inspection of the starter if the duty cycle has been exceeded for a length of time. Most have magnetic chip detectors on the drain plug, too check for debris.
Other checks include crash engagement at certain N2/N3; even though sometimes there isnt much left too inspect if the clutch pawls havent rengaged with the starter gearing. N2/N3/start time defo worth a check, may not be the starter u/s but the driveshaft connecting the gearbox to the engine shaft. Recent problem with a certain engine manufacturer. Oil px seen but rapid rise in N-speed indicating runaway. |
N2/N3/start time defo worth a check, may not be the starter u/s but the driveshaft connecting the gearbox to the engine shaft. Recent problem with a certain engine manufacturer. Oil px seen but rapid rise in N-speed indicating |
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