Using MTOP
Hello, when starting on a short airfield, I would like to make use of MTOP. But this is only possible if I move the Power levers within 6 Seconds, otherwise it goes automatically back to NTOP.
Can someone from the real world explain me the reason why it must come back to NTOP so quick?
Thanks and regards, Guenther
Comments
I am not a real-world pilot, but I found the following ...
See this document here: smartcockpit.com/docs/Q400-Power_Plant.pdf
Page 10 says, "When the MTOP discrete is activated by the pilot, the Maximum Take-off (MTOP) Rating is selected by the FADEC anytime the condition lever is in the 1020 RPM position".
Therefore, I would suggest it it goes automatically back to NTOP because the condition lever isn't in the 1020 RPM position.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.avsim.com/forums/topic/553058-mtop/&ved=2ahUKEwjHjqjLuKboAhWNGuwKHaqaBIoQFjAIegQIBRAB&usg=AOvVaw2FqBzZMH5iRbFU1PcI3RXN
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.avsim.com/forums/topic/553058-mtop/&ved=2ahUKEwjHjqjLuKboAhWNGuwKHaqaBIoQFjAIegQIBRAB&usg=AOvVaw2FqBzZMH5iRbFU1PcI3RXN
The link was on the way, where I had no opportunity to read the somewhat more extensive documents at home. The TAKEOFF WITH MAXIMUM TAKEOFF POWER is in itself intended, but probably not a normal procedure. MTOP is automatically active at takeoff when the uptrim becomes active. It is also requested by the PF for a Single Engine Go Arround and activated by pressing MTOP. The use cases for the takeoff with MTOP are unfortunately poorly described, but it does not seem to work for the Dash as described in other documents. It works in that you can activate MTOP after setting the starting power and thus reach 100%.
When this would be used for the takeoff remains open, even if, as can be read in my link, it is only used in an emergency.
Well Folks, its a bit strange for me that TOP should only be for emergency cases or Go around. I use it if I depart from a short Airfield. I found in meantime 2 possibilities to activate MTOP:
a) I push MTOP button and move PL forward immediately, thats possible within 6 sec.
b) I start with NTOP and when full Power is applied, then I hit the MTOP button and I get also maximum power for Takeoff.
Guenther
Hello Günther,
I would prefer b) for a simple reason if you use a) and for a reason or another you won't push the PL immediately you are not going to get what you are looking for and that could lead to some problem. When you have the PL max forward you are committed to TOFF unless pb before V1.
I do not know if it is something similar like the water and methane which was used quite some years ago and as I remember on F27 and FH227 but could not be used more than one minute.
You would not use MTOP only in case of emergency but as you correctly stated on short runways and also excessive temperature and high altitude (could be a combination of the three factors like PARO - VQPR).
Regards,
JP
I looked for something again, but unfortunately also found the Dash8 300 comparable that the MTOP is only used in abnormal situations and in an emergency, as the quoted text shows.
Also referred to as Maximum Takeoff Power (MTOP). This power setting is referenced in the performance section of the QRH and is used for abnormal and emergency situations described in this manual.
Corresponding examples are unfortunately only available in the QRH for the cases Engine Failure (and Uptrim) or Go Arround with single engine, but are not described in detail, since the information must be requested separately from the manufacturer. I think for a takeoff the MTOP is not used as a normal calculation size. If, as in Günter's example, a short Rwy is to be started, one has to check on the basis of the performance data whether this is logical and permitted at all.
The MTOP is used as the "last reserve" or turbo for starts of too short Rwy, I would currently exclude with the knowledge of what I could read. Here NTOP represents the normal (maximum) starting power, which RED TOP TRQ can reduce according to the calculated takeoff performance
MTOP (Maximum Take Off Power) is used mainly when it is needed in order for the aircraft to take off from a shorter runway when other configurations of take-off power (NTOP (Normal Take Off Power), RDC TOP (Reduced Take Off Power)) and flap settings (5, 10, 15) are not enough. This all depends on temperature, elevation, runway length, and aircraft weight. Real world we have ACARS, dispatched numbers, or charts we can use to tell us what to use.
MTOP will also automatically activate (if I remember correctly) in the event of an engine failure when the power levers are in the rating detent and NTOP is selected for take off. It will also activate automatically during and engine failure during a go-around (Once again I believe the power levers have to be in the rating detent). This is called "Uptrim".
In my ~2.5 years of flying the Q400 IRL I don't think I've ever needed to use it, however I see it plenty in the sim when we're doing engine failures and such.
Edit: Just read your question properly. It shouldn't come back down to NTOP. It should stay in MTOP unless its deselected or the condition levers are brought down to 900 or 850. Freddy is correct that the condition levers have to be in the 1020 position. When it is selected we do it as part of the "after start checks", which are done after the condition levers are brought out of start feather and into the 1020 position for take off.