Pilot Question: Full Power - How Long?

[Studley]

Okay, I thought this was highly unusual during my flight from EWR-DFW yesterday, so out of curiousity, I thought I would ask the pilots here about it.

After takeoff in our MD-80, we reached our cruising altitude of 31,000 feet, but instead of throttling back, as is normally the case, the turbofans remained at full power for the entire flight, until it was time to descend. Just as a note, as a result, we touched down 25 minutes early, and sat outside the gate area (lovingly known as the "penalty box") until ten minutes past our original arrival time, which was cool with me.

My question: The air was moderately choppy at times, but nothing really out of the ordinary for this corridor (which I have flown numerous times). Was this was done to maintain lift and stability, meaning things were a bit more serious than normal? Have you pilots ever had to do this in your aircraft?

[EXASaab]

Full Power?! Well I could write a whole post on what is full power... With the CRJ Full Power is never applied for take-off. We plug in temperatures and weights for that particular airport and runway specific and the computer spits out a Take-Off power setting. We call it "Full Power" if we do not Reduce Thrust which is only to save the company money by reducing the temps on the engines (i.e running cooler) Which increases the life of the engines.

As you are climbing to altitude the engines "lose" power since the air density is less, as we continue to climb we have to keep "pushing up the power" to maintain that Climb N1 setting (N1=Fan Speed). If we are really heavy (max gross T/O weight) and it's a warm summer day then the CRZ N1 setting may not be but a percent or 2 less than climb was also while you are climbing to the higher altitudes you have to reduce your vertical speed(climb rate) to keep from decreasing your forward airspeed. For example in the CRJ this morning we we had 50 Pax 1200lbs +/- Cargo climbing to FL310 (31,000 feet). About FL260 and up we had gone from 290kts & 1500 feet per minute down to 250kts and 500 feet per minute. We were flight planned for .74 Mach which for the CRJ is usually around 290-300 Knots incated depending on altitude and temperture.
So to accelerate to .74M after being at 250kts we just leave the power where it is... or reduce it to the CRZ setting which is usually not much different from CLB at the higher altitudes therefore you wouldn't really here much of a change in the sound... At the lower altitudes where the air is thicker the engines are sucking,squeezing,banging, and blowing more air so you here more of a power reduction...

Hope this makes sense and I have not confused you?!
I am writing this at 1:30 A.M. after a 4 day trip.
If there is any spellin', grammar, or sentences that don't make any sense... now you know why.
:grin:

If you have more questions... ask and I'll try to answer.

[bridget74]

As you are climbing to altitude the engines "lose" power since the air density is less, as we continue to climb we have to keep "pushing up the power" to maintain that Climb N1 setting (N1=Fan Speed). If we are really heavy (max gross T/O weight) and it's a warm summer day then the CRZ N1 setting may not be but a percent or 2 less than climb was also while you are climbing to the higher altitudes you have to reduce your vertical speed(climb rate) to keep from decreasing your forward airspeed. For example in the CRJ this morning we we had 50 Pax 1200lbs +/- Cargo climbing to FL310 (31,000 feet). About FL260 and up we had gone from 290kts & 1500 feet per minute down to 250kts and 500 feet per minute. We were flight planned for .74 Mach which for the CRJ is usually around 290-300 Knots incated depending on altitude and temperture.
So to accelerate to .74M after being at 250kts we just leave the power where it is... or reduce it to the CRZ setting which is usually not much different from CLB at the higher altitudes therefore you wouldn't really here much of a change in the sound... At the lower altitudes where the air is thicker the engines are sucking,squeezing,banging, and blowing more air so you here more of a power reduction...


And here I was just thinking that maybe he had a pilot with a need for speed. :grin:

[EXASaab]

And here I was just thinking that maybe he had a pilot with a need for speed.



Just the other day I had a female controller ask me how fast I was going... "Flagship 5900 say speed" 330 Knots, I say... she keys up the mic and says...."woooooooooooow, oook".. I think she was impressed! :grin:
:grin:

[bridget74]

Chicks dig the fast planes. :grin: :grin: :wink_2:

[IntMaverick]

Chicks dig the fast planes. :grin: :grin: :wink_2:

<font color="purple">Hey Saab do you have room in the seat across the centre console from you? Can I be your apprentice? :cool_2:

[EXASaab]

Chicks dig the fast planes



That's one thing about the CRJ200...We are Smoookin'..not only in cruise but also during landing.... ever sit and watch a CRJ approach? Ever noticed how it looks like we are aimed at the dirt :shocked:then at the last minute we yank it up and greaser' right on.... :grin:

Had a Bus Capt on the jumpseat last month who was really shocked at our landing speed...we were doing something like 155kts at a mid-weight.... upper 30,000- low 40,000 lbs.... he said that speed would be very close to the speed the 319/320 would be at MAX Landing... which is a heck'uva lot more than the 47,000lbs Max Landing on the "barbie fun jet". :cool_2:


EXA whispers to bridget... "hey baby wanna take a ride in my barbie jet" :pilot_2:

[Paddles_up]

Chicks dig the fast planes.



Hey buddy...you ain't done "speed" until you done a CRJ-700. Come on over and I'll take ya for a "trip around the patch"! :plane: :windsock:

[Angelflyer]

Hell ya!!! i have a co-worker who gave me a 20 minute convo on her recent trip on the crj from pdx down to psp. she said it was fun. she got shot straight up and fast and the decent into psp as we all know is bumpy. she loved her horizon flight. i tried explaining how the crj is the wave of the future...LOL :wink_2:

[corp_fa]

Speed is not always the best! Just did a trip at mach .89 on a Gloabal Express - due to customers request (normally we chug along at .85).
As I am working in the back time goes by even faster when they want a whole meal service in 50mins. Once you hit above .85 it gets pretty lound in the cabin - sounds like a waterfall. Great otherwise.

[EXASaab]

The CRJ gets pretty noisey above 310 knots(wind noise).... The company flight plans us at .74 mach not to exceed 300 konts for fuel conservation... although we regularly fly at MMO around 335 knots .85 Mach, when ATC request best forward speed. :cool_2: :grin:

[pilotohalcon]

In the DC8 and 9 (antiquated by today’s standards I know so no laughing) we have various power settings. First in the “8” the FE and FO will compute “Takeoff power”. This is determined by runway length, runway condition, (Wet, snow, slush etc) obstacles in the takeoff path, and density altitude. Then if the situation warrants it, for noise abatement we will figure out a reduced power take off. In the 8 or the 9 the PF (Pilot flying) when cleared for Take off will advanced power to 1.3 EPR to stabilize the engines then advance the throttles to either the T/O or reduced power setting then command “set T/O power” or “Set reduced power” then the PNF will fine tune the power to the pre agreed amount while making sure the other limitations will not be exceeded. IE TGT, N1, EPR etc. after rotation and into the climb profile the PF will command for the 8 “set climb power” and the FE (flight engineer) will reach up to reduce power even more to a power that is within the continuous limits of that engine. In the 9 the command after T/O would be “set 1.7 (EPR setting for noise abatement) slats retract” and at 3000 feet AGL the next command would be from the PF “set climb power” so power would be increased again to a pre arraigned power setting again not to exceed engine limitations. There is a power setting called “Maximum thrust” but that is only used for the direst situations. Wind shear is a prime example. During operation in that realm the engines are exceeding one or more of their limitations (probably more then one) and the utmost care is required in reducing the power when the emergency is over to a more realistic level.
Both A/C will require continuous monitoring and tweaking of the power through out the climb. BUT one thing we have over some of the newer A/C is pure speed. Especially in the “8” The MMO is .88 which we routinely see .82 or up to .86 if we are in a hurry. The “9” has a MMO of .84 and we will use .79 or so most of the time. Descents are normal carried out at idle thrust. We have not touched on the various profiles to include flap/slat operation but that is another class entirely

[pilotohalcon]

You know something, after reading my reply I realized I said everything I wanted to say EXCEPT to answer your question. :shocked: OK 2 minutes at T/O power for us.
j

[traveler]

:grin:

5 here.
or 10 in an emergency.
Or when you really need it .. well, as long and as much as you can squeeze out of it. you get the point.

[pilotohalcon]

The 2 min is just ABX limit, the engine manufacturer say 5 also. And "Radar" power is all you can squeeze out if it as long as you need it since you are already toast anyway.
:pilot_2: j

[Lame.]

That is unusual, as people have said, you are normally limited to 5 or 10 minutes max, unless an emergency.

I had the same thing on an MD80 one day, but it was my fault. :wink_2:

I was flying with the aircraft taking vibration readings of the engines, and I had the Captain leave the engines at high power so I could take the readings, we arrived in Cairns way too early. :grin:

Another time we were ferrying a Fokker F27 from Australia to England, and as we departed Athens the controller would not clear us for takeoff unless we guaranteed to be at a certain altitude by a certain time (I cannot remember the exact figures now).

So the Captain said of course we can, as we were in a hurry to get to Milan. :wink_2:

Well we DID it but only by leaving both Darts at takeoff power for the whole climb. :crazy:

When we levelled out we found out why, within a minute we had a Kingair pass directly under us and a B737 pass directly over us.

Some of the busiest airspace I have ever seen.