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convair880mfan
Topic Author
Posts: 163
Joined: Fri Jun 25, 2021 12:33 am

Reducing to climb power during a turn

Sun Jul 18, 2021 6:03 pm

Can a jetliner go from takeoff thrust to climb power during a turn without reducing bank angle?

I know there are sometimes limitations on bank angle on aircraft after takeoff. I have seen charts where for various jetliners it is stated that pilots should keep bank angle below X number after take off with flaps still lowered and there are charts on proper bank angle for close in turns immediately after takeoff at takeoff thrust.

But what if an immediate turn is required after takeoff to avoid terrain? A steep bank is initiated but during the turn climb power is selected. Does the bank angle need to be reduced for safety reasons? Sorry if this is a lame question.

I live in Albuquerque New Mexico and when taking off to the east planes seem to turn after about 20 second to avoid flying over the Manzano Mountains [or for some other reason]. If I recall correctly, the aircraft are still at takeoff thrust when the turn is initiated. The bank angle seems [?] steep and the flaps are yet to be retracted. I can't recall if the bank angle is reduced when climb power is selected or whether it is maintained.

Planes I have flown in this situation are the Boeing 707, 727, 737, 757 ... the DC-9 and the MD-80. Is the procedure the same for all types and what about Airbus aircraft? Thanks to one and all who respond.
 
GalaxyFlyer
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Re: Reducing to climb power during a turn

Sun Jul 18, 2021 7:13 pm

Yes, of course, thrust can be adjusted in any situation, if necessary. OEI departures are normally planned at maximum power and bank restricted to 15 degrees until clean and accelerating but that’s an emergency with loss of engine.
 
113312
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Joined: Sat Apr 16, 2005 9:09 am

Re: Reducing to climb power during a turn

Mon Jul 19, 2021 8:38 pm

Bank angle limitation is a function of airspeed and stall margin.
 
e38
Posts: 879
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Re: Reducing to climb power during a turn

Tue Jul 20, 2021 2:46 am

convair880mfan wrote:
Can a jetliner go from takeoff thrust to climb power during a turn without reducing bank angle?

But what if an immediate turn is required after takeoff to avoid terrain? A steep bank is initiated but during the turn climb power is selected. Does the bank angle need to be reduced for safety reasons?

If I recall correctly, the aircraft are still at takeoff thrust when the turn is initiated. The bank angle seems [?] steep and the flaps are yet to be retracted. I can't recall if the bank angle is reduced when climb power is selected or whether it is maintained.


convair880mfan, so many questions . . . let's see.

First question, "can a jetliner go from takeoff thrust to climb power during a turn without reducing bank angle?"

Like GalaxyFlyer (Reply # 2) stated above, Yes.

With regard to your statement, "A steep bank is initiated but during the turn climb power is selected. Does the bank angle need to be reduced for safety reasons?"

A transport category aircraft in Part 121 (airline) operations is not going to be making a steep bank (greater than 45 degrees) turn. With all engines operating, turns are predicated on "standard rate" turns--approximately 30 degrees--and that takes into account operating at climb power. So, in the example you cited bank angle does not need to be reduced.

Concerning your statement, "aircraft are still at takeoff thrust when the turn is initiated." In many aircraft, depending on where you are seated, and on operating conditions (gross weight, temperature, altitude, etc.) it is occasionally difficult to determine when thrust has been reduced from takeoff thrust to climb thrust, so it may not be valid for you to say that aircraft are still at takeoff thrust when the turn is initiated. Thrust is generally reduced from takeoff thrust to climb thrust at either 1000 or 1500 feet AFE in the U.S.

In transport category aircraft, takeoff data and climb performance are predicated on the loss of an engine, with the requirement to maintain adequate obstacle clearance on the departure procedure. This will probably require the use of Maximum Continuous Thrust throughout the departure procedure and the use of half standard rate turns if required. However, if all engines are operating, there will be increased performance, and therefore, it would be normal to reduce thrust from takeoff thrust to climb thrust at the normal point, 1000/1500 feet AFE and to make standard rate turns--not steep turns--at the appropriate points.

Now Albuquerque, with mountains to the east of the field--presents special challenges. Each air carrier may develop their own (FAA approved) departure profile to expedite their aircraft climbing to a safe altitude as quickly as possible. Such profiles may include climbing at Vx airspeed, rather than Vy, with flaps at the takeoff setting until reaching a certain altitude, or perhaps climbing at Vzf, rather than accelerating to 250 KIAS, until a certain point on the departure.

It looks like the eastbound departure procedures at Albuquerque (MNZNO and GRZZZ departures) departing Runway 8 require turns to the north or south--to avoid the mountains--until such time as the aircraft are high enough to clear the terrain and safely turn to the east. They eastbound SIDs also have restrictions of a maximum airspeed of 220 KIAS until above a specified altitude (close to Vzf for many aircraft depending on gross weight). This is designed to allow aircraft to climb higher more quickly (with respect to distance traveled) and also maintains a suitable ground track using standard bank turns so aircraft maintain a safe distance from the terrain. As you may have experienced, aircraft departing Albuquerque for points east, DFW/DAL for example, will turn either north or south until obstacle clearance is assured (above 11,500 feet MSL at MNZNO; above 12,100 feet MSL at GRZZZ) before turning back to the east.

In the event of engine loss, it would not be prudent to attempt to cross the mountains. Rather, a pilot would fly the departure procedure, using appropriate engine out procedures, and maneuver back to the west before returning to land at ABQ or proceeding to an alternate airport.

Airbus narrow body aircraft (A319/A320/A321) procedures are the same.

I hope I was able to address some of your questions and interests.

e38
 
convair880mfan
Topic Author
Posts: 163
Joined: Fri Jun 25, 2021 12:33 am

Re: Reducing to climb power during a turn

Tue Jul 20, 2021 5:11 pm

Thank you so much e38 for the trouble you took to provide such a really detailed and helpful answer. Thanks to all the other respondents too.
 
T54A
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Re: Reducing to climb power during a turn

Wed Jul 21, 2021 4:01 pm

Although the above answers are correct, I would add the following. I have operated A340's out of JNB (5500ft AMSL) for nearly 15 years, and my company applied a max Flex Temp take off thrust and max Derate climb policy. In a heavy A340, I would be reluctant to reduce thrust from Flex take off to Derate (1 or 2) during a initial turn after take off. You would be asking for a POSSIBLE Alpha Floor event in this case. I would either wait until after the turn to reduce to Derate Climb or I would select normal climb and then insert Derate after the turn. This not procedure but rather airmanship.
 
CosmicCruiser
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Re: Reducing to climb power during a turn

Thu Jul 22, 2021 11:36 pm

you can always just lower the nose as you reduce power
 
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Starlionblue
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Joined: Fri Feb 27, 2004 9:54 pm

Re: Reducing to climb power during a turn

Fri Jul 23, 2021 1:27 am

CosmicCruiser wrote:
you can always just lower the nose as you reduce power


That's what the FD tends to tell you to do anyway. ;)
 
CosmicCruiser
Posts: 2518
Joined: Tue Feb 22, 2005 3:01 am

Re: Reducing to climb power during a turn

Sat Jul 24, 2021 12:12 am

Yep
 
GalaxyFlyer
Posts: 8078
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Re: Reducing to climb power during a turn

Sat Jul 24, 2021 1:56 am

Starlionblue wrote:
CosmicCruiser wrote:
you can always just lower the nose as you reduce power


That's what the FD tends to tell you to do anyway. ;)


I certainly hope a competent pilot wouldn’t need a FD to know that!
 
AABusDrvr
Posts: 178
Joined: Sat Dec 03, 2016 6:48 am

Re: Reducing to climb power during a turn

Sat Jul 24, 2021 2:31 am

On the 737NG, occasionally climb thrust is a higher power setting than takeoff thrust. So when climb is commanded, the power increases from the takeoff setting.
 
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Starlionblue
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Re: Reducing to climb power during a turn

Sat Jul 24, 2021 2:56 am

GalaxyFlyer wrote:
Starlionblue wrote:
CosmicCruiser wrote:
you can always just lower the nose as you reduce power


That's what the FD tends to tell you to do anyway. ;)


I certainly hope a competent pilot wouldn’t need a FD to know that!


:rotfl: :rotfl: :rotfl:

"Hmmm. I wonder why the speed is decaying so fast..."
 
CosmicCruiser
Posts: 2518
Joined: Tue Feb 22, 2005 3:01 am

Re: Reducing to climb power during a turn

Sat Jul 24, 2021 11:39 am

We used to do a noise abatement departure out of Long Beach, I believe, in the 727 that was pretty aggressive. I don't remember the details but at around 1500' you made a big power reduction and a left turn. You really had to push the nose over to keep the speed. In a way it was fun but you had to pay attention.

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