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convair880mfan
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How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 4:27 am

Is it 400ft.agl? Or can an airliner start turning right after the gear is retracted?

Back in the day in Albuquerque I could count to 60 before watching a 707 or 880 begin a turn. Later as a passenger on Southwest Airlines' 737-200s I could usually count to 20 before the aircraft turned. In both of these cases, the jetliners were headed easterly toward steeply rising terrain.

Is there some protocol for turns or rules of thumb? I can't imagine a plane turning before gear up and never experienced it as a passenger.
 
Snuffaluffagus
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 4:37 am

Here at my airline, we can do immediate turns at 50 feet on the 737. Needed for Juneau on a special downwind departure we are authorized for. Otherwise it's 400 ft for your run of the mill departure, unless specified.
 
convair880mfan
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:02 am

Wow. 50. Thanks for your response.
 
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Starlionblue
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:25 am

Our ops manual says 400feet AAL, or as specified in the port notes. Same policy as Snuffaluffagus, in other words.
 
convair880mfan
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:39 am

I wonder how the 400 figure was arrived at? How long is an aircraft in ground effect after takeoff? I wouldn't imagine its very long at those speeds. At 500 agl do you do a 30 degree turn or 15 %.
 
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Aaron747
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:49 am

See a lot of this in the Hawaiian islands due to terrain and strict noise abatement. Departing from HNL runways 8L/R, it has always been typical to start the departure turn as soon as gear are up.

https://youtu.be/tVYtZ4zXLUI?t=408

https://youtu.be/nsu9P3oEHLw?t=1088

https://youtu.be/jXMfT1RMzR8?t=72

https://youtu.be/RTUHguGfQUg?t=65

Departing KOA runway 17:

https://youtu.be/ZZvju1qfDkA?t=202

Departing LIH interisland on runway 3:

https://youtu.be/HIZyhfDT238?t=482

Departing OGG interisland on runway 2:

https://youtu.be/dNSny_5Q96A?t=139

Departing ITO interisland on runway 26:

https://youtu.be/qNRSnm5Zjs4?t=9
 
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Starlionblue
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 9:46 am

convair880mfan wrote:
I wonder how the 400 figure was arrived at? How long is an aircraft in ground effect after takeoff? I wouldn't imagine its very long at those speeds. At 500 agl do you do a 30 degree turn or 15 %.


On Airbus, takeoff inhibit for warnings stops at 400 feet. But I don't know if that is coincidental or related.
 
DH106
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 10:32 am

Concorde had to do an early left turn departing JFK on 31L didn't it? Canarsie something departure.
From about 0:50 in this vid
https://www.youtube.com/watch?v=xgOo6sqJQmA
 
vikkyvik
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 2:02 pm

So just out of curiosity, taking BOS as an example, takeoffs from 22L/R perform an essentially immediate turn to 140. Here is the language I found in the Logan Two departure procedure on Airnav:

TAKEOFF RWYS 22L/22R: Climbing left turn heading 140

So does that mean an immediate turn, or is it assumed aircraft will wait until they hit 400 feet to commence the turn?

Thanks.
 
N353SK
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 3:02 pm

vikkyvik wrote:
So just out of curiosity, taking BOS as an example, takeoffs from 22L/R perform an essentially immediate turn to 140. Here is the language I found in the Logan Two departure procedure on Airnav:

TAKEOFF RWYS 22L/22R: Climbing left turn heading 140

So does that mean an immediate turn, or is it assumed aircraft will wait until they hit 400 feet to commence the turn?

Thanks.


At my carrier we would interpret that to turn at standard height (400' in VMC).

Compare this to the National 7 Departure out of DCA where, upon departing runway 1, the SID instructs a left turn as soon as practical. This is a departure where we'd start the turn as soon as we're airborne.
 
adipasqu
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 4:36 pm

BUR has a very quick climbing turn right after departure off of RWY 15:

https://aeronav.faa.gov/d-tpp/2109/0006 ... ddest=(BUR)

To me, it always seems that the turn starts very quickly after the wheels are off the ground, possibly (way) less than 400' AAL.
 
GalaxyFlyer
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:17 pm

DOC 8168 specifies the Initial Climb Area (ICA formerly Zone 1) to be 400’, actually a metric height very close. It the initial obstacle clearance plane. Once at 400’, the the OIS looks until reaching a enroute altitude. Minimum gradient is 152’/nm plus a 48’/nm buffer, hence the minimum climb out of 200’/nm unless obstacles penetrate the 200’/nm plane. Obstacles inside the 400’ / 2 nm point are close-on and climb gradients cannot be increased there, obstacles can only be identified and then used in a runway analysis.

One way to deal with close on obstacles is a “turn as soon as practical”, but that will impose a visibility minimum-1 nm I believe.
 
N1120A
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:42 pm

400' AAL at the end of the runway is advisory, based on TERPS criteria. Given that, most 121 and 135 operators make it standard procedure and pretty much everyone else does it because they learn that way. At some airports, earlier turns may be advisable, such as when departing the North Field at OAK where the departure path with 30 may converge and many folks make the right turn early off 28R. Similarly, there's what was mentioned about JNU earlier.

adipasqu wrote:
BUR has a very quick climbing turn right after departure off of RWY 15:

https://aeronav.faa.gov/d-tpp/2109/0006 ... ddest=(BUR)

To me, it always seems that the turn starts very quickly after the wheels are off the ground, possibly (way) less than 400' AAL.


All turbine departures off 15 at BUR turn right to 210 at the standard 400' AAL/end of the runway. The lone exception might be if they give them the ELMOO9 going southeast, which we use in light airplanes headed in that direction to pick up V186. It isn't a quick turn, just a regular one. It just happens to be 60 degrees, so you notice the fact that you're turning.
 
adipasqu
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 5:54 pm

N1120A wrote:
All turbine departures off 15 at BUR turn right to 210 at the standard 400' AAL/end of the runway. The lone exception might be if they give them the ELMOO9 going southeast, which we use in light airplanes headed in that direction to pick up V186. It isn't a quick turn, just a regular one. It just happens to be 60 degrees, so you notice the fact that you're turning.


Okay, maybe they are climbing so fast to 400' AAL that it seems like a quick turn, when it is not. A minimum climb of 340' per NM to 2100 on RWY 15 for OROSZ 2 and SLAPP 2 means that turn is starting no later than just over 1 NM from the end of the pavement. That's not very far.
 
N1120A
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 6:15 pm

adipasqu wrote:
N1120A wrote:
All turbine departures off 15 at BUR turn right to 210 at the standard 400' AAL/end of the runway. The lone exception might be if they give them the ELMOO9 going southeast, which we use in light airplanes headed in that direction to pick up V186. It isn't a quick turn, just a regular one. It just happens to be 60 degrees, so you notice the fact that you're turning.


Okay, maybe they are climbing so fast to 400' AAL that it seems like a quick turn, when it is not. A minimum climb of 340' per NM to 2100 on RWY 15 for OROSZ 2 and SLAPP 2 means that turn is starting no later than just over 1 NM from the end of the pavement. That's not very far.


Both SIDs publish the turn at the end of the runway. It isn't hard to get to 400' AAL from a 800-900' elevation airport from a 6900' runway for the airplanes that operate at BUR.
 
N353SK
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 8:42 pm

N1120A wrote:
adipasqu wrote:
N1120A wrote:
All turbine departures off 15 at BUR turn right to 210 at the standard 400' AAL/end of the runway. The lone exception might be if they give them the ELMOO9 going southeast, which we use in light airplanes headed in that direction to pick up V186. It isn't a quick turn, just a regular one. It just happens to be 60 degrees, so you notice the fact that you're turning.


Okay, maybe they are climbing so fast to 400' AAL that it seems like a quick turn, when it is not. A minimum climb of 340' per NM to 2100 on RWY 15 for OROSZ 2 and SLAPP 2 means that turn is starting no later than just over 1 NM from the end of the pavement. That's not very far.


Both SIDs publish the turn at the end of the runway. It isn't hard to get to 400' AAL from a 800-900' elevation airport from a 6900' runway for the airplanes that operate at BUR.


Both of those SIDs predicate their obstacle clearance on the assumption that the pilot will begin the turn at 400' AGL and comply with the charted climb gradients (on the SLAPP 2 from Runway 15, 340 feet per nautical mile to 2100). If turning at 400' AGL is not adequate for obstacle clearance, the SID will specify an altitude or fix at which the turn will commence. If an immediate turn is required the SID will include the phrase "turn left (right) as soon as practicable." For further details see AIM 5-2-9 paragraph e.1.
 
thepinkmachine
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 9:05 pm

EASA rules specify minimum turn height of 50' or half of the wingspan, whichever is greater (with bank angle limited to 15 deg until 400'). Hoever normal ops is 400'
 
GalaxyFlyer
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Re: How soon after takeoff can an airliner safely start a turn?

Fri Oct 01, 2021 9:16 pm

Here’s TERPS definition of ICA, which establishes the 400’ AAE turn procedure.

13-1-5. Ceiling and Visibility. A ceiling and visibility may be specified to see and avoid penetrating obstacles within the ICA (extended) 3 SM or less from the DER.
a. Ceiling. Specify a ceiling value equal to or higher than the height of the obstruction above the airport elevation. Ceilings must be specified in 100-foot increments, round upwards when necessary. Do not specify ceilings of 200 feet or less.
b. Visibility. Specify a visibility value equal to the distance measured directly from the DER to the obstruction, rounded to the next higher reportable value. The minimum value that may be specified is 1 SM; the maximum value that may be specified is 3 SM.

13-1-6. Initial Climb Area (ICA). The ICA is an area centered on the runway centerline extended used to evaluate obstacle clearance during the climb to 400 feet above DER rounded to the nearest foot, with a minimum climb gradient of 200 ft/NM.
a. ICA terms.
(1) ICA baseline (ICAB). The ICAB is a line extending perpendicular to the RCL
± 500 at DER. If a clearway is present, the ICAB is a line perpendicular to the extended RCL at the clearway end. It is the origin of the ICA (see Figure 13-1-5).
(2) ICA end-line (ICAE). The ICAE is a line at the end of the ICA perpendicular to the RCL extended. The splay of 15 degrees and length of the ICA determine its width (see Figure 13-1-5).
b. Area.
(1) Length. The ICA length is normally 2 NM, measured from the ICAB to the ICAE along RCL extended. It may be less than 2 NM in length for early turns by publishing a climb gradient. The ICA may be extended beyond 2 NM to maximum length of 10 NM. A specified altitude (typically 400 feet above DER) or the interception of PCG route must identify the ICAE.
(2) Width. The ICA origin is 1000 feet (± 500 perpendicular RCL) wide at its origin. The area splays outward at a rate of 15 degrees relative to the departure course (normally RCL
 
SteelChair
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Re: How soon after takeoff can an airliner safely start a turn?

Sat Oct 02, 2021 12:32 am

I remember watching takeoffs at ORD (in the 80s?) on one of the crosswind runways (22L/4R?) and they turned so aggressively immediately after takeoff that I thought they were going to drag a wingtip. It was a routine procedure....I think there was a potential conflict with another runway. There was a road parallel to the runway so you were fairly close. It was probably a VFR procedure only. It appeared that the pilots enjoyed it.
 
N47
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Re: How soon after takeoff can an airliner safely start a turn?

Sat Oct 02, 2021 1:18 am

N353SK wrote:
the National 7 Departure out of DCA where, upon departing runway 1, the SID instructs a left turn as soon as practical. This is a departure where we'd start the turn as soon as we're airborne.


Yea thats one where i would really want to make sure i start the turn ASAP.

I wonder what the departure out of RWY31 at kai tak was like especially with all those havies.
 
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Aaron747
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Re: How soon after takeoff can an airliner safely start a turn?

Sat Oct 02, 2021 2:36 am

N47 wrote:
N353SK wrote:
the National 7 Departure out of DCA where, upon departing runway 1, the SID instructs a left turn as soon as practical. This is a departure where we'd start the turn as soon as we're airborne.


Yea thats one where i would really want to make sure i start the turn ASAP.

I wonder what the departure out of RWY31 at kai tak was like especially with all those havies.


You can see it here:

https://www.youtube.com/watch?v=wIVjmf0L-aQ

Rwy 31 departures were not a picnic - high terrain right behind the dense city area behind the HKG terminal and limited room to maneuver in an engine out situation. Rwy 31 departures were also weight limited for heavies because the DT on Rwy 13 made 31's usable length around 9400'. Because of this there were times rwy 13 departures were preferred up to a 7-8 knot tailwind IIRC.
 
phllax
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Re: How soon after takeoff can an airliner safely start a turn?

Mon Oct 04, 2021 6:35 pm

N353SK wrote:
N1120A wrote:
adipasqu wrote:

Okay, maybe they are climbing so fast to 400' AAL that it seems like a quick turn, when it is not. A minimum climb of 340' per NM to 2100 on RWY 15 for OROSZ 2 and SLAPP 2 means that turn is starting no later than just over 1 NM from the end of the pavement. That's not very far.


Both SIDs publish the turn at the end of the runway. It isn't hard to get to 400' AAL from a 800-900' elevation airport from a 6900' runway for the airplanes that operate at BUR.


Both of those SIDs predicate their obstacle clearance on the assumption that the pilot will begin the turn at 400' AGL and comply with the charted climb gradients (on the SLAPP 2 from Runway 15, 340 feet per nautical mile to 2100). If turning at 400' AGL is not adequate for obstacle clearance, the SID will specify an altitude or fix at which the turn will commence. If an immediate turn is required the SID will include the phrase "turn left (right) as soon as practicable." For further details see AIM 5-2-9 paragraph e.1.


If you're driving down Empire which is on the other side of the fence or Vanowen (the street on the other side of the railroad tracks,) they often start the initial turn over them.

You guys know there's a terrible fight from the folks in Studio City over the new departure procedures which have them go and fly parallel over Mullholland until approx the 405 when you turn North and fly out of the Valley. I live in Valley Glen and have noticed more departures doing the (old) tight quick turn, and not just the Eastbound departures to LAS or JFK. The AS flight to SEA on Saturday afternoon did a quick turn.
 
bigb
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Re: How soon after takeoff can an airliner safely start a turn?

Mon Oct 04, 2021 7:55 pm

A lot of 121 operators use 400 AGL as a standard based on TERPs, unless you have a special qualification airport that requires turns lower than 400 AGL like DCA when departing runway 01 as soon as reaching 100 agl.
 
ThalesCoelho
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Re: How soon after takeoff can an airliner safely start a turn?

Tue Oct 05, 2021 3:27 am

Take a look at Rio de Janeiro/Santos Dumont (SBJ/SDU) take-off. Right after lift off, the airliners bank to the left.

https://www.youtube.com/watch?v=Fa3dEcfP6TY
 
GalaxyFlyer
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Re: How soon after takeoff can an airliner safely start a turn?

Tue Oct 05, 2021 3:31 am

Santos Dumont is great fun to operate out of. Not for the faint of heart at times, a problem at V1 could easily result in a swim, taking off toward Sugarloaf in rain can be interesting, but the arrival inside Corcovado is breathtaking.

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