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convair880mfan
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SOP flap/slat movement on the DC-10

Tue Jul 20, 2021 8:58 pm

I don't a have a Flight Manual for the DC-10 and don't do flight simulation so I am wondering if there are any former DC-10 pilots out there who can answer this question:

When in the approach, are DC-10 slats lowered first followed by a delay until speed decays when flaps can be lowered a notch or are slats and flaps lowered simultaneously? I imagine that conditions factor into all this, like gross weight at takeoff and such. Couldn't find a photo of the flaps placard for the DC-10.

I know that after takeoff slats are selected in after flaps are up and also know that the DC-10 had a Dial-A-Flap feature. I have read the articles here on the subject of "flaps up/flaps zero."

Was it difficult to "slow down" the DC-10? I imagine this also depends on conditions.
 
VMCA787
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Re: SOP flap/slat movement on the DC-10

Tue Jul 20, 2021 9:22 pm

NW, in the name of standardization, didn't have the dial a flap system on their 40s. It was a Rube Goldberg system that was a real pain. TBH, I was on the 747 by the time the -30s arrived so I don't know if that was changed. I would assume it was.
Fly fast, live slow!
 
CosmicCruiser
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 12:17 am

It's been a while since I flew a DC-10 but I don't remember it being a big deal. It was only for T/O flaps and the after T/O chk list had you zero out the dial. If you forgot you would be surprised when you selected LDG flaps.
 
CosmicCruiser
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 12:17 am

It's been a while since I flew a DC-10 but I don't remember it being a big deal. It was only for T/O flaps and the after T/O chk list had you zero out the dial. If you forgot you would be surprised when you selected LDG flaps.
 
Max Q
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 4:53 am

If the DC10 flap / slat lever was the same as the MD80 it took a bit of getting used to

Flap selections were made with the lever but to retract the slats you needed to reach underneath the handle and release a separate ‘ trigger’

It took a separate and deliberate action which was easy once you’d got the hang of it, just different than Boeing and actually a good feature, with a significant increase in stall speed with slat retraction MD ensured you really wanted the slats retracted
The best contribution to safety is a competent Pilot.


GGg
 
113312
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 10:52 am

On the DC-10, the flap and slat handles are mechanically linked. For takeoff, a dial-a-flap setting is calculated and preselected. Preparing for takeoff, the handles are moved to lock into the Dial-A-Flap detent and this extends both the slats and trailing edge flaps. During climbout, the flaps are retracted in one step to zero with the slats remaining extended. At the appropriate airspeed, the handles are released through a gate to retract the slats.
For the approach to land, the handles are first moved to the Slats Extended/Flaps Zero detent. Subsequently, as the airspeed slows, flaps 15, 22, 35 and 50 are selected.

Should the slats jam or fail to extend inflight, the handles can be separated so that the slat selection remains retracted and the trailing edge flaps may be extended per the abnormal procedure. Approach speed and pitch attitude are affected.
 
CosmicCruiser
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 1:50 pm

CosmicCruiser wrote:
It's been a while since I flew a DC-10 but I don't remember it being a big deal. It was only for T/O flaps and the after T/O chk list had you zero out the dial. If you forgot you would be surprised when you selected LDG flaps.


I guess I should have clarified I was talking about the dial a flap but yes the flap/ slat handle(s) did take a little getting used to. The practice was to put your fingers under the slat handle and lift up which would raise the flap handle too. Then there was the flap/ no slat landings that required separating the two handles.
 
LH707330
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Re: SOP flap/slat movement on the DC-10

Wed Jul 21, 2021 6:34 pm

Did McDac actually call the system "dial-a-flap" as well, or is that pilot slang?
 
Max Q
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 5:19 am

113312 wrote:
On the DC-10, the flap and slat handles are mechanically linked. For takeoff, a dial-a-flap setting is calculated and preselected. Preparing for takeoff, the handles are moved to lock into the Dial-A-Flap detent and this extends both the slats and trailing edge flaps. During climbout, the flaps are retracted in one step to zero with the slats remaining extended. At the appropriate airspeed, the handles are released through a gate to retract the slats.
For the approach to land, the handles are first moved to the Slats Extended/Flaps Zero detent. Subsequently, as the airspeed slows, flaps 15, 22, 35 and 50 are selected.

Should the slats jam or fail to extend inflight, the handles can be separated so that the slat selection remains retracted and the trailing edge flaps may be extended per the abnormal procedure. Approach speed and pitch attitude are affected.



Interesting

Thanks for the description
The best contribution to safety is a competent Pilot.


GGg
 
Max Q
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 5:27 am

CosmicCruiser wrote:
CosmicCruiser wrote:
It's been a while since I flew a DC-10 but I don't remember it being a big deal. It was only for T/O flaps and the after T/O chk list had you zero out the dial. If you forgot you would be surprised when you selected LDG flaps.


I guess I should have clarified I was talking about the dial a flap but yes the flap/ slat handle(s) did take a little getting used to. The practice was to put your fingers under the slat handle and lift up which would raise the flap handle too. Then there was the flap/ no slat landings that required separating the two handles.



I think it was a similar movement on the MD80, we didn’t have any procedure to separate the handles however

The slat design on the -80 was completely different than my previous aircraft, the 727 with its numerous segmented sections, you never pushed the limits on its maximum extension speeds (bad airmanship anyway) if you did you’d get a lot of vibration


But the MD80 slat was just one giant, continuous section on each wing and soon after transitioning to it I noticed guys extending the slats right at their limit speed and there was basically no vibration at all


I still never did that, slats and flaps are used to allow you to fly slower, not to slow you down but it was interesting that it didn’t seem to bother the aircraft


The speed brakes on the MD80 were not very effective however and lowering the gear just increased the noise level
The best contribution to safety is a competent Pilot.


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Max Q
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 5:32 am

LH707330 wrote:
Did McDac actually call the system "dial-a-flap" as well, or is that pilot slang?



No, it was referred to in our flight manual as ‘Dial a flap’ that was the official term


You ‘dialed’ in a pre-planned flap setting for take off. We rarely used it, the only airport I remember using it from was Mexico City with its high elevation we would use a dial a flap setting of just 4 degrees ( with slats of course)
The best contribution to safety is a competent Pilot.


GGg
 
extender
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 1:19 pm

Max Q wrote:

The slat design on the -80 was completely different than my previous aircraft, the 727 with its numerous segmented sections, you never pushed the limits on its maximum extension speeds (bad airmanship anyway) if you did you’d get a lot of vibration


But the MD80 slat was just one giant, continuous section on each wing and soon after transitioning to it I noticed guys extending the slats right at their limit speed and there was basically no vibration at all


The DC-10 Slats are pretty much the same thing, with the exception of the gap for the pylon. The 727 had that funky 2/3 & 6/7 slats extending first, retracting last.

The dial a flap was an actual serrated wheel aft of the flap/slat lever.

Image
 
LH707330
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 4:19 pm

Max Q wrote:
LH707330 wrote:
Did McDac actually call the system "dial-a-flap" as well, or is that pilot slang?



No, it was referred to in our flight manual as ‘Dial a flap’ that was the official term


You ‘dialed’ in a pre-planned flap setting for take off. We rarely used it, the only airport I remember using it from was Mexico City with its high elevation we would use a dial a flap setting of just 4 degrees ( with slats of course)

Thanks for that explanation!
 
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Horstroad
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 6:34 pm

extender wrote:
The DC-10 Slats are pretty much the same thing, with the exception of the gap for the pylon.
The dial a flap was an actual serrated wheel aft of the flap/slat lever.

Image




When reading this thread I thought to myself "this must be the same thing like on the MD-11" (which I'm quite familiar with). But I googled for a photo of the DC-10 flap handle and was surprised that it actually looks very different:

DC-10:
Image
Source: https://www.airteamimages.com/mcdonnell ... large.html



MD-11:
Image
Source: https://www.airliners.net/photo/Finnair ... -11/605846



Why are there two handles? Are flaps and slats handles actually separated as I understand it from this post?
113312 wrote:
On the DC-10, the flap and slat handles are mechanically linked.
[...]
Should the slats jam or fail to extend inflight, the handles can be separated so that the slat selection remains retracted and the trailing edge flaps may be extended per the abnormal procedure.

If yes, which one is which? And why do both handles go all the way to 50, when the slats only operate between flaps 0 and slats retract?
Or is that thing to the right of the flap handle not a separate handle, but part of the dial-a-flap feature, similar to the small indicator next to the MD-11 flap handle?


How does the dial-a-flap feature work on the DC-10? The flap handle has set detents at 0, 15, 22, 35 and 50 degrees while the MD-11 has a moveable detent between 10 and 25 (which is directly controlled by the dial) in addition to the 'Flaps Up/Slats Retract', 0, 28, 35 and 50 degree detents.
 
VMCA787
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Re: SOP flap/slat movement on the DC-10

Thu Jul 22, 2021 8:33 pm

The DC-10 pic you have is of a DC10-40 which would have been a NW aircraft. That is a very different set up than all the other operators.
Fly fast, live slow!
 
CosmicCruiser
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Re: SOP flap/slat movement on the DC-10

Fri Jul 23, 2021 2:04 am

.
 
113312
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Re: SOP flap/slat movement on the DC-10

Fri Jul 23, 2021 2:58 am

If you look closely to the photograph of the DC-10 Flap/Slat handles, you will see that there are markings for each: Flaps 0/15/22/35/50 and Slats: TO EXT & LAND EXT. The slat handle travels with the flap handle unless it is mechanically unlocked.
With regard to the Dial-A-Flap, the selection wheel controls an internal notch that the handle will drop into when the handles are moved. This way you are not limited to the flap notches seen in the photo, for takeoff. While you could use a flap setting of 15 degrees for takeoff, takeoff performance might call for 3 degrees, or 13 degrees or 18 degrees which can only be positively selected using the Dial-A-Flap selector.

By procedure, following flap/slat retraction in the climb, the Dial-A-Flap wheel is returned to full UP to get it's detent out of the way in anticipation of only using the regular positions during approach for landing.
 
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Horstroad
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Re: SOP flap/slat movement on the DC-10

Fri Jul 23, 2021 8:52 pm

VMCA787 wrote:
The DC-10 pic you have is of a DC10-40 which would have been a NW aircraft. That is a very different set up than all the other operators.

That's the only clear photograph of a DC-10 flap handle I could find online. Does anyone have one of the regular config?

113312 wrote:
With regard to the Dial-A-Flap, the selection wheel controls an internal notch that the handle will drop into when the handles are moved.

That's how I know it from the MD-11. There you have the wide detent from 10-25 degrees where the flap lever can travel guided by the moveable detent.

113312 wrote:
While you could use a flap setting of 15 degrees for takeoff, takeoff performance might call for 3 degrees, or 13 degrees or 18 degrees which can only be positively selected using the Dial-A-Flap selector.

Does the flap handle not fall in the detents? For example when you move the dial-a-flap selector from 13 degrees to 18 degrees, the flap handle would drop in the 15 degrees detent, wouldn't it? Or is it just the the photo of the abnormal NW config that's confusing me?
 
JustAnFO
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Re: SOP flap/slat movement on the DC-10

Mon Jul 26, 2021 10:55 pm

VMCA787 wrote:
The DC-10 pic you have is of a DC10-40 which would have been a NW aircraft. That is a very different set up than all the other operators.

Are you quite sure about that? The comm radio heads seem to be military (labled "V/UHF" and "NET"), and the TACAN nav radio head certainly wouldn't exist on a NWA DC-10 either.
 
JustAnFO
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Re: SOP flap/slat movement on the DC-10

Mon Jul 26, 2021 11:13 pm

Horstroad wrote:
VMCA787 wrote:
The DC-10 pic you have is of a DC10-40 which would have been a NW aircraft. That is a very different set up than all the other operators.

That's the only clear photograph of a DC-10 flap handle I could find online. Does anyone have one of the regular config?

FedEx MD-10-10s and -30s (derived from their respective DC-10 series, as you know) have an identical flap/slat handle, including the Dial-A-Flap Selector. But as I noted above, that photo seems to be of a KC-10, not a NWA DC-10-40.

113312 wrote:
While you could use a flap setting of 15 degrees for takeoff, takeoff performance might call for 3 degrees, or 13 degrees or 18 degrees which can only be positively selected using the Dial-A-Flap selector.

Does the flap handle not fall in the detents? For example when you move the dial-a-flap selector from 13 degrees to 18 degrees, the flap handle would drop in the 15 degrees detent, wouldn't it? Or is it just the the photo of the abnormal NW config that's confusing me?[/quote]
The flap handle (ok, technically I think it's the slat handle, but so long as the flap and slat handles are connected together in their normal config, let's consider it as one handle) does indeed drop into the detents, but it's not procedure to move the Dial-A-Flap selector while the flap/slat handle is in the Dial-A-Flap detent.

Before takeoff, the Dial-A-Flap selector is set to the desired position, and then the flap/slat handle is moved from UP/RET directly to the Dial-A-Flap/EXT detent. After takeoff, the flap/slat handle is moved from the Dial-A-Flap/EXT to 0/EXT, then onward to UP/RET. As a matter of housekeeping, the DAF selector is moved to the 0° position, as it's no longer used for the rest of the flight.

The sequence during landing starts at UP/RET and then to 0/EXT, 15/EXT, 22/EXT, 35/EXT, and optionally, 50/EXT. Dial-A-Flap is not used.
 
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Horstroad
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Re: SOP flap/slat movement on the DC-10

Tue Jul 27, 2021 1:36 pm

The flap handle (ok, technically I think it's the slat handle, but so long as the flap and slat handles are connected together in their normal config, let's consider it as one handle) does indeed drop into the detents, but it's not procedure to move the Dial-A-Flap selector while the flap/slat handle is in the Dial-A-Flap detent.

Before takeoff, the Dial-A-Flap selector is set to the desired position, and then the flap/slat handle is moved from UP/RET directly to the Dial-A-Flap/EXT detent. After takeoff, the flap/slat handle is moved from the Dial-A-Flap/EXT to 0/EXT, then onward to UP/RET. As a matter of housekeeping, the DAF selector is moved to the 0° position, as it's no longer used for the rest of the flight.

The sequence during landing starts at UP/RET and then to 0/EXT, 15/EXT, 22/EXT, 35/EXT, and optionally, 50/EXT. Dial-A-Flap is not used.[/quote]
So it's basically just like the MD-11, except the DC-10 has a 22 degree detent instead of a 28 degrees detent. Thanks for the explanation.
 
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LyleLanley
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Re: SOP flap/slat movement on the DC-10

Tue Jul 27, 2021 9:58 pm

JustAnFO wrote:
But as I noted above, that photo seems to be of a KC-10, not a NWA DC-10-40.


It's definitely not a KC-10. If I had to guess, it's either the Omega DC-10-40 or the Dutch KDC-10 before they updated their cockpit to glass-ish.
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