B737 Approach Flaps Sequence
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B737 Approach Flaps Sequence
Our standard is to call "Flaps 25, speed 140", then "Flaps 30, Landing cklist".
I was told in the States it is common to call directly for Flaps 30 after Flaps 15.
I wish we could do the same here.
No need to bother with Flaps 25!
I was told in the States it is common to call directly for Flaps 30 after Flaps 15.
I wish we could do the same here.
No need to bother with Flaps 25!
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Our SOP's call for flap 15 to flap 30 or 40 directly. Shouldnt be a problem if you are not exceeding placard speed should it? After selecting gear down (and normally flap 15) we call for the landing checklist to flaps and then when final flap is selected we complete the checklist. Seems to work fine, frequently will ask for 'non-standard' flap 25 if deemed more appropriate before landing flap is selected.
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Well, Flaps 2 are totally useless and I think nobody in the world uses them.
The differences in Airlines SOP are a matter of culture, and , in the small ones, often depend also on the habits of the guy in charge,(
);
calling directly Flaps 30 after 15 just saves some workload.
I have seen also people calling directly Flaps5 after the clean config: is that in anybody's else standard?
Thanks
The differences in Airlines SOP are a matter of culture, and , in the small ones, often depend also on the habits of the guy in charge,(
);calling directly Flaps 30 after 15 just saves some workload.
I have seen also people calling directly Flaps5 after the clean config: is that in anybody's else standard?
Thanks
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Hi LEM,
Yes, I was aware of Flaps 2, talking to a real 737-200 captain he told me that he didn't even know why Boeing bother to put that setting.
Thanks a lot for the explanation about differences in SOPs.
Regards,
Bruno
Yes, I was aware of Flaps 2, talking to a real 737-200 captain he told me that he didn't even know why Boeing bother to put that setting.
Thanks a lot for the explanation about differences in SOPs.
Regards,
Bruno
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Our standard procedure here at our US airline is "flaps 5", "Landing Gear down, flaps 15, final descent checklist", "flaps 25", "flaps 30" (or 40).
We do use flaps 1 to maneuver down to 190KTS and flaps 5 to fly at 180. Flaps 10 are used when ATC assigns us 170 kts away from the field. Flaps 2 used to be used when we had the old block speeds but has shown to be of little to no value. I haven't used it in a few years now.
Hope this helps.
There are a lot of ways to "skin a cat" or fly an airplane.
K:
We do use flaps 1 to maneuver down to 190KTS and flaps 5 to fly at 180. Flaps 10 are used when ATC assigns us 170 kts away from the field. Flaps 2 used to be used when we had the old block speeds but has shown to be of little to no value. I haven't used it in a few years now.
Hope this helps.
There are a lot of ways to "skin a cat" or fly an airplane.
K:
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1-...Yes, I was aware of Flaps 2, talking to a real 737-200 captain he told me that he didn't even know why Boeing bother to put that setting.
2-...Well, Flaps 2 are totally useless and I think nobody in the world uses them.
Hey buddies... ok, flaps 2 can be useless during approach.
However, there're takeoff performance data for flaps 2 and 25 in the Boeing 737-200 Advanced Operations Manual. So, that's why those settings are there.
I've already used them....
2-...Well, Flaps 2 are totally useless and I think nobody in the world uses them.
Hey buddies... ok, flaps 2 can be useless during approach.
However, there're takeoff performance data for flaps 2 and 25 in the Boeing 737-200 Advanced Operations Manual. So, that's why those settings are there.
I've already used them....
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You are right, Bokomoko, I checked in my old -228 manuals.
My original point was that it is acceptable to call directly Flaps5 after the clean config. if one wishes so, and Flaps 30 after 15, that there are no technical reasons that prohibit so.
Since this is one of the areas not covered by the SOP of certain small companies (and even bigger ones), if my boss shouts at me that I have to transition through Flaps1 and also Flaps 25, it seems I can tell him his absolute truth is only true to him, and around the world experienced professionals do it in other ways...
My original point was that it is acceptable to call directly Flaps5 after the clean config. if one wishes so, and Flaps 30 after 15, that there are no technical reasons that prohibit so.
Since this is one of the areas not covered by the SOP of certain small companies (and even bigger ones), if my boss shouts at me that I have to transition through Flaps1 and also Flaps 25, it seems I can tell him his absolute truth is only true to him, and around the world experienced professionals do it in other ways...
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You are correct LEM in that there is no technical reason (that I could find) why you should pause at flap 1 and 25.
Our SOP calls for us to stop at 1 and 25 anyway.
and
Flap 2 is for take-off. We use it on a daily basis out of CYVP.
cheers
BBB
Our SOP calls for us to stop at 1 and 25 anyway.
and
Flap 2 is for take-off. We use it on a daily basis out of CYVP.
cheers
BBB
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My understanding of the 'football' is that flaps 2 improved cilmb(overrun) take-off probably allows the highest weight from a 6500'-7500' rwy. However, contrary to one of the posts above, I don't believe that F25 is used for take-off on ADV, and the highest might be F15 which is also the secondary landing flap setting.
On the approach, flaps 2 can also be selected to slow down to 180 kts (non-std), provided your plane has RPR (Rudder Pressure Reducer) which reduces the hydraulic pressure available to the rudder at low altitudes and with it chances of uncomanded yaw. Although, judging by higher block speeds mentioned above, it seems that some operators may still not have RPRs installed. Generally, all flaps settings can be used on approach and they roughly allow you to slow down 10 kts (provided you have RPRs). The actual maneuvering speeds corresponding to your weight (as used on 727, 757, 767,..) are a lot lower, but the block speeds on the 737 err on the safe side as they take the highest weight and were meant to simplify things.
As for the reason for stopping at F1 and F25 on the approach, I can think of a few reasons. One is to confirm the position of the LEDs/slats. Keep in mind that all except 2 extend at F1, but at F25 you get full extension in basics and F10 in ADV. Two is to avoid large trim changes at low altitudes causing possible trim runaways, not to mention passenger discomfort. Also you spot and stop a flaps assymetry sooner, should one happen. Since regardless of a higher position selected the flaps will go through the motion anyway, why not take the time and the safe practice of confirming their position with each selection. (In fact in the old days they used to keep their hand on the handle until they got what they selected). Normal landing flap setting is F30, and F40 is only used in adverse wx, short rwys,....requiring slower app speeds. However, F40 gate is locked off permanently in stage 3 certification to comply with noise restriction on possible GAs. I guess the folks that still use F40 for landing are not stage 3 certified?
P.S. I don't think the commonality issue is a factor for having F2 position in 737, since there is no F1 in 727 and F2 is the first position. Also the practice of selecting F5 directly would be a very dangerous habit not to confirm LEDs/slats extension at F1, and very unnecessary high load on the flaps motor. Remember that we select flaps for the speed at which we want to fly, we don't use them as speed brakes to slow down. Hope this helps folks.
On the approach, flaps 2 can also be selected to slow down to 180 kts (non-std), provided your plane has RPR (Rudder Pressure Reducer) which reduces the hydraulic pressure available to the rudder at low altitudes and with it chances of uncomanded yaw. Although, judging by higher block speeds mentioned above, it seems that some operators may still not have RPRs installed. Generally, all flaps settings can be used on approach and they roughly allow you to slow down 10 kts (provided you have RPRs). The actual maneuvering speeds corresponding to your weight (as used on 727, 757, 767,..) are a lot lower, but the block speeds on the 737 err on the safe side as they take the highest weight and were meant to simplify things.
As for the reason for stopping at F1 and F25 on the approach, I can think of a few reasons. One is to confirm the position of the LEDs/slats. Keep in mind that all except 2 extend at F1, but at F25 you get full extension in basics and F10 in ADV. Two is to avoid large trim changes at low altitudes causing possible trim runaways, not to mention passenger discomfort. Also you spot and stop a flaps assymetry sooner, should one happen. Since regardless of a higher position selected the flaps will go through the motion anyway, why not take the time and the safe practice of confirming their position with each selection. (In fact in the old days they used to keep their hand on the handle until they got what they selected). Normal landing flap setting is F30, and F40 is only used in adverse wx, short rwys,....requiring slower app speeds. However, F40 gate is locked off permanently in stage 3 certification to comply with noise restriction on possible GAs. I guess the folks that still use F40 for landing are not stage 3 certified?
P.S. I don't think the commonality issue is a factor for having F2 position in 737, since there is no F1 in 727 and F2 is the first position. Also the practice of selecting F5 directly would be a very dangerous habit not to confirm LEDs/slats extension at F1, and very unnecessary high load on the flaps motor. Remember that we select flaps for the speed at which we want to fly, we don't use them as speed brakes to slow down. Hope this helps folks.
Last edited by wellthis; 18th Sep 2003 at 13:51.
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wellthis,
thanks for your reply about the originals.
On classics Flaps 2 operations are totally ignored by the manuals.
I agree on your point regarding the stress involved on the motor if calling directly F5, even if I think it's not that stressful because you are slowing down anyway.
But I don't see the danger of the practice of selecting F5 directly would be a very dangerous habit not to confirm LEDs/slats extension at F1 .
Could you explain more?
In the Asymmetrical or no leading edge devices non-normal cklist you are gonna land with F15 anyway, just adding 5 knots.
Where do you see such a great danger?
Thankyou
thanks for your reply about the originals.
On classics Flaps 2 operations are totally ignored by the manuals.
I agree on your point regarding the stress involved on the motor if calling directly F5, even if I think it's not that stressful because you are slowing down anyway.
But I don't see the danger of the practice of selecting F5 directly would be a very dangerous habit not to confirm LEDs/slats extension at F1 .
Could you explain more?
In the Asymmetrical or no leading edge devices non-normal cklist you are gonna land with F15 anyway, just adding 5 knots.
Where do you see such a great danger?
Thankyou
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It is dangerous in the way that one does not get a confirmation of LED/slats movement. Suppose one get no LEDs and continues slowing down to 170 kts, in the turn to final if one is heavy and sloppy with speed control, one might get the shaker. Also, if an assymetry were to occur betwwen F0 & F1, one may not be able to stop the problem and could continue in assymetry and increase the roll tendencies. The first flap gate in any airplane is very important for movement confirmation and one should stop to check. Those that feel rushed on the app with all the flap selections, should select them and get stabilized sooner until they feel more comfortable with the airplane. The profiles are the result of many flight hours test and provide the safest most efficient approach, therefore they should be followed I believe.
As for F2 position, those operators that ignore it may be for cost savings on rwy analysis as it probably gave them little advantage for the fields they use, otherwise they have voluntarily deprived themselves of a very versatile TO flap setting and tons of extra pay load. As I said, 6500'-7500' rwys are best served by flaps 2. Hope this helps.
As for F2 position, those operators that ignore it may be for cost savings on rwy analysis as it probably gave them little advantage for the fields they use, otherwise they have voluntarily deprived themselves of a very versatile TO flap setting and tons of extra pay load. As I said, 6500'-7500' rwys are best served by flaps 2. Hope this helps.
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There was one interesting advantage of using flap 2 instead of flap 1 for take off in the 737-100 and 200. If you inadvertently selected flaps 1 to flaps up at V2 +15 knots instead of at block speed 190 knots (depending on weight of course) then you could be in strife very quickly. On the other hand by using flap 2 for take off (and you lost very little performance over flap 1 anyway), you would select flap 1 at V2+15 and the rest followed logically.
Flap 25 was a very useful take off setting if the runway surface was very rough and you needed to get into the air as soon as possible to avoid shaking the hell out of the poor old Boeing. Some of the early coral runways on Pacific atolls were rough as guts.
Also flap 25 was a useful setting for take off on a wet runway where full thrust was required and you would have a nice low V1 to pull up from in an abort.
Flap 25 was a very useful take off setting if the runway surface was very rough and you needed to get into the air as soon as possible to avoid shaking the hell out of the poor old Boeing. Some of the early coral runways on Pacific atolls were rough as guts.
Also flap 25 was a useful setting for take off on a wet runway where full thrust was required and you would have a nice low V1 to pull up from in an abort.
