Airspeed references

[Superpilotv2 2]

Hi guys, after a long time I managed it to get my hands down on the good old PMDG 737-600. But I have a little thing I can´t recall corectly. Whan I deploy the flaps some reference markings come into sight on the speedtape with the flap setting. I don´t know when I have to deploy the flap. For exapmle when the "clear" marking is on 201 KTS and the "1" marking is at 183 KTS, when do I have to deploy the flaps then? After passing the "clear" marking or after "1"? Btw. great little plane. Thus of it´s age, it´s wonderful to fly.

[Spin737 102]

Slowing for approach, you'd select F1 before slowing below the flaps up speed. The speed you see on the tape is called the maneuvering speed and it gives you good stall protection if you abide by it. So, don't go below the F0 maneuvering speed until you have selected F1.However, on Takeoff, you do select the next flap setting before you reach its speed.

[Superpilotv2 2]

Slowing for approach, you'd select F1 before slowing below the flaps up speed. The speed you see on the tape is called the maneuvering speed and it gives you good stall protection if you abide by it. So, don't go below the F0 maneuvering speed until you have selected F1.However, on Takeoff, you do select the next flap setting before you reach its speed.

Manouvering speed is also the minimum speed for this setting. In case of the clear setting it´s the lowest speed at which should be flown with fllaps up? Am I right on that?

[rocketfs 2]

Manouvering speed is also the minimum speed for this setting. In case of the clear setting it´s the lowest speed at which should be flown with fllaps up? Am I right on that?

Steffen,I don't agree with Matt's answer about the Takeoff flaps retract schedule. You only select the next flap setting AFTER you reached that flap speed.PMDG manual 10_Flight Techniques page 10-6I don't understand your question "Manouvering speed is also the minimum speed for this setting. In case of the clear setting it´s the lowest speed at which should be flown with fllaps up? Am I right on that?"The lowest speed with flaps up is the minimum clean speed.Bert Van Bulck

[Chock 17,769]

Maneuvering Speed (Va) is the advertised maximum speed at which you can fully deflect the control surfaces without overstressing the airframe to potentially cause structural damage. It does not necessarily mean it is safe to do that though, since you could put the thing beyond the stall angle with the stick all the way back, and it is also possible to overload the structure by rapidly going from one deflection to the opposite deflection even at or below the maneuvering speed. Va changes depending on weight, typically increasing as the weight of the aeroplane goes up.On an average airliner, Va would probably be somewhere between about 50-70 knots above V2, but in practice many airliners put automatic limits on deflection of the control surfaces, although you should not rely on that fact.The most famous instance of someone going for too much control deflection above a safe maneuvering speed would be the American Airlines Airbus 330 (Flight AA587) that crashed in Queens, NY in late 2001. Although in fact what actually caused the break up of the tail surface was not merely a single excessive control deflection, but the aerodynamic loads placed on the tail from repeated deflections from side to side by the pilot whilst he was ill-advisedly over-controlling the aircraft in an attempt to cancel out some turbulence. Doing that effectively levered the tail off the aircraft in a manner similar to how you might try to snap a plank of wood by bending it backwards and forwards repeatedly.AA altered their training programme following the investigation into the loss of AA587, so that pilots would be more aware of how easy it is to put too much side load on the vertical stabiliser. I can certainly sympathise with the pilot who caused that crash though, because I recall being shouted at by an instructor once when I gave it too much rudder on an aircraft right up near Vne on one occasion when I didn't know any better. Of course he should have explained that to me prior to us actually flying because I was a new student pilot back then, and it was him who put us up at that speed in a long shallow descent back to the airfield and then handed control to me, but even so, it does illustrate that you do have to be careful with controls.Al

[fencer 16]

The most famous instance of someone going for too much control deflection above a safe maneuvering speed would be the American Airlines Airbus 330 (Flight AA587) that crashed in Queens, NY in late 2001.

Al,As you probably know full well, it was an A300, not an A330...Probably a typo?Bruno

[Spin737 102]

I'm not sure what the PMDG manual says. I only care from Boeing and my airline say, and they say as I said already. Sim if you want, but I speak from having flown 4 legs in a 737-800 today. I'm tired and I have no days off for 18 days. Enjoy the Alt-F4.

[Spin737 102]

With airspeed increasing, subsequent flap retractions should be initiated whenairspeed reaches the maneuver speed for the existing flap position. The maneuverspeed for the existing flap position is indicated by the numbered flap maneuverspeed bugs on the airspeed display.- Boeing Flight Crew Training Manual

[rocketfs 2]

I'm not sure what the PMDG manual says. I only care from Boeing and my airline say, and they say as I said already. Sim if you want, but I speak from having flown 4 legs in a 737-800 today. I'm tired and I have no days off for 18 days. Enjoy the Alt-F4.

Sorry Matt, didn't realise you are a pilot. So you raise them just before reaching it's speed or well in advance?I guess you only do that when there is a reasonable chance you keep accelerating?Best Regards,Bert Van Bulck

[Spin737 102]

Bert,Boy was I cranky and tired when I wrote that! Most people look to see that the trend indicator shows an acceleration and that you're above the V2+15 ("sharktooth"). Some guys I've flown with wait until the tip of the trend indicator is touching the next flap speed.Here's more of what Boeing says from the Flight Crew Training Manual:

During flap retraction, selection of the next flap position is initiated when reachingthe maneuver speed for the existing flap position. Therefore, when the new flapposition is selected, the airspeed is below the maneuver speed for that flapposition. For this reason, the airspeed should be increasing when selecting the nextflap position. During flap retraction, at least adequate maneuver capability or 30°of bank (15° angle of bank and 15° overshoot) to stick shaker is provided at theflap retraction speed. Full maneuvering capability or at least 40° of bank (25° ofbank and 15° overshoot) is provided when the airplane has accelerated to therecommended maneuver speed for the selected flap position.Begin flap retraction at V2 + 15 knots, except for a flaps 1 takeoff. For a flaps 1takeoff, begin flap retraction when reaching the flaps 1 maneuver speed.With airspeed increasing, subsequent flap retractions should be initiated whenairspeed reaches the maneuver speed for the existing flap position. The maneuverspeed for the existing flap position is indicated by the numbered flap maneuverspeed bugs on the airspeed display.

[Superpilotv2 2]

Thanks Matt for your contributions. You help me understanding that plane better. For take-off it´s all clear now. But how about the approach. Have the flaps to be out before I reach the flap manouvering speed shown in the speedtape?

[Spin737 102]

Steffen,Thanks. I don't do much simming anymore, but many of the questions on this forum make me study, so I know the plane better, too. It's "win-win," as we Americans say.Don't slow below F0 airspeed until you have selected the flaps to 1. Don't slow below F1 until you select F5, etc.

[rocketfs 2]

Thanks for the info Matt, I appreciate it a lot!Bert Van Bulck

[Superpilotv2 2]

Steffen,Thanks. I don't do much simming anymore, but many of the questions on this forum make me study, so I know the plane better, too. It's "win-win," as we Americans say.Don't slow below F0 airspeed until you have selected the flaps to 1. Don't slow below F1 until you select F5, etc.

Thanks Matt. i´m away now, taking the 737 everywhere...