How to slow from 180 kts on five mile final

[clum 2]

Use more flaps :)

Not with the speedbrake I won't. Shouldn't be used with flaps set to greater than 10 (at least according to the training captain whom I've received instruction from on the Level-D sim).

I have a friend on the 737-3/400. He says you can descend, you can slow down, but you can't descend and slow down in those birds. Keeping in mind the -800 is even more slippery... I'm loving that sim pilots are finally realizing handling these turbojets isn't all that easy! I'm hating that it's looked at as a "bug".

While that may be true for other phases of flight, it doesn't hold up for final. If that were that case, every flight would have to intercept the glide at final approach speed! I get where you're coming from, but this is something entirely different. The long and short of it is, with the flight idle around 40% there is absolutely no way to slow down when on the glideslope, so I have to intercept at pretty close to final app speed. Again, there's no issue at around 30%, the speed bleeds off nicely. I think there's a problem for me there somewhere, be it with NGX, hardware, or ASE.

[PIC007 82]

Not with the speedbrake I won't. Shouldn't be used with flaps set to greater than 10. While that may be true for other phases of flight, it doesn't hold up for final. If that were that case, every flight would have to intercept the glide at final approach speed! I get where you're coming from, but this is something entirely different.

Why are you using the speedbrakes instead of flaps on final? Damn good way to bend an airplane.

[clum 2]

Why are you using the speedbrakes instead of flaps on final? Damn good way to bend an airplane.

You try selecting flaps 15+ when you're doing 180kts in a light aircraft. Dam good way to end up with 15 degrees of nose down pitch before the speed comes down. Anyway, I wouldn't use spoilers on final at all, rather it just serves the purpose of illustrating that there's nothing that will slow the aircraft down in this situation.

[ZachLW 37]

The long and short of it is, with the flight idle around 40% there is absolutely no way to slow down when on the glideslope, so I have to intercept at pretty close to final app speed. Again, there's no issue at around 30%, the speed bleeds off nicely. I think there's a problem for me there somewhere, be it with NGX, hardware, or ASE.

I was going to say, I'm not having any issues. I'm usually in VNAV mode during intercept, adding flaps incrementally when needed. The FMC does a fine job of planning. I'm also finding it much easier to slow down in your given situation than a lot of people. I'm just not sure Callum.

[PIC007 82]

You try selecting flaps 15+ when you're doing 180kts in a light aircraft. Dam good way to end up with 15 degrees of nose down pitch before the speed comes down. Anyway, I wouldn't use spoilers on final at all, rather it just serves the purpose of illustrating that there's nothing that will slow the aircraft down in this situation.

Have you actually checked the flap extension speeds? Att 180 kts you have room for plenty more. Between the gear and flaps the plane slows just fine here, you might want to rethink your procedures. Not sure why you consider the 737 a 'light aircraft' but to each his own.

[clum 2]

By "light" I am of course referring to the load/passenger weight of the aircraft, not the category. With only 5-6 tons of fuel and an empty load (say a positioning flight), 180kts will only require flaps 1 or 2, and with that it will be exhibit a nose pitch of pretty close to 0 degrees. Go and try that scenario and tell me what happens when you throw flaps 15+ at it. Again, the scenario I originally described was meant solely to illustrate that there is nothing that can be done to slow the aircraft when on an 800fpm decent at an N1 of 40%.

[ZachLW 37]

By "light" I am of course referring to the load/passenger weight of the aircraft, not the category. With only 5-6 tons of fuel and an empty load (say a positioning flight), 180kts will only require flaps 1 or 2, and with that it will be exhibit a nose pitch of pretty close to 0 degrees. Go and try that scenario and tell me what happens when you throw flaps 15+ at it. Again, the scenario I originally described was meant solely to illustrate that there is nothing that can be done to slow the aircraft when on an 800fpm decent at an N1 of 40%.

Except put the flaps in correctly.

[clum 2]

Sure Zach, but the problem is that the aircraft, once descending on the glide, won't slow to those flap speeds! Obviously I'm not going straight from flap 1 to 15.

[ZachLW 37]

Could you post a vid, Callum? I'm not being a smart alec, I just don't see a "problem" with the sim.

[clum 2]

I will do if I can't get to the bottom of it. I know you're not being a smart-alec, you're actually one of the better natured folk around here I think! I'm also not bashing the NGX in any way; I know this is my problem, yet there is surely something causing it other than technique. I've yet to try with FSUIPC removed completely, so that's the next stop before a vid.

[ZachLW 37]

Good luck! If I ever get around to installing FS Recorder, I'll post one as well.

[usmc3073 3]

I found in VNAV descents that the plane will always try to be a little low once you are getting close to your intercept alt the plane should level off allowing you to easily slow your speed put flaps out and gear down this will get you right where you need to be for intercept. I also will put in a speed restriction of about 225 this forces the plane to drop alt faster at the beginning of descent when I can use speed brakes (if there is a tailwind). by the time I am breaking 10000agl the plane is slower and descending gently.... it takes away some of the slippery "ness" of the plane. I don't know if its right but it works. Guthrie Z

[Paul Deemer 13]

I assume you meant OUTER marker not INNER, or you got problems !

Oooops you are correct, that was an error on my part.

[JC75 22]

Clum there lies your problem, a light aircraft will struggle to slow down more - not only because of the physics but also because in general you have more speed to loose to get to VREF - My experience of light postioning flights etc, is that they will often tell us thats the case, and they will then generally slow down a lot earlier before intercept and again once established really slow down - a 757 i worked the other day told me he would be doing 115kts final approach! So in your case you cant do the 210kts and get it to slow as easily especially if you intercepting in a descent - you need to intercept below the glide, bleed the speed there, applying flaps, then as you intercept the glide, gear down to add more drag as you pitch down...

[G550flyer 1,014]

a little excerpt from a flight manual on descent.737 Sec. 3 Page 147Flight Manual DESCENTA good descent profile takes into consideration many variables and can account for significant fuel savings.Maintaining the desired descent profile and utilizing the MAP mode (if available) to maintain awareness of position will ensure a more efficient operation. The crew should be aware of the destination weather and traffic situation and consider the requirements of a potential diversion. A review of the airport approach charts and pages, and a briefing for the approach and landing will be conducted. Complete this approach briefing as soon as practical, preferably before arriving at top of descent so the crew may give full attention to aircraft control.The ECON PATH descent with VNAV engaged should be used whenever possible. This will result in a CRUISE descent if initiated beyond 50 miles from T/D and a DES NOW descent if initiated within 50 miles of the T/D. The use of a VNAV descent is preferred over a descent utilizing vertical speed due to the reduced fuel burn. Flight deck workload increases as the aircraft descends into the terminal area. Distractions must be minimized, administrative and nonessential duties completed before descent or postponed until after landing. The earlier that essential duties can be performed, the more time will be available for the more critical approach and landing phases. Below 10,000’ MSL, limit programming of the FMC to minimize pilot head-down time.Traffic considerations and speed control at specific airports frequently prevent execution of an ideal descent at best economy speeds. In these cases, the pilot should adjust his descent point so that an idle power descent is accomplished.ENROUTE DESCENTDue to the low drag of the advanced technology wing, proper descent planning is necessary to arrive at the desired altitude at proper speed and configuration. The distance required for the descent is approximately three times the altitude loss for no-wind conditions.In addition, excess airspeed is slow to dissipate and generally requires a level flight segment.Use the speed as indicated on the descent page of the FMC. If the information is not available from the FMC, use .74M/250 for minimum fuel burn. Use [3,5] .70M/280/250 [7,8,9] .76/280/250 for turbulent air or ATC requirements.Sec. 3 Page 148 737 Flight ManualPlan the descent to arrive at traffic pattern altitude at flaps up maneuvering speed about:• 12 miles out when proceeding straight-in.• About 8 miles out when making an abeam approach.A good cross check is to be at 10,000 feet AFE, 35 miles from the airport, with a speed of 250 knots.B737 aircraft are equipped to record the uninterrupted audio signals received by a boom or a mask microphone. Flight crewmembers are required to use the boom microphone below 18,000 feet MSL.DESCENT IN MODERATE TO HEAVY PRECIPITATIONIf, at all possible, moderate or greater precipitation in the form of rain, hail, or sleet should be avoided. Advance planning and effective use of weather radar to detect areas of precipitation will usually provide alternative flight paths around hazardous weather conditions. If rain, hail, or sleet of moderate or greater intensity is encountered or anticipated, the engine ignition switches should be placed to the FLT position.SPEED BRAKES AND THRUST USAGEWhile using the speedbrake during descent, allow sufficient margin in altitude and/or airspeed so that a smooth level off can be accomplished while lowering speedbrake and adding thrust without causing passenger discomfort or overshooting the desired altitude. Lower the speedbrake before adding thrust.Thrust Indications During DescentIt should be noted that during high speed descents from altitude with idle thrust set, a variation in all engine parameters may occur due to engine efficiencies and tolerances. Differences as high as 15% N1 between left and right engines have been observed during initial descent. These variations tend to diminish as altitude and airspeed decrease, and should be minimal by 10,000 feet. This condition is within normal operating limits.