FMC Screws Up the Landing

[zubart 5]

737-700When using autothrottle, position MCP command speed to VREF +5. Sufficient wind gust protection is avaiable with autothrottle engaged because the autothrottle adjust athe approach speed upward to account for wind gust actually encountered during the approach.If the autothrottle is disengaged, or is planned to be disengaged proior to landing, the recommended method for approach speed correction is to add half of the reported steady wind to the reference speed. One half of the reported headwind component can be estimated by useing 50% for a direct headwind, 35% for a 45 degree crosswind, sero for a direct crosswind and interpolation in between.When making adjustments for wind additives, the maximum command speed set on the MCP should not exceed VREF +20 knots. The minimum approach speed set on the MCP should never be less than VREF +5 in any 737. However, there's one exception. VrefICE. VrefICE = VREF +10 VREF ICE is used for abnormal flap setting approaches, flaps 15 or less and when wing TAI has been used during the flight or engine TAI will be used on the approach. The reason is stick shaker logic and minimum manueuvering speed bars on the airspeed indications remain set for icing conditions once wing or engine TAI has been used or is being used. Therefore, manually input VrefICE into the FMC. Determine Vref +10 for approch flap setting. Imput this number on the approach ref page. This becomes your new Vref. (PMDG's FMC does not permit this)Now you can add any wind correction to this number using the same rule mentioned above. When VrefICE is required, the wind additive should not exceed 10 knots.

[Guest 737pilot]

Hello Tim,After reading your reply here about the definition of Vref, I finally got a better understanding of landing speed and flaps setting.I should add in that English is not my native language, and I still regard myself as quite a newbie when it comes to aviation.Today I finally succeeded in my first FMC autoland; it happened at Malaga airport in Spain (LEMG) on runway 32.I have attached a picture of the event.Kind regards,Nicohttp://forums.avsim.net/user_files/43114.jpg

[Guest amerton]

You mean this time the *FMC* did not *screw up* your landing ???Glad about it !anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com