737 Autothrottle disconnect procedure

[basa 0]

Good morning 737 crews !After 4 months flying the NG, reading the manuals and the available tutorials, I have two unsolved questions:1).- Which is the correct autothrottle disconnect procedure in a non-autoland precision approach ?I normally do this:At minimums I disengage the autopilot.At 50 ft I start the flare, disconnect AT and retard the throttles to idle.Is it correct ?And the second question:2).- What is FPV (flight path vector) indicator in the PFD used for ?I have read about it in the manuals and in Tim Metzinger's tutorials but I don't get to understand it.Thanks in advance. Jose Luis.

[downscc 1,327]

1) You're not wrong.. I will often cut A/P at 1000 agl just for the fun of flying. My technique for cutting A/T is to hit F1 just before flare.2) The FPV "points" in the direction that the aircraft is moving, which is not the same as your attitude (you can sink in a level attitude) or your heading (due to winds). The FPV is just another source of information in addition to wind correction angle, rate of descent, etc. They are a key indication on a heads up display, but I find the current presentation only useful as a secondary source of information.

[basa 0]

Thanks very much Dan.If I understand, hitting F1 you can get both AT disconnect and idle power at one time, isn't it?. That is very interesting !! I thought F1 was only used to "close" the reversers.The learning never ends...Jose Luis.

[zubart 5]

Question 1During a manual approach and landing, Boeing will preach that if the Autopilot is disengaged, then the autothrottle should be disengaged to avoid "confusion"??? Anyway, unless driven by their company's auto throttle SOP, in real practice, the majority of pilots will disengage the auto-throttle somewhere between 1000 feet and touchdown. During a manual landing, there is nothing published by Boeing to prohibit a touchdown with the auto-throttle engaged.Question 2The FPV displays Flight Path Angle relative to the horizon line and drift angle relative to the center of the pitch scale on the attitude display. This indication uses inertial and barometric altitude inputs. The vertical flight path angle displayed by the FPV should be considered unreliable with unreliable primary altitude displays. The FPV can be used by the pilot in several ways:- as a reference for establishing and maintaining level flight when the F/D is not in use or not available. When maneuvering the airplane,adjust pitch to place the FPV on the horizon. This results in zero vertical velocity.- as a cross check of the vertical flight path angle when established in a climb, descent or on a visual final approach segment. When on final approach, the FPV does not indicate airplane glide path relative to the runway. ILS glide slope, VASI/PAPI or other means must be used for a proper glide path indication.- in climbs or descents, radar tilt can be adjusted to an appropriate elevation based on the displayed FPV. Radar tilt, like the FPV, is reference to the horizon. Example: adjust the radar tilt to the same relative angle to the horizon as the FPV during climb results in the radar beam centered on the existing flight path.- as a qualitative indication of the airplanes lateral drift direction if the map is not available. The FPV moves left or right of the pitch scale to indicate the relative position of the ground track to the present heading. the amount of drift cannot be determined from this display unless the airplane is equipped with heading marks on the horizon line. Example: FPV displaced to the left indicates wind component from the right and corresponding drift to the left.- as a reference be the pilot in maintaining proper pitch control with unreliable airspeed indications. Adjust pitch to establish desired flight path by placing the FPV just above , below or on the horizon.Good luck,Floyd

[basa 0]

Floyd:Thanks very much for your valuable info.I can see that the Boeing A/T disconnect procedure is a very open issue.The boys at Airbus solved it time ago with the RETARD !! RETARD !! callout at 20 ft: then you bring the throttles back to the idle notch and A/T automatically disconnects.That makes the difference between B and A.Jose Luis.