pilot can set this white bug at any value more than 60 knots. It shows on the speed tape and the numeric value shows on the bottom right of the speed tape.
The NO VSPD message shows when V1 or VR is not valid or the performance initialization has not been entered in the flight management computer system. The NO VSPD message is displayed in amber.
Landing Reference Speeds
The landing reference speed bugs are VREF (reference landing speed) and VREF+15.
With the speed reference knob in the AUTO position, VREF is calculated by the FMCS and sent to the CDS for display. The VREF tick mark and readout are displayed in green.
Alternatively, VREF can be set manually via the speed reference knob on the engine control display panel. The VREF tick mark and readout is displayed in green.
The DEU then calculates VREF+15 and shows it on the speed tape. VREF +15 is displayed as a white bug.
Limit Speeds
Maximum operating speed shows the lesser of the VMO/MMO, landing gear or trailing edge flap placard speeds as a red and black barber pole (alternate squares) at the top of the speed tape. The maximum speed display will show from the actual maximum speed
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CDS -- PFD - AIRSPEED INDICATIONS
value to the top of the speed tape. Maximum operating speeds are calculated in the SMYDs using Mach number, altitude, VMO/MMO, flap position and landing gear position.
Maximum maneuver speed shows the highest speed before the onset of high speed buffet. It is a hollow amber bar. It originates at the maximum maneuver speed and extends up to the maximum operating speed barber pole. Maximum maneuver speed data is calculated by the FMCS using airplane gross weight, altitude, center of gravity and approved G margin and sent to the DEUs via the SMYDs.
Minimum operating speed (also known as Stick Shaker speed) shows the speed at which the stick shakers will operate. It shows as a red and black barber pole (alternate squares) at the botttom of the speed tape. The minimum speed display will show from the actual minimum speed to the bottom of the tape. Minimum operating speed is calculated in the SMYDs using airspeed, angle of attack data, flap position and Mach number. It is not displayed on the ground.
Minimum maneuver speed shows the lowest speed before the onset of low speed buffet. It is a hollow amber bar. It originates at the actual minimum maneuver speed and extends down to the minimum operating speed barber pole. Minimum maneuver speed data is calculated by the FMCS using airplane gross weight, altitude, center of gravity and approved G margin and sent to the DEUs via the SMYDs. it is not displayed on the ground.
737-600/700/800/900 TRAINING MANUAL
Flap Maneuver Speeds
Flap maneuver speed bugs for flap retraction or extension show as tick marks with the flap setting on the speed tape.
The speed bugs show for flap positions UP, 1, 2, 5, 10, 15 and 25 units. There are no flap speed bugs for flap positions 30 and 40 units. CDS uses FMCS gross weight and flap lever position from the flap slat electronic unit (FSEU) to calculate flap maneuver speeds. Flap maneuver speed bugs and readouts are displayed in green.
Alternatively, airplane weight can be entered manually on the engine display control panel and this weight will be used by CDS to calculate flap maneuver speeds. The weight shows in pounds adjacent to the speed tape and is displayed in green.
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737-600/700/800/900 TRAINING MANUAL
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SELECTED
SELECTED SPEED
MACH NUMBER MANUALLY
V2+15 SELECTED SPEED
SET BUG SELECTED
BUG (OFFSCALE) SPEED BUG
FLAP MAXIMUM MANEUVER
REFERENCE TAKEOFF
SPEED SPEEDS MAXIMUM
SPEED VREF+15
SPEED MANEUVERTREND LANDINGSPEEDVECTOR
REFERENCE SPEEDCURRENT AIRSPEED AIRSPEED
MINIMUM DISAGREE
MANEUVERREMINDER BUG MESSAGE
SPEED MANUAL
MINIMUMAIRSPEEDS SPEED
MACH NUMBER
OR WEIGHT
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