THE AIRLINE PILOTS FORUM & RESOURCE

B737 Landing Vref Speed

by K.Haroon: Last Updated on 10th February 2007

Normal Conditions:

When using the autothrottle, position command speed to VREF + 5 knots.

If the autothrottle is disengaged or is planned to be disengaged prior to landing, the recommended method of approach speed correction is to add one half of the reported steady headwind component plus the full gust increment above the steady wind to the reference speed. One half of the reported steady headwind component can be estimated by using 50% for a direct headwind, 35% for a 45-degree crosswind, zero for a direct crosswind and interpolation in between.

When making adjustments for wind additives, the maximum command speed should not exceed VREF + 20 knots or landing flap placard speed minus 5 knots, whichever is lower.

Following are some examples of wind additives with a runway heading of 360.

Reported Winds	Wind Additive	Approach Speed
360 at 16	8	VREF + 8 knots
Calm	0	VREF + 5 knots
360 at 20 Gust 30	10 +10	VREF + 20 knots *
060 at 24	6	VREF + 6 knots
090 at 15	0	VREF + 5 knots
090 at 15 Gust 25	0 + 10	VREF + 10 knots

* If VREF + 20 exceeds landing flap placard speed minus 5 knots, use landing flap placard speed minus 5 knots.

Minimum command speed setting with autothrottle disconnected is VREF + 5 knots. The gust correction should be maintained to touchdown while the steady headwind correction should be bled off as the airplane approaches touchdown.

Do not apply wind corrections for tailwinds. Set command speed at VREF + 5 knots (autothrottle engaged or disengaged).

Non-Normal Conditions:

When VREF has been adjusted by the non-normal procedure, the new VREF is called the adjusted VREF and becomes the new VREF for landing. For example, if a non-normal checklist specifies "Use flaps 15 and VREF 15 + 10 for landing", the flight crew would select flaps 15 as the landing flaps and look up the VREF 15 speed (in FMC or QRH) and add 10 knots to that speed.

Adjusted VREF does not include wind corrections. If autothrottle is disengaged, or is planned to be disengaged prior to landing, appropriate wind corrections must be added to the adjusted VREF to arrive at command speed, the speed used to fly the approach. For example if the checklist states "use VREF 40 + 30 knots", command speed should be positioned to adjusted VREF (VREF 40 + 30) + Wind Correction (5 knots minimum, 20 knots maximum).

Disclaimer: "Selection of Command Speed in Landing B737-300" are personal notes of the author. These notes do not sanction any pilot to violate his Company's Standard Operating Procedures, Aircraft Manuals or Manufacturer's Recommendations.