Tee Emm
18th Mar 2014, 07:04
Recently I saw an old (1982) B737-200 FCTM and was reading advice on page 04.70.02 on Standard Callouts. It said "The pilot not flying will utilize the standard callouts, including any significant deviation especially when less than 500 feet above field elevation. Call out significant deviations from programmed airspeed, descent rate, and instrument indications:
Airspeed below V Ref or 10 knots above intended approach speed. If rate of descent exceeds 800 FPM. Localiser displaced more than 1/3 dot. Glideslope displacement greater than one dot"
I might add there was far more general handling information in those old FCTM's than current FCTM publications
Most will agree that excessive airspeed over the threshold, where runway length and surface conditions are marginal, are a primary cause of over-runs on landing. Company policies vary with regard to the calling of outside airspeed tolerances by the PF but a typical call would be initiated if the airspeed on short final was more than 20 knots above Vref or less than Vref. Boeing state that Vref plus 20 knots is maximum for landing. As the Boeing FTCM states above, a callout is required if airspeed is above the intended approach speed plus 10 knots. However the intended approach speed (Vref plus additives) could be as much as 20 knots above VRef. Therefore, just two knots above Vref+20 could trigger a typical call by the PNF of "Bug plus 2 knots" which doesn't arouse alarm.
However, a support call of Vref + 22 knots, is far more likely to get the pilot's attention than a call of Bug +2. Perhaps the risk of over-runs due to excessive speed may be reduced if support calls were referenced to the actual Vref speed rather than as present, referenced to the selected approach speed?
In all the cases described above, it is assumed use of manual throttle and not autothrottle where it is common to set Vref+ 5 as the approach speed. Comments appreciated.
Airspeed below V Ref or 10 knots above intended approach speed. If rate of descent exceeds 800 FPM. Localiser displaced more than 1/3 dot. Glideslope displacement greater than one dot"
I might add there was far more general handling information in those old FCTM's than current FCTM publications
Most will agree that excessive airspeed over the threshold, where runway length and surface conditions are marginal, are a primary cause of over-runs on landing. Company policies vary with regard to the calling of outside airspeed tolerances by the PF but a typical call would be initiated if the airspeed on short final was more than 20 knots above Vref or less than Vref. Boeing state that Vref plus 20 knots is maximum for landing. As the Boeing FTCM states above, a callout is required if airspeed is above the intended approach speed plus 10 knots. However the intended approach speed (Vref plus additives) could be as much as 20 knots above VRef. Therefore, just two knots above Vref+20 could trigger a typical call by the PNF of "Bug plus 2 knots" which doesn't arouse alarm.
However, a support call of Vref + 22 knots, is far more likely to get the pilot's attention than a call of Bug +2. Perhaps the risk of over-runs due to excessive speed may be reduced if support calls were referenced to the actual Vref speed rather than as present, referenced to the selected approach speed?
In all the cases described above, it is assumed use of manual throttle and not autothrottle where it is common to set Vref+ 5 as the approach speed. Comments appreciated.