Originally Posted by
RAT 5
If you do this manoeuvre during SID, e.g. 6000' level flight on a busy TMA, you are heading for trouble. ATC want you in level flight. You set these parameters and climb and accelerate. While attempting to follow the check list you get an RA. ATC is shouting at you to maintain 6000' due traffic.
RAT5, remember the reason of the unreliable airspeed could also have an effect on incorrect altimeter readings, including those providing input to transponder for altitude alerting. Thus you may think you are in level flight, or indeed ATC might, when in fact you are not. TCAS is only as good as its inputs, which in this case can be wrong. The list of items which may be unreliable are included at the bottom of the 737NG checklist by Boeing, as is the list which is relievable.
The following are reliable:
•Attitude
•N1
•Ground speed
•Radio altitude
One or more of the following may be evidence of unreliable airspeed or Mach indications:
•Speed/altitude information not consistent with pitch attitude and thrust setting
•SPD failure flag
•SPD LIM failure flag
•IAS DISAGREE alert
•Blank or fluctuating airspeed display
•Variation between captain and first officer airspeed displays
•Radome damage or loss
•Overspeed warning
•Simultaneous overspeed and stall warnings.
Until you identify failure (possibly after running the checklist) you cannot guarantee that any RA is valid either as the selected altitude information (item 1 on above list) may not be accurate.