Hi,

Recently when I flew the 737, I got assigned a speed restriction, in mach, in this case, mach 0.76. So, I entered it into the CDU, on the CRZ page's Target Speed, for reference. Now, normally when I do this, especially for higher mach numbers, there's nothing special, and the Target Speed displays exactly what I entered.

However, in this particular case, when I entered, mach 0.76, the Target speed in the CDU showed "235/FLAPS". Also, it might be worth noting that later on, after about 10 minutes, the CDU displayed exactly what I'd put in, which was mach 0.76, so why didn't it do that straight away? So, my question is, what is the local behind this, and why did it convert my mach into KIAS during cruise? (I am aware that this will happen during descent when the mach number meets the speed, but why did it occur during cruise?) And also, based on this exact example, what does the "flaps" part mean in: "235/FLAPS"?

 

Thanks in advance!

I could be wrong, but doesn't that indicate that the 235 speed limit is based on flap setting? Did you inadvertently drop the flaps somehow?

That might indeed be fully correct.

However, as much as it is possible, I find it very unlikely, since I've never 'accidentially' extended the flaps before, and "235/FLAPS" was only displayed when I selected mach 0.76.