# Why is my plane's nose shaking up and down erratically?

Over the history of this forum that I have partaken in, a lot of topics have popped up about why the nose is violently swinging uo and down. Usually (If not always), here is the answer:

You’re flying too fast.

You ahould be cruising, depending on the aircraft at Mach 0.70 to Mach 0.87. To determine your Mach speed, look right below thr Airspeed gauge in the HUD. You’ll see another number like “GS ## kts.” That is the Ground Speed. Then look below that. That is your mach speed. When climbing above 10k ft. (The end of the speed restriction), I watch that gauge while I’m climbing to make sure I don’t overshoot a readonable Mach level (You shouldn’t be climbing at Mach 0.70 though…). Watch it very closely when you finally level out in cruise because that is when your Mach speed really jumps up.

Cruising Speed:

You generally shouldn’t be cruising above M 0.87. For a 737, try and fly M 0.70 (This is a slow speed by the way) to M 0.78/79. For larger widebodies like the 747 or A380, try M 0.78 to M 0.87

For the record, the “M” stands for Mach and the “0.78” stands for the % of the speed of sound.

Hope this clears up confusion/helps!

Mods please delete or merge if this is a duplicate tutorial. Not sure what search terms I should use so I am relying on the ones with good memories or the other OPs about this tutorial.

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No need for me to mention VMO or MMO. Well, I could have but it would have been unnecessary details. To keep things simple for everyone, I would just say you can’t fly the plane faster than Mach 0.__. I don’t know nor am I intent on researchig the details of what the AS is while cruising at Mach 0.75 at 28k ft. is for example.

You shouldn’t fly too fast or too slow at high altitudes unless you wish to stall or break up. Should be detailed in the recommended cruising speed

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On an autopilot approach at 125 knots with almost no winds,my A320’s nose was shaking. When it touched down, it bounced and the nose landing gear went below the ground the next time it came down.

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Okay thanks

Also add about 20-30% nose up trim and apply back pressure, some one told me this on IFFG

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A little late on this post but normally for a 737 the crusing speed is .79 mach, .70 would be a stall speed depending on your altitude