How do airlines know exactly what you're doing on a/c

[z.khalid]

Just curious.
When hard landings, or if you do something funny you're not supposed to do, how do they know exactly?

Just curious. Thanks guys!

[SloppyJoe]

In modern airliners the aircraft tells them. Where I work the aircraft have set values that if exceeded a report is sent to the monitoring department. Things like +1,200ft/min below 1500ft, above VMO/MMO, above max alt, EGPWS warning and many many others. With a hard landing you know pretty soon after touch down as the ACARS prints out a hard landing report with the G on landing so that maintenance can start doing what they need to to clear it for the next sector.

Most professional pilots however will report any excursion beyond normal even if the aircraft does not.

[redsnail]

Depending on the company and the aircraft, e.g., mine doesn't at the moment but the fleet is being fitted with what we call "Flight Data Monitoring". It works along the lines of the Flight Data Recorder however, unlike the FDR, the FDM data can be routinely accessed.
Ours records onto a SD card which the engineers remove and replace. The data is read and sent to the FDM team within the Safety department.
One of our aircraft trialled a rather smart bit of kit. Instead of waiting to be downloaded, if a hard parameter was exceeded, it would send the message immediately. It had Wifi and 3G capability but if airborne, it would use the sat phone system to send the message.