Adding a bit to what Tom has said... most current generation aircraft have a multiple air-to-ground capabilities for transmitting maintenance data. Most common is ACARS (Aircraft Communications Addressing and Reporting System), which is a customizable reporting mechanism. ACARS uses predefined triggers to send a given set of information to the ground. Usually, the trigger is some kind of fault or parametric exceedance. On Boeing aircraft (and I assume it is the same on Airbus), the airline can customize both the triggers and what is sent to ground in the report. To give you some idea of the scope of this system, the 787 has 146,000 different parameters on the databus, from which the airline could choose to be included in an ACARS report - the reports include everything from temperatures and pressures, to valve positions and aircraft as-flying configuration data. On some aircraft (for Boeing, it is the 747-400, 787 and 747-8i), engineering on the ground can send a request to the airplane for a customized report, thus triggering an on-demand report, rather than waiting for the predefined triggers on the airplane to send something. This can be particularly useful after the airplane has sent an automated ACARS report and engineering decides they want more data while the airplane is still flying.
There is a step beyond this, but it is not at all common.
ACARS is real-time monitoring, but it is not continuous. In other words, unless the airplane decides to send a report, the airline on the ground has not information on what the airplane is doing. For continuous monitoring (something some aircraft can support), the aircraft continuously streams data to the ground, in more of a telemetry system. Most operators do not use this, as it hogs a whole lot of bandwidth for limited operational value. Instead, virtually all aircraft have servers or memory modules to record this stream of data, storing it onboard until the aircraft gets back to earth. On the ground, appropriately equipped aircraft can use a gatelink (terminal-wireless / wifi) connection, to automatically send the captured data to airline engineering (or a 3rd party service) via the internet. For aircraft operating without gatelink capability, the stored data is typically retrieved at the airplane via physical retrieval of the memory module, or by taking a laptop to the airplane and pulling the data.
It may well be that LH
is actually doing real-time continuous monitoring. Of all operators out there, LH
has both the engineering sophistication to make this information operationally useful, as well as having aircraft which are equipped to support the practice (Most LH
long-haul aircraft have a satellite broadband connection),
Hope that helps!