  This paper reports on the integration of runtime monitoring into
fully-electric aircraft designed by Volocopter, a German aircraft manufacturer
of electric multi-rotor helicopters. The runtime monitor recognizes hazardous
situations and system faults. Since the correct operation of the monitor is
critical for the safety of the aircraft, the development of the monitor must
follow strict aeronautical standards. This includes the integration of the
monitor into different development environments, such as log-file analysis,
hardware/software-in-the-loop testing, and test flights. We have used the
stream-based monitoring framework RTLola to generate monitors for a range of
requirements. In this paper, we present representative monitoring
specifications and our lessons learned from integrating the generated monitors.
Our main finding is that the specification and the integration need to be
decoupled, because the specification remains stable throughout the development
process, whereas the different development stages require a separate
integration of the monitor into each environment. We achieve this decoupling
with a novel abstraction layer in the monitoring framework that adapts the
monitor to each environment without affecting the core component generated from
the specification. The decoupling of the integration has also allowed us to
react quickly to the frequent changes in the hardware and software environment
of the monitor due to the fast-paced development of the aircraft in a startup
company.
