Creating an algorithm for hard landing detection using aircraft flight data
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2023
Författare
Gunnarsson, Jacob
Angervall, Fredrik
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Aircraft hard landings can cause damage to a landing gear or aircraft frame which
in turn can cause a critical failure. As such, methods to detect hard landings have
been created in different ways, for example, based on a pilot’s judgment or adding
various sensors to a landing gear.
The aim of the thesis is to identify existing hard landing detection methods and
compare them in order to find a suitable concept to further evaluate in regards to
application in a commercial aircraft. The literature review of current hard landing
detection methods and interviews with aerospace engineers showed that using flight
data parameters was a promising concept.
A load predicting algorithm was created and tested in order to evaluate the concept.
To make the algorithm, a CAD model of an arbitrary main landing gear (MLG) was
first built for implementation in a multi-body dynamic model. This was then used
to create a database of landing gear responses for different drop test simulations.
Through sweeps over relevant parameters, longitudinal and normal tire forces were
obtained for a spread of drop tests.
The database was then used in the algorithm, based on an interpolation scheme, to
give tire longitudinal and normal forces as an output at three critical instances. The
outputs could in the future be used to decide whether a hard landing has occurred
or not by comparing them to limits. It became evident that a good database is
necessary for the algorithm to provide proper force estimations.
The algorithm was accurate for an assumed runway friction. However, for a lower
friction, the estimated forces were inaccurate. An alternative method using the angular
velocity of the wheel to estimate the longitudinal force independent of friction
was tested. While simplifications were made, it was shown that the method gave
better estimations for low friction.
Using aircraft flight parameters for detecting hard landings was proved to be a
concept with potential. For implementation in commercial use however, several
points were identified as requirements for it to be a reliable method with high fidelity
and functionality.
Beskrivning
Ämne/nyckelord
Structural Health Monitoring , Hard Landing Detection , Drop Test Simulation , Aircraft Landing Gear