It reduces the risk of accidents on flight (8)
I believe the answer is:
banister
This clue could be a double definition.
'it reduces' is the first definition.
The definition suggests a singular noun which matches the answer.
'risk of accidents on flight' is the second definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'the' is the link.
Can you help me to learn more?
(Other definitions for banister that I've seen before include "support at hand on flight" , "Stair handrail and supports" , "Rail beside a staircase" , "Support running alongside stairs" , "Stair-rail" .)