Assertion: boom | /r/CapableOf | keep airport noise
Facets:
value: to stage 4
type: TEMPORAL
Source sentences:
text: While other supersonic transport projects have traded cruise speed for lower noise, Boom wants to maintain a Mach 2.2 cruise to fit with transoceanic airline timetables and allow higher utilization, while keeping airport noise to Stage 4, similar to subsonic long range aircraft.