We operate our utility 407's at altitudes of 6000 to 12000 ft with no problems. I've set 2,000 lb sling loads HOGE at 8,000' +10c. I've moved 1,800 lb+ snow guns at up to 9,000 ft with 400 lb of fuel (-5c). . .We routinely fly full seats/full gear plus a huge ski basket (all summer) with 600-700 lbs fuel, keeping vertical performance. It may not keep up to a B3, I don't know...never had the opportunity to fly one or even see a performance chart, but our 407 will out do any B2 that I've flown, and will certainly perform to the Bell performance specs in the Flight Manual.