Iridium

In climbs, an airspeed hold should always be used rather than a vertical speed hold. The reason is that as you climb higher, the aircraft will need to pitch up more in order to maintain the desired vertical speed, which means you will bleed off airspeed and eventually stall. Above ≈FL290, you should be holding a constant mach rather than a constant IAS. The climb profile I use when I fly this plane in real life is as follows: (usually) 200KIAS to 2,500ft (above field elevation, or AFE). Then, provided there are no other departure speed restrictions, speed up to 250KIAS until 10,000ft MSL. Then transition to 270KIAS until IAS/Mach transition (usually ≈FL290), at which point I maintain 0.73M until cruise. At cruise, the airline I fly for wants us to maintain 0.75M, but the aircraft is usually capable of faster speeds (depending on weight and atmospheric conditions). In the descent, I like to maintain 0.75M until the Mach/IAS transition altitude, at which point we typically transition to 290KIAS (unless otherwise required by the descent or ATC). Flying into KPDX on the TMBRS.2 or KRATR.2 arrivals, we maintain 280KIAS until 10,000ft MSL, at which point we slow to 250KIAS until further slowed by the STAR (or ATC). Getting back to my original point, V/S for descent can be okay, but a speed hold (such as FLCH) is the only climb method that should ever be used. Momentary usage of V/S for short climb durations (to quickly expedite a climb) can be used, but you need to pay very close attention to your airspeed.