Topics

Semi-rigid (teetering): two blades fixed to a hub that teeter as a unit — they can flap and feather but cannot lead/lag. Used on the R22 and R44. Simpler and lighter, but more susceptible to mast-bumping during low-G maneuvers. Fully articulated: each blade flaps, leads/lags, and feathers independently via separate hinges. Used on three- and four-blade systems (Bell 206, R44 four-blade, etc.). More complex and heavier, but absorbs vibration better and can suffer ground resonance — semi-rigid systems cannot.

US helicopters typically have a counter-clockwise (CCW) main rotor when viewed from above. Adding power applies more torque to the main rotor, which tries to rotate the fuselage in the opposite direction (clockwise, or nose-right) by Newton's third law. The tail rotor produces leftward thrust to counteract this — adding power means more torque means more tail rotor thrust required, which is right pedal input.

DA (Decision Altitude) is used on precision approaches — momentary descent below DA is acceptable during the missed approach if the visual references aren't established. MDA (Minimum Descent Altitude) is used on non-precision approaches and is a hard floor: you cannot descend below MDA without the required visibility and runway environment in sight. In short: DA is a decision point, MDA is a hard limit.

Only with SFAR 73 endorsements. A standard PPL Helicopter certificate authorizes most helicopters under 12,500 lbs — but the R22 and R44 are governed by SFAR No. 73, which requires specific training and an awareness endorsement before acting as PIC. With less than 200 hours of helicopter PIC, the SFAR also requires a recurrent flight review every 12 calendar months in the same model.

Two big ones. (1) 14 CFR 91.155: in Class G below 1,200 AGL, helicopters may operate clear of clouds at a speed allowing the pilot to see and avoid traffic — minimum visibility is 1/2 SM day, 1 SM night (vs. 1 SM clear of clouds for fixed-wing day). (2) 14 CFR 91.157 (Special VFR): helicopters can operate SVFR with no minimum visibility requirement, while fixed-wing requires 1 SM. (3) For IFR approaches, AIM 10-1-2 lets helicopters reduce the published Cat A visibility to half (or 1/4 SM / 1,200 RVR, whichever is greater).

They do — when the chart depicts one and SHARPTT doesn't apply, the same rules apply. But the helicopter community uses approaches more frequently with radar vectors or copter-specific approach plates that often eliminate procedure turns entirely. The 45/180, 80/260, and teardrop are the same; the difference is mostly in how often you actually fly one in operational helicopter IFR.

It's the autorotation technique used in IMC or at night when you can't see the ground in time to time the flare. Set a slightly lower-than-normal airspeed (~35–40 KIAS plus half the windspeed) and maintain that attitude all the way down — feed in collective slowly when the ground starts to make itself known, and accept the slight forward speed at touchdown. Do not flare — there isn't enough kinetic energy at the lower airspeed to change the flight path.

Carburetor heat introduces hot air, which is less dense than cold air. The carb cannot meter the same air mass at the same throttle position — effectively, the mixture richens and the engine produces slightly less power. The RPM drop is also a quick check that the carb heat is functioning; if the RPM doesn't drop, the carb heat may not be plumbed correctly. In a piston helicopter with a correlator/governor, the system compensates and the drop is small or absent.