CPL Helicopter cheat sheet

ICAO Annex 2 right-of-way: converging aircraft of the same category give way to the one on the right; a helicopter must give way to aeroplanes, gliders and balloons, and all aircraft give way to balloons.

Minimum VFR flight visibility and cloud distance depend on airspace class: in Class C/D/E at and above 3050 m (10 000 ft) AMSL, 8 km visibility and 1500 m horizontal/300 m vertical cloud separation apply (ICAO standard table).

Aircraft may not be flown closer than 150 m to any person, vessel, vehicle or structure except with the permission of the competent authority; congested-area minima are set by the State.

Simulated instrument flight requires a safety pilot able to see outside; a helicopter may not carry passengers under IMC unless the pilot holds a valid instrument rating.

Aircraft documents carried on board: certificate of registration, certificate of airworthiness, crew licences, journey log, and where required the radio station licence and noise certificate.

Fuel reserve for VFR flight by day: enough to reach the destination plus 30 minutes at cruising level (45 minutes by night or in IMC for helicopters under common State rules).

Aircraft must be operated within the certified limitations; flight manual limitations are legally binding and override company or pilot preference.

Pre-flight action: pilot-in-command must familiarise with all available information relevant to the intended flight, including weather, NOTAM, fuel and load, and alternate availability.

Logbook and duty-time records: flight time is recorded from the moment the helicopter first moves under its own power for the purpose of taking off until it comes to rest at the end of the flight.

Main rotor head types: fully articulated (flapping, lead-lag and feathering hinges), semi-rigid/teetering (two-blade, underslung flapping hinge), and rigid (bearings flex, no flapping hinge).

Fenestron and NOTAR systems produce anti-torque without an exposed tail rotor; NOTAR uses Coanda-effect circulation control rather than a fan in a duct.

Freewheel unit (sprag clutch) disconnects the engine from the rotor during autorotation, allowing the rotor to turn while the engine idles or fails.

Turboshaft engine limits are expressed as N1 (gas generator) and N2 (power turbine) percentages plus torque or MGT; exceedance of any one limit is an engine limit exceedance.

Hydraulic boost failure in most light helicopters leaves direct mechanical control with increased stick forces; the pilot must reduce speed and plan a shallow approach.

Rotor brake holds the rotor stationary on the ground; it must be released before starting and never applied with the rotor turning above the specified RPM.

Fuel system: sump drains are checked for water and sediment before the first flight of the day; a fuel shut-off valve and a fuel filter bypass warning are typical.

Electrical: a failed generator leaves battery-only operation, so non-essential consumers must be shed and landing planned before battery depletion.

Main rotor blade tracking and balance affect vibration; out-of-track blades cause 1-per-revolution vibration and must be corrected per maintenance data.

Density altitude = pressure altitude + 120 ft per 1 °C above ISA temperature; high density altitude reduces both engine power and rotor thrust.

Hover performance is limited by three ceilings: hover in ground effect (HIGE), hover out of ground effect (HOGE), and the OGE ceiling where climb performance reaches zero.

Weight and balance: the centre of gravity must remain inside the certified fore and aft limits for all loading states and fuel burn; lateral CG matters in helicopters with side-mounted tanks.

Autorotation performance: rate of descent is minimised at the speed for minimum descent, while glide range is maximised at a higher speed (approximately 60-70 KIAS in typical light types).

Take-off and landing performance must be computed for the most limiting condition: pressure altitude, temperature, wind, and slope or surface.

Fuel planning: trip fuel + reserve + contingency + taxi; verify the planned fuel does not exceed the usable capacity and that CG stays valid at zero fuel.

Headwind improves both hover ceiling and range; a tailwind during hover out of ground effect can push the helicopter above the HOGE ceiling.

Slope landings: land uphill/downhill per the flight manual, keep the rotor clear of the slope, and expect reduced tail clearance on downslope landings.

Performance class concepts (Category A/B): Category A procedures guarantee a defined climb gradient after engine failure; Category B accept a forced landing capability.

Hypoxia symptoms: euphoria, impaired judgement, cyanosis, headache and visual loss; time of useful consciousness at 25 000 ft is roughly 3-5 minutes without supplemental oxygen.

Spatial disorientation in helicopters includes somatogravic illusion during acceleration (feels like a climb) and the leans after a rolling manoeuvre; trust the instruments.

Vestibular system: semicircular canals sense angular acceleration, otolith organs sense linear acceleration and gravity; neither is reliable in sustained co-ordinated turns.

Visual illusions: black hole approach makes the pilot fly too low; white-out and brown-out remove external references and require instrument or go-around action.

Fatigue: acute fatigue degrades vigilance and reaction time; cumulative sleep debt requires recovery sleep, and duty limits are set to prevent it.

Carbon monoxide poisoning from exhaust leaks causes headache and confusion without warning; cabin heat must be shut off and ventilation opened if suspected.

Stress and arousal follow the inverted-U curve: moderate arousal optimises performance, while high stress narrows attention and increases error rates.

Decompression and trapped gas: barotrauma of ears and sinuses worsens with a cold; do not fly with an upper respiratory infection.

Crew resource management: assertiveness, situational awareness, briefing, and closed-loop communication reduce error chains; the pilot monitoring should speak up early.

ISA: sea level temperature 15 °C, pressure 1013.25 hPa, lapse rate 1.98 °C per 1000 ft up to 11 km (tropopause).

QNH set on the subscale gives altitude above mean sea level; QFE gives height above the reference point; QNE/standard 1013.25 is used above the transition level.

Wind shear on approach: a decreasing headwind or increasing tailwind causes airspeed loss and undershoot; add power and go around if it cannot be countered.

Mountain waves form with strong winds perpendicular to a ridge, producing severe turbulence, lenticular cloud and strong downdrafts on the lee side.

Thunderstorms: avoid by at least 10 nm (20 nm for severe cells); hail, microbursts and lightning are hazards even outside the visible cloud.

Icing: carburettor icing can occur between -7 °C and +21 °C with high humidity; airframe icing increases weight and destroys rotor efficiency.

Fog and mist: radiation fog forms on clear calm nights; advection fog forms when warm moist air moves over a cold surface and needs wind.

Density altitude effects: hot, high, humid conditions reduce performance; relative humidity above 50% further reduces engine power.

METAR/TAF decoding: wind direction in degrees true, speed in knots, gusts after G, visibility in metres, cloud base in feet AGL, QNH in hPa.

True airspeed increases about 2% per 1000 ft of altitude for a given indicated airspeed; groundspeed is TAS corrected for wind.

Wind triangle: heading = track ± drift angle; drift = (crosswind / TAS) × 60 degrees approximately.

1-in-60 rule: a 1 nm off-track error after 60 nm flown equals 1° of track error; correction to destination = (distance off / distance to go) × 60.

Helicopter navigation often uses map reading with 1:250 000 or 1:500 000 charts, plus GPS as primary or supplementary means depending on approval.

Magnetic variation east is subtracted from true to give magnetic; deviation is read from the compass correction card and applied to magnetic to give compass heading.

Dead reckoning: position derived from heading, airspeed, wind and time; must be updated by fixes at intervals, more frequently near controlled airspace.

GNSS integrity: RAIM prediction is required for approaches; loss of RAIM means the receiver cannot guarantee position accuracy.

Low-level navigation: obstacles, wires and masts are not always charted; use maximum elevation figures (MEF) and maintain a safe terrain clearance.

Time calculations: time = distance / groundspeed; fuel burn = rate × time, and the ETA must be revised after each fix.

Pre-flight briefing covers departure, en-route, destination, alternates, fuel, weather, NOTAM and emergency plan; a passenger briefing covers doors, belts, and no smoking.

Standard radio calls: taxi, line-up, take-off, downwind, final and vacating; read back clearances containing route, altitude or frequency.

Approach and landing decision: if unstable by a defined gate (height or speed), go around; a stabilised approach is required before landing.

Hover and taxi procedures: keep the disc clear of obstacles, watch tail rotor clearance, and use ground crew signals or marshalling when available.

Emergency brief: engine failure in hover, in forward flight, tail rotor failure, fire; the pilot must have a pre-rehearsed action sequence for each.

Fuel management: switch tanks per schedule, monitor consumption against plan, and land with the reserve intact; never plan to arrive on minimum fuel.

Passenger and load control: manifest, weight and balance, secure loose articles, and brief doors-off operations where approved.

Flight following and position reporting: maintain listening watch and report positions at compulsory reporting points; use the transponder per airspace requirements.

Post-flight: record defects in the technical log, refuel, secure the rotor, and report occurrences through the safety reporting system.

Lift = ½ ρ V² S CL; in a helicopter the rotor disc supplies lift, and induced velocity through the disc determines induced power.

Translational lift: above about 15-20 kt the rotor leaves its own downwash, increasing efficiency and reducing power required.

Dissymmetry of lift in forward flight is balanced by blade flapping and cyclic feathering; retreating blade stall occurs at high speed or high load factor.

Autorotation: rotor driven by upward airflow; the driving region (inboard) drives the driven region (outboard), with the reverse-flow region near the hub.

Ground effect: reduced induced velocity near the surface increases thrust for a given power, effective up to about one rotor diameter.

Torque reaction: main rotor torque is opposed by the tail rotor; loss of tail rotor authority causes yaw, and the correct response is to reduce collective and enter autorotation.

Settling with power (vortex ring state): descent rate above 300 ft/min with low airspeed and high power; recover by increasing forward speed or reducing collective.

Transverse flow effect: in forward flight, the rear of the disc has a greater induced angle, producing a roll; it is corrected by cyclic input.

Blade coning increases with lift; coning reduces effective disc diameter and increases blade bending loads.

Distress call: MAYDAY MAYDAY MAYDAY, station addressed, callsign, nature of distress, position, altitude, intentions; distress has absolute priority over all other traffic.

Urgency call: PAN PAN PAN PAN PAN PAN, followed by callsign and nature of urgency; used when safety is not immediately threatened.

Read-back requirements: clearances, runway-in-use, hold-short instructions, altimeter settings and frequencies must be read back.

Phonetic alphabet and number pronunciation: figures are spoken digit by digit, with 3 as TREE, 5 as FIFE, 9 as NINER, and decimal as DECIMAL.

Position report format: callsign, position, time, altitude, next position and ETA; use standard phraseology and keep transmissions brief.

Loss of communication: squawk 7600, continue per the last clearance, and follow the published lost-communication procedure for the airspace.

Transponder codes: 7500 unlawful interference, 7600 radio failure, 7700 general emergency; Mode C gives pressure altitude.

Frequency change: confirm the new frequency, change, and re-establish contact; if no contact, return to the previous frequency before trying alternatives.

Emergency frequency 121.5 MHz is monitored for distress; ELT transmissions are detected there and should be reported to ATC.

Engine failure in hover: lower collective immediately, cushion the landing with collective at the bottom, and keep the rotor RPM in the green.

Engine failure in forward flight: lower collective to maintain rotor RPM, establish autorotation speed, select a landing area, and make the MAYDAY call if time permits.

Tail rotor failure: reduce collective, maintain forward speed above translational lift, and make a running landing; loss of the tail rotor in hover requires immediate landing.

Vortex ring state recovery: reduce collective, increase forward speed or enter autorotation to break the descent.

Dynamic rollover: occurs when a skid or wheel is caught and the helicopter pivots about the contact point; prevent by smooth collective and prompt correction of any roll.

Ground resonance: rotor imbalance and oleo/landing-gear interaction cause destructive oscillation; lift off immediately if it starts on the ground.

Fire in flight: close the fuel shut-off, isolate electrical power, land as soon as possible, and evacuate passengers upwind.

Autorotation landing: flare at about 50-75 ft, level, and cushion with collective; the touchdown must be judged with the collective still available.

Emergency float operations: water landing requires the floats armed, doors open, and a controlled ditching with the rotor stopped before evacuation.

ICAO Annex 2 right-of-way: converging aircraft of the same category give way to the one on the right; a helicopter must give way to aeroplanes, gliders and balloons, and all aircraft give way to balloons.

Minimum VFR flight visibility and cloud distance depend on airspace class: in Class C/D/E at and above 3050 m (10 000 ft) AMSL, 8 km visibility and 1500 m horizontal/300 m vertical cloud separation apply (ICAO standard table).

Aircraft may not be flown closer than 150 m to any person, vessel, vehicle or structure except with the permission of the competent authority; congested-area minima are set by the State.

Simulated instrument flight requires a safety pilot able to see outside; a helicopter may not carry passengers under IMC unless the pilot holds a valid instrument rating.

Aircraft documents carried on board: certificate of registration, certificate of airworthiness, crew licences, journey log, and where required the radio station licence and noise certificate.

Fuel reserve for VFR flight by day: enough to reach the destination plus 30 minutes at cruising level (45 minutes by night or in IMC for helicopters under common State rules).

Aircraft must be operated within the certified limitations; flight manual limitations are legally binding and override company or pilot preference.

Pre-flight action: pilot-in-command must familiarise with all available information relevant to the intended flight, including weather, NOTAM, fuel and load, and alternate availability.

Logbook and duty-time records: flight time is recorded from the moment the helicopter first moves under its own power for the purpose of taking off until it comes to rest at the end of the flight.