Aircraft Dispatcher cheat sheet

Radar separation minima are 3 NM within terminal areas and 5 NM en route; both require 1,000 ft vertical separation when applied concurrently.

Standard vertical separation is 1,000 ft below FL290; 2,000 ft is required above FL290 in non-RVSM airspace, while RVSM permits 1,000 ft between FL290 and FL410.

Transponder codes: 7500 unlawful interference, 7600 radio communication failure, 7700 general emergency; ATC assigns and confirms the code on initial contact.

ILS categories: CAT I decision height 200 ft and RVR 1,800 ft (550 m); CAT II DH 100 ft and RVR 1,200 ft; CAT IIIa RVR below 700 ft.

TAS = Mach × local speed of sound; LSS is about 661 kt at MSL ISA and about 573 kt in the lower stratosphere, so a given Mach yields higher TAS with altitude.

ADF: magnetic bearing to station = relative bearing + magnetic heading; with no wind, the heading to the station equals that bearing plus or minus 180 degrees.

Below the transition altitude the altimeter is set to QNH to indicate altitude; at and above the transition level it is set to 1013.25 hPa (29.92 inHg) and flight levels are flown.

1 NM = 6,076.12 ft; 1 knot = 1 NM per hour; 1 degree of latitude = 60 NM.

ISA at mean sea level is 15 °C and 1013.25 hPa, with a lapse rate of about 2 °C per 1,000 ft up to the tropopause near 36,090 ft and −56.5 °C.

Ceiling is the height of the lowest broken or overcast layer, or the vertical visibility into an obscuration; scattered layers do not constitute a ceiling.

Radiation fog requires clear skies, light wind, and a small temperature-dew point spread; advection fog forms when warm moist air moves over a colder surface.

Thunderstorm life cycle: cumulus stage (updrafts), mature stage (both updrafts and downdrafts, hail, lightning, worst turbulence), dissipating stage (downdrafts).

Freezing rain and freezing drizzle are classified as severe icing because supercooled large drops can accumulate faster than deicing and anti-icing systems can cope.

Standard holding pattern: right turns, 1-minute inbound legs at or below 14,000 ft MSL and 1.5-minute legs above; entries are direct, parallel, or teardrop.

Wind shear on approach is handled by going around with maximum thrust and a maintained pitch attitude rather than chasing the glide slope.

Jet streams are concentrated near the 200-300 hPa level, typically 30,000-40,000 ft, with core speeds of at least 50 kt and often above 100 kt.

Key speeds: V1 decision speed, VR rotation speed, V2 takeoff safety speed (minimum climb speed with one engine inoperative), and VREF = 1.3 VSO.

Balanced field length is the runway length at which accelerate-stop distance equals accelerate-go distance, and it defines the field-length-limited V1.

Density altitude ≈ pressure altitude + 120 × (OAT − ISA temperature); rising density altitude raises TAS for a given IAS, lengthens the takeoff roll, and reduces climb gradient.

Percent climb gradient = (altitude gained ÷ horizontal distance travelled) × 100; a 3.3 percent gradient equals about 200 ft per nautical mile.

For transport-category jets the required dry landing distance is the actual demonstrated distance divided by 0.6, equivalent to multiplying by 1.67.

A headwind improves climb gradient and shortens ground roll, while a tailwind degrades both and can sharply increase takeoff distance.

Contaminated runways reduce braking friction, so dispatch must use contaminated-runway performance data rather than dry-runway figures.

Turbine thrust is flat-rated up to a break temperature and then decreases as temperature or altitude increases; high-altitude airports therefore reduce available thrust.

CG = total moment ÷ total weight, where each moment is the item weight multiplied by its arm measured from the datum.

Weight shift: distance the CG moves = (weight shifted × distance between stations) ÷ total weight; shifting weight aft moves the CG aft.

Maximum zero fuel weight is the maximum weight without usable fuel and is a structural limit protecting wing bending; it is normally below maximum takeoff weight.

Maximum landing weight limits landing; maximum takeoff weight may be further limited by field length, climb, obstacle clearance, tire speed, and brake energy.

Percent MAC = (CG arm − LEMAC arm) ÷ MAC length × 100, expressing CG position along the mean aerodynamic chord.

Operating empty weight includes crew, crew baggage, potable water, engine oil, and unusable fuel but excludes payload and usable fuel.

Adding weight ahead of the CG moves the CG forward, raising stall speed and increasing elevator authority needed for rotation.

An aft CG reduces trim drag but also reduces longitudinal static stability; loading beyond the aft limit can cause pitch control problems.

Fuel plan components: taxi fuel + trip fuel + contingency fuel + alternate fuel + final reserve fuel + additional fuel.

1-2-3 rule: an alternate is required when the destination forecast for ETA ±1 hour shows a ceiling below 2,000 ft or visibility below 3 statute miles.

Alternate minimums: for a precision approach add 200 ft to DA/DH and 1/2 SM visibility; for a non-precision approach add 400 ft and 1 SM.

Equal time point distance = (total route distance × return groundspeed) ÷ (outbound groundspeed + return groundspeed).

Wind correction angle ≈ arcsin[(wind speed ÷ TAS) × sin(wind angle)]; true heading = true course + WCA, and magnetic heading applies variation (subtract easterly).

1 degree of latitude equals 60 NM, so a great circle distance can be estimated directly from latitude difference along a meridian.

A rhumb line holds a constant true track on a Mercator chart, while a great circle is shorter but requires continuously changing headings.

Cruise TAS increases with altitude up to the tropopause and then stays roughly constant, while fuel flow typically decreases with altitude.

Final reserve fuel is 30 minutes of holding at 1,500 ft above the alternate at holding speed for turbine aircraft, and 45 minutes for piston aircraft.

Contingency fuel is normally 5 percent of trip fuel, or 3 percent when a suitable enroute alternate is available.

Minimum fuel is declared when the flight is committed to land at a specific airport and any change to the clearance would result in landing below final reserve.

Emergency fuel is declared when fuel is expected to be below final reserve; ATC then treats the flight as an emergency and gives priority handling.

Fuel dumping is normally conducted after ATC coordination and at least 2,000 ft above the surface, avoiding populated areas and other aircraft.

The dispatcher and the pilot in command share operational control; the dispatcher monitors fuel, weather and alternates and issues a new release when conditions change.

Tankering uplifts extra fuel at a cheaper station when the price difference exceeds the cost of carrying the additional weight.

On long high-altitude flights, cold-soaked fuel can approach its freeze point, so fuel freeze point is checked against expected tank temperature.

A dispatcher certificate requires the applicant to be at least 23 years old, read, speak and understand English, pass the knowledge, oral and practical tests, and meet the experience or training requirement.

A certificated dispatcher may not remain on duty more than 10 hours in any 24-hour period and must receive 8 consecutive hours of rest in the preceding 24 hours.

The dispatch release must show flight number, aircraft, route, minimum fuel, alternates and weather, and must be signed by both the dispatcher and the pilot in command.

The pilot in command may deviate from any rule in an emergency to the extent required, and the dispatcher cannot override that emergency authority.

Domestic Part 121 alternate requirements follow the 1-2-3 rule; flag operations carry additional destination and enroute alternate requirements.

Twin-engine operations beyond 60 minutes from an adequate airport require ETOPS approval, with the time limit set by type design and the operator's authorization.

Crew members may not act within 8 hours of consuming alcohol, while under the influence, or with a blood alcohol concentration of 0.04 percent or greater.

The minimum equipment list permits operation with specified inoperative items under stated conditions; airworthiness directives must be complied with before flight.

The dispatcher must record and retain flight watch and release documentation as required by the operator's manual and Part 121.

Squawk 7700 for a general emergency, 7600 for radio failure, and 7500 for unlawful interference.

After a rapid decompression at FL350, useful consciousness is typically 30-60 seconds, so oxygen masks are donned before initiating the descent.

Emergency descent targets FL100 or the minimum safe altitude, whichever is higher, at the maximum practicable rate with the transponder on 7700.

Below V1 an engine failure calls for rejecting the takeoff; above V1 the takeoff is continued, the aircraft cleaned up, and the engine handled after climb is established.

Smoke or fire: identify the source, isolate electrical power to the affected system, use the appropriate extinguisher, and plan an immediate diversion.

Time of useful consciousness is roughly 3-5 minutes at FL250, 30-60 seconds at FL350, and 15-20 seconds at FL400.

Fatigue-related errors peak during the circadian low around 0300-0500 local time, when alertness and situational awareness are lowest.

Overweight landing is permitted in an emergency; consider fuel dumping to reach maximum landing weight, but land immediately if the situation is deteriorating, then accomplish the overweight landing inspection.

CRM involves briefing the approach, allocating tasks, calling out deviations, and using all resources including ATC, dispatch, and cabin crew.