Aircraft Dispatcher common mistakes
Aircraft Dispatcher · Understand the traps and how to avoid them.
Converting fuel gallons to pounds with a memorized 6.7 lb/gal (or 6.0 lb/gal) factor regardless of the density or temperature stated in the problem, and then carrying that wrong fuel weight into the zero-fuel-weight and ramp-weight totals.
The factor is one of the first numbers learned, so candidates apply it automatically and never re-derive it from the specific gravity the question provides; the resulting weight error is small enough to look plausible and never gets caught.
What to do instead
Always write the conversion as pounds = gallons x (stated density x 8.345) and show the arithmetic. Cross-check by verifying that the itemized weights sum to the total weight and that total moment divided by total weight reproduces the published empty-weight arm.
Entering a takeoff or landing distance chart with field elevation instead of pressure altitude, then applying the wind and slope corrections in an arbitrary order or skipping one because the numbers already 'looked good'.
Elevation is printed on the airport page in big type while pressure altitude must be computed from the altimeter setting; under time pressure the visible number wins. Correction order feels interchangeable because each correction is a separate row on the chart.
What to do instead
Convert first: pressure altitude = elevation + (29.92 - altimeter setting) x 1000, and hold it in a column next to the temperature. Then apply corrections in exactly the order the chart footnote specifies, writing each intermediate value before moving to the next line.
Reading a TAF or METAR and treating a TEMPO, BECMG, or PROB30 group as the prevailing condition for the whole period, or reading the valid period as local time and arriving at the wrong ETA window.
The report is a dense block of text and the forecast change groups look like ordinary condition groups; local-time reasoning is habitual outside aviation.
What to do instead
Annotate the raw text before answering: box the prevailing group, underline change groups and write 'temporary' or 'becoming' beside them, and write the validity window in Zulu on both ends. Only a condition that persists at the ETA itself governs alternate selection.
Treating any reported layer as a ceiling and comparing visibility given in meters directly against a statute-mile minimum without converting.
The word 'ceiling' is used loosely in everyday speech, and metric visibilities are common in international reports, so the units mismatch is invisible unless it is deliberately checked.
What to do instead
State the rule before computing: ceiling is the lowest broken or overcast layer, or vertical visibility into an obscuration; scattered layers are not ceilings. Convert meters to statute miles by dividing by 1609 (or use the 1600 m = 1 sm approximation only to check the order of magnitude).
Applying the 1-2-3 alternate rule by looking only at the forecast at the exact ETA, and failing to add or subtract the one-hour window on either side before deciding an alternate is required.
The rule is remembered as three numbers rather than as a rule about a time window, so candidates evaluate a single column of the forecast.
What to do instead
Before answering, draw the window: ETA minus one hour to ETA plus one hour, and require an alternate if any forecast condition inside that window falls below a 2000-foot ceiling or 3 statute miles visibility. Write the window on the scratch sheet, not mentally.
Building the fuel plan without the 45-minute reserve, or computing the reserve at holding burn rate instead of normal cruise, and omitting taxi, APU, and engine-start fuel from the ramp fuel figure.
The reserve gets confused with the holding segment of the alternate calculation, and taxi/APU fuel is treated as trivia rather than as part of the total.
What to do instead
Lay the plan out as a vertical ladder - taxi, trip, contingency, alternate, reserve - with a burn rate and a time beside every line, and confirm the reserve line reads '45 minutes at normal cruise power.' Sum the ladder twice: once for landing fuel and once for required ramp fuel.
Applying the east-is-least/west-is-best variation rule in the wrong direction, or mixing true and magnetic values within the same calculation, producing a heading that is off by roughly twice the variation.
The mnemonic is remembered as a phrase, not as a conversion direction, and charted courses are magnetic while winds aloft are often true, so the two get combined without a deliberate conversion step.
What to do instead
Sketch a small compass rose on the scratch sheet and label both true and magnetic north before touching the numbers. Convert everything to one reference - usually true - compute the wind correction and ground speed, then convert back once at the end and sanity-check that the result lies between the course and the wind direction.
Assuming the pilot in command may amend, delay, or cancel a dispatch release on their own authority, or that the dispatcher's role is advisory once the aircraft departs.
Candidates carry over the private or commercial pilot mental model where the pilot is the sole authority, and the joint-responsibility concept is easy to state but rarely applied to a scenario.
What to do instead
Anchor on the regulatory text: the release is issued jointly and cannot be changed without the dispatcher's concurrence while the dispatcher is on duty. For each scenario question, first ask 'who is required to agree?' and only then evaluate the operational merits of the change.
In emergency or abnormal scenario items, jumping straight to a system action or a diversion without first establishing aircraft control, declaring the emergency, or identifying the crew's hazardous attitude; the chosen answer is a plausible procedure but out of sequence.
Scenario stems are written to reward priorities, but the technical detail in the stem pulls attention toward the system, and hazardous-attitude questions read like personality descriptions rather than decision traps.
What to do instead
Apply a fixed filter to every scenario: aviate, then communicate and declare, then run the checklist, then replan. For human-factors items, name the attitude out loud (impulsivity, invulnerability, macho, resignation, anti-authority) before selecting the countermeasure.
Submitting the first fuel and time computation after a late change - added payload, a revised wind forecast, or a lower cruise altitude - without rebuilding the plan, and answering questions about the flight as if the original numbers still applied.
Once a full plan has been computed, the numbers feel settled; the revision is treated as an adjustment to a finished product rather than as an input that invalidates it.
What to do instead
Treat any change in payload, routing, altitude, or wind as a trigger to rerun the whole ladder and to recheck every downstream limit (takeoff weight, landing weight, reserve, ETA). Note the trigger and the new values side by side so the comparison is explicit rather than assumed.