How answers are verified

Every answer in this bank was checked against a standard ATPL meteorology reference and against standard theory, in two independent passes — one to verify, a second to argue against the first. Twenty-four answers were corrected. Questions that could not be answered without a chart or coded report you were never shown were removed rather than left in.

The bank was audited and repaired: 161 printing defects fixed, 13 questions that had been split beyond recovery removed, and one wrong answer key corrected. A seeded random sample was verified answer by answer. Worked explanations — each one cited to the paragraph of the regulation it comes from — are now being written topic by topic, starting with separation minima, holding, altimetry and the visual and light signals. Questions whose answer cannot yet be traced to a source I hold are deliberately left without an explanation rather than given a plausible one.

Of the questions in this subject, the 187 written for the general navigation chapters have been through full verification: every numerical answer was recomputed from first principles rather than trusted, and twenty-three questions were removed — some needed a chart or almanac you were never shown, and three had simply been marked with the wrong answer. The remaining questions in this subject have not yet had that pass.

The twin-engine type notes were checked claim by claim against the manufacturer's approved flight manual. Two numeric errors were found and corrected — a load-factor limit and a fuel-quantity column. Two further figures that could not be traced to the manual were flagged rather than left standing.