← All explained questions · Supplemental · II — Preflight Procedures
A FROST-COVERED wing exhibits which characteristic?
Choices
Lower stall speed.
Frost INCREASES stall speed.
✓ HIGHER stall speed and reduced lift.correct
even very thin frost (smaller than sandpaper) disrupts airflow, increasing stall speed by up to 30% and reducing lift coefficient. Always remove frost before takeoff. Frost-covered wings = higher stall speed + lower lift coefficient. Even sandpaper-thin frost disrupts the boundary layer enough to degrade lift up to 30% and raise stall speed similarly. Many fatal accidents have occurred from pilots taking off with 'just a little frost.' Always physically remove frost before flight; defrost spray may be available, otherwise wait for sun/temperature.
Improved stall recovery.
Frost worsens stall recovery, doesn't improve.
No effect on performance.
Frost has significant negative effect.
Why
even very thin frost (smaller than sandpaper) disrupts airflow, increasing stall speed by up to 30% and reducing lift coefficient. Always remove frost before takeoff. Frost-covered wings = higher stall speed + lower lift coefficient. Even sandpaper-thin frost disrupts the boundary layer enough to degrade lift up to 30% and raise stall speed similarly. Many fatal accidents have occurred from pilots taking off with 'just a little frost.' Always physically remove frost before flight; defrost spray may be available, otherwise wait for sun/temperature.
FAA source: FAA-H-8083-25C, PHAK Ch. 5, aerodynamic effects; AC 91-74 if frost/ice contextbrowse the reference library →
Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.