FAA Aircraft Dispatcher (ADX)Regulations (Part 121)Medium
A dispatcher is releasing a turbine-powered Part 121 flight during freezing drizzle. The certificate holder's FAA-approved ground deicing/anti-icing program, required under 14 CFR 121.629(c), primarily uses which factors to determine the applicable holdover time before the clean aircraft concept is compromised?
- AAircraft tail number and time since last maintenance check
- BType and intensity of precipitation and outside air temperature
- CRunway length and airport elevation only
- DPassenger load and center of gravity location
Show answer & explanationAnswer & explanation
Correct answer: B. Type and intensity of precipitation and outside air temperature
Holdover time tables, developed for use under the 121.629(c) ground deicing/anti-icing program, are based on the type and intensity of active precipitation along with outside air temperature, since these factors determine how quickly fluid protection degrades.
Why the other options are wrong
- A. Maintenance history does not affect fluid holdover time.
- C. Runway/airport data do not determine holdover time duration.
- D. Weight and balance are unrelated to icing fluid effectiveness.
Ground Deicing/Anti-Icing Program (121.629(c))
Requires an FAA-approved program using holdover time tables to ensure a clean aircraft prior to takeoff in icing conditions.
- Holdover time varies with precipitation type/intensity and OAT
- Program includes pre-takeoff contamination checks
- Supports compliance with the clean aircraft concept
Memory trick: Colder and heavier snow shrinks your holdover clock.