AIM Text
- Providing airborne assistance to another aircraft may involve flying in very close proximity to that aircraft. Most pilots receive little, if any, formal training or instruction in this type of flying activity. Close proximity flying without sufficient time to plan (i.e., in an emergency situation), coupled with the stress involved in a perceived emergency can be hazardous.
- The pilot in the best position to assess the situation should take the responsibility of coordinating the airborne intercept and inspection, and take into account the unique flight characteristics and differences of the category(s) of aircraft involved.
- Some of the safety considerations are:
- Area, direction and speed of the intercept;
- Aerodynamic effects (i.e., rotorcraft downwash);
- Minimum safe separation distances;
- Communications requirements, lost communications procedures, coordination with ATC;
- Suitability of diverting the distressed aircraft to the nearest safe airport; and
- Emergency actions to terminate the intercept.
- Close proximity, inflight inspection of another aircraft is uniquely hazardous. The pilot-in-command of the aircraft experiencing the problem/emergency must not relinquish control of the situation and/or jeopardize the safety of their aircraft. The maneuver must be accomplished with minimum risk to both aircraft.
Source: FAA Aeronautical Information Manual · current edition · paragraph 7-6-11.
Research Notes
AIM 7-6-11 covers Antifreeze and De-icing Fluids — the chemical agents used to remove and prevent frost/ice from aircraft.
Type I fluid: Heated (~140°F), unthickened. Primary use: removing existing ice/snow. Limited "holdover time" — provides minimal protection against new accumulation.
Type II/III/IV fluid: Thickened, holdover-effective. Applied after Type I to provide protection from refreezing during taxi and takeoff. The thicker fluid shears off on takeoff roll.
Holdover time: The time between deicing application and takeoff when the aircraft is protected from new ice accumulation. Published holdover times (in minutes) depend on fluid type, temperature, precipitation type, and intensity.
Reference: SAE AMS 1428 (Type II/III/IV); SAE AMS 1424 (Type I); AIM 7-6-11; AC 120-58 (Pilot Guide for De-Icing and Anti-Icing Fluids).