4/20/23 

AIM 

Section 4.  Two-way Radio Communications Failure 

6

−

4

−

1.  Two-way Radio Communications Failure 

a. 

It is virtually impossible to provide regulations and procedures applicable to all possible situations 

associated with two-way radio communications failure. During two-way radio communications failure, when 

confronted by a situation not covered in the regulation, pilots are expected to exercise good judgment in whatever 

action they elect to take. Should the situation so dictate they should not be reluctant to use the emergency action 

contained in 14 CFR Section 91.3(b). 

b. 

Whether two-way communications failure constitutes an emergency depends on the circumstances, and in 

any event, it is a determination made by the pilot. 14 CFR Section 91.3(b) authorizes a pilot to deviate from any 

rule in Subparts A and B to the extent required to meet an emergency. 

c. 

In the event of two-way radio communications failure, ATC service will be provided on the basis that the 

pilot is operating in accordance with 14 CFR Section 91.185. A pilot experiencing two-way communications 

failure should (unless emergency authority is exercised) comply with 14 CFR Section 91.185 quoted below: 

1.  General. 

Unless otherwise authorized by ATC, each pilot who has two-way radio communications 

failure when operating under IFR must comply with the rules of this section. 

2.  VFR conditions. 

If the failure occurs in VFR conditions, or if VFR conditions are encountered after the 

failure, each pilot must continue the flight under VFR and land as soon as practicable. 

NOTE

−

 

This procedure also applies when two-way radio failure occurs while operating in Class A airspace. The primary objective 
of this provision in 

14 CFR Section 

91.185 is to preclude extended IFR operation by these aircraft within the ATC system. 

Pilots should recognize that operation under these conditions may unnecessarily as well as adversely affect other users of 

the airspace, since ATC may be required to reroute or delay other users in order to protect the failure aircraft. However, it 

is not intended that the requirement to “land as soon as practicable” be construed to mean “as soon as possible.” Pilots 

retain the prerogative of exercising their best judgment and are not required to land at an unauthorized airport, at an airport 

unsuitable for the type of aircraft flown, or to land only minutes short of their intended destination. 

3.  IFR conditions. 

If the failure occurs in IFR conditions, or if subparagraph 2 above cannot be complied 

with, each pilot must continue the flight according to the following: 

(a)  Route. 

(1) 

By the route assigned in the last ATC clearance received; 

(2) 

If being radar vectored, by the direct route from the point of radio failure to the fix, route, or airway 

specified in the vector clearance; 

(3) 

In the absence of an assigned route, by the route that ATC has advised may be expected in a further 

clearance; or 

(4) 

In the absence of an assigned route or a route that ATC has advised may be expected in a further 

clearance by the route filed in the flight plan. 

(b)  Altitude. 

At the HIGHEST of the following altitudes or flight levels FOR THE ROUTE SEGMENT 

BEING FLOWN: 

(1) 

The altitude or flight level assigned in the last ATC clearance received; 

(2) 

The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in 14 CFR 

Section 91.121(c)) for IFR operations; or 

(3) 

The altitude or flight level ATC has advised may be expected in a further clearance. 

Two-way Radio Communications Failure 

6

−

4

−

1