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AIM

10/12/17

6−4−2

Two-way Radio Communications Failure

radio failure occurs after the time/fix specified, the altitude

to be expected is not applicable and the pilot should

maintain an altitude consistent with 1 or 2 above. If the

pilot receives an “expect further clearance” containing a

lower altitude, the pilot should maintain the highest of 1 or

2 above until that time/fix specified in subparagraph (c)

Leave clearance limit, below.
EXAMPLE−
1. A pilot experiencing two-way radio failure at an
assigned altitude of 7,000 feet is cleared along a direct
route which will require a climb to a minimum IFR altitude
of 9,000 feet, should climb to reach 9,000 feet at the time
or place where it becomes necessary (see 14 CFR
Section 91.177(b)). Later while proceeding along an
airway with an MEA of 5,000 feet, the pilot would descend
to 7,000 feet (the last assigned altitude), because that
altitude is higher than the MEA.
2. A pilot experiencing two-way radio failure while being
progressively descended to lower altitudes to begin an
approach is assigned 2,700 feet until crossing the VOR and
then cleared for the approach. The MOCA along the airway
is 2,700 feet and MEA is 4,000 feet. The aircraft is within
22 NM of the VOR. The pilot should remain at 2,700 feet
until crossing the VOR because that altitude is the
minimum IFR altitude for the route segment being flown.
3. The MEA between a and b: 5,000 feet. The MEA
between b and c: 5,000 feet. The MEA between c and d:
11,000 feet. The MEA between d and e: 7,000 feet. A pilot
had been cleared via a, b, c, d, to e. While flying between
a and b the assigned altitude was 6,000 feet and the pilot
was told to expect a clearance to 8,000 feet at b. Prior to
receiving the higher altitude assignment, the pilot
experienced two-way failure. The pilot would maintain
6,000 to b, then climb to 8,000 feet (the altitude advised to
expect). The pilot would maintain 8,000 feet, then climb to
11,000 at c, or prior to c if necessary to comply with an
MCA at c. (14 CFR Section 91.177(b).) Upon reaching d,
the pilot would descend to 8,000 feet (even though the MEA
was 7,000 feet), as 8,000 was the highest of the altitude
situations stated in the rule (14 CFR Section 91.185).

(c) Leave clearance limit.

(1) When the clearance limit is a fix from

which an approach begins, commence descent or

descent and approach as close as possible to the

expect further clearance time if one has been

received, or if one has not been received, as close as

possible to the Estimated Time of Arrival (ETA) as

calculated from the filed or amended (with ATC)

Estimated Time En Route (ETE).

(2) If the clearance limit is not a fix from

which an approach begins, leave the clearance limit

at the expect further clearance time if one has been

received, or if none has been received, upon arrival

over the clearance limit, and proceed to a fix from

which an approach begins and commence descent or

descent and approach as close as possible to the

estimated time of arrival as calculated from the filed

or amended (with ATC) estimated time en route.

6−4−2. Transponder Operation During

Two-way Communications Failure

a. If an aircraft with a coded radar beacon

transponder experiences a loss of two-way radio

capability, the pilot should adjust the transponder to

reply on Mode A/3, Code 7600.

b. The pilot should understand that the aircraft

may not be in an area of radar coverage.

6−4−3. Reestablishing Radio Contact

a. In addition to monitoring the NAVAID voice

feature, the pilot should attempt to reestablish

communications by attempting contact:

1. On the previously assigned frequency; or
2. With an FSS or *ARINC.

b. If communications are established with an FSS

or ARINC, the pilot should advise that radio

communications on the previously assigned frequen-

cy has been lost giving the aircraft’s position, altitude,

last assigned frequency and then request further

clearance from the controlling facility. The preceding

does not preclude the use of 121.5 MHz. There is no

priority on which action should be attempted first. If

the capability exists, do all at the same time.

NOTE−

*Aeronautical Radio/Incorporated (ARINC) is a commer-

cial communications corporation which designs,

constructs, operates, leases or otherwise engages in radio

activities serving the aviation community. ARINC has the

capability of relaying information to/from ATC facilities

throughout the country.