AIM
4/20/23
NOTE
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The intent of the rule is that a pilot who has experienced two-way radio failure should select the appropriate altitude for
the particular route segment being flown and make the necessary altitude adjustments for subsequent route segments. If the
pilot received an “expect further clearance” containing a higher altitude to expect at a specified time or fix, maintain the
highest of the following altitudes until that time/fix:
(1) the last assigned altitude; or
(2) the minimum altitude/flight level for IFR operations.
Upon reaching the time/fix specified, the pilot should commence climbing to the altitude advised to expect. If the 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
EXAMPLE
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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.
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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.
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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
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Two-way Radio Communications Failure