background image

AIM 

6/17/21 

is authorized to conduct the climb or descent at any 
rate, and to temporarily level off at any intermediate 
altitude as desired. However, once the aircraft has 
vacated an altitude, it may not return to that altitude. 

d. 

When ATC has not used the term “AT PILOT’S 

DISCRETION” nor imposed any climb or descent 
restrictions, pilots should initiate climb or descent 
promptly on acknowledgement of the clearance. 
Descend or climb at an optimum rate consistent with 
the operating characteristics of the aircraft to 
1,000 feet above or below the assigned altitude, and 
then attempt to descend or climb at a rate of between 
500 and 1,500 fpm until the assigned altitude is 
reached. If at anytime the pilot is unable to climb or 
descend at a rate of at least 500 feet a minute, advise 
ATC. If it is necessary to level off at an intermediate 
altitude during climb or descent, advise ATC, except 
when leveling off at 10,000 feet MSL on descent, or 
2,500 feet above airport elevation (prior to entering a 
Class C or Class D surface area), when required for 
speed reduction. 

REFERENCE

 

14 CFR Section 91.117. 

NOTE

 

Leveling off at 10,000 feet MSL on descent or 2,500 feet 
above airport elevation (prior to entering a Class C or 
Class D surface area) to comply with 14 CFR 
Section 91.117 airspeed restrictions is commonplace. 
Controllers anticipate this action and plan accordingly. 
Leveling off at any other time on climb or descent may 
seriously affect air traffic handling by ATC. Consequently, 
it is imperative that pilots make every effort to fulfill the 
above expected actions to aid ATC in safely handling and 
expediting traffic. 

e. 

If the altitude information of an ATC 

DESCENT clearance includes a provision to 
“CROSS (fix) AT” or “AT OR ABOVE/BELOW 
(altitude),” the manner in which the descent is 
executed to comply with the crossing altitude is at the 
pilot’s discretion. This authorization to descend at 
pilot’s discretion is only applicable to that portion of 
the flight to which the crossing altitude restriction 
applies, and the pilot is expected to comply with the 
crossing altitude as a provision of the clearance. Any 
other clearance in which pilot execution is optional 
will so state “AT PILOT’S DISCRETION.” 

EXAMPLE

 

1. 

“United Four Seventeen, descend and maintain 

six thousand.” 

NOTE

 

1. 

The pilot is expected to commence descent upon receipt 

of the clearance and to descend at the suggested rates until 
reaching the assigned altitude of 6,000 feet. 

EXAMPLE

 

2. 

“United Four Seventeen, descend at pilot’s discretion, 

maintain six thousand.” 

NOTE

 

2. 

The pilot is authorized to conduct descent within the 

context of the term at pilot’s discretion as described above. 

EXAMPLE

 

3. 

“United Four Seventeen, cross Lakeview V

O

R at or 

above Flight Level two zero zero, descend and maintain 
six thousand.” 

NOTE

 

3. 

The pilot is authorized to conduct descent at pilot’s 

discretion until reaching Lakeview VOR and must comply 
with the clearance provision to cross the Lakeview VOR at 
or above FL 200. After passing Lakeview VOR, the pilot is 
expected to descend at the suggested rates until reaching 
the assigned altitude of 6,000 feet. 

EXAMPLE

 

4. 

“United Four Seventeen, cross Lakeview V

O

R at 

six thousand, maintain six thousand.” 

NOTE

 

4. 

The pilot is authorized to conduct descent at pilot’s 

discretion, however, must comply with the clearance 
provision to cross the Lakeview VOR at 6,000 feet. 

EXAMPLE

 

5. 

“United Four Seventeen, descend now to Flight 

Level two seven zero, cross Lakeview V

O

R at or below 

one zero thousand, descend and maintain six thousand.” 

NOTE

 

5. 

The pilot is expected to promptly execute and complete 

descent to FL 270 upon receipt of the clearance. After 
reaching FL 270 the pilot is authorized to descend “at 
pilot’s discretion” until reaching Lakeview VOR. The pilot 
must comply with the clearance provision to cross 
Lakeview VOR at or below 10,000 feet. After Lakeview 
VOR the pilot is expected to descend at the suggested rates 
until reaching 6,000 feet. 

EXAMPLE

 

6. 

“United Three Ten, descend now and maintain Flight 

Level two four zero, pilot’s discretion after reaching Flight 
Level two eight zero.” 

NOTE

 

6. 

The pilot is expected to commence descent upon receipt 

of the clearance and to descend at the suggested rates until 
reaching FL 280. At that point, the pilot is authorized to 
continue descent to FL 240 within the context of the term 
“at pilot’s discretion” as described above. 

f. 

In case emergency authority is used to deviate 

from provisions of an ATC clearance, the pilot

in

 

4

4

ATC Clearances and Aircraft Separation