6/17/21
AIM
TBL 7
−
2
−
1
TBL 7
−
2
−
2
Lowest Usable Flight Level
Lowest Flight Level Correction Factor
Altimeter Setting
(Current Reported)
Lowest Usable Flight
Level
29.92 or higher
180
29.91 to 28.92
190
28.91 to 27.92
200
Altimeter Factor
Correction Factor
29.92 or higher
None
29.91 to 29.42
500 feet
29.41 to 28.92
1000 feet
28.91 to 28.42
1500 feet
28.41 to 27.92
2000 feet
27.91 to 27.42
2500 feet
3.
When the minimum altitude per 14 CFR
Section 91.159 and 14 CFR Section 91.177 is above
18,000 feet MSL, the lowest usable flight level must
be the flight level equivalent of the minimum altitude
plus the number of feet specified in TBL 7
−
2
−
2. ATC
will accomplish this calculation.
EXAMPLE
−
The minimum safe altitude of a route is 19,000 feet MSL
and the altimeter setting is reported between 29.92 and
29.43 “Hg, the lowest usable flight level will be 195, which
is the flight level equivalent of 19,500 feet MSL (minimum
altitude (TBL 7
−
2
−
1) plus 500 feet).
Barometric Altimeter Errors and Setting Procedures
7
−
2
−
3