This is the Fair Labor Standards Act (FLSA) 27 day cycle calendar as utilized by the City of Jacksonville, Florida in regards to Firefighters who are assigned to a 56 hour work week schedule.
These employees receive four hours overtime pay if they are present at work every shift during a cycle.
The overtime is forfeited if ANY leave time is taken during a cycle.*
Note that utilizing a leave of absence (LOA swap day) does not forfeit the overtime.

How to use the calendar:

• Find the two columns for your shift.

• The start day for each cycle is in the left column.

• The end day is in the right column.

• Schedule leave time to fall on or between the start and end dates of each cycle.

Example:
Let's say you work A shift and want to take a vacation October 2011.
You can start your vacation on October 16 and end it on November 09 and you only lose the overtime in that cycle.
If you start you vacation on October 16 and come back to work November 12, you will lose the overtime for two cycles.
You took off October 16 which falls in one cycle and November 12, which falls into the next cycle.

If you have a vacation that will fall in two cycles, use your leave time in one cycle and LOA swaps in the other.
Better yet, Only use LOA swap time and you'll be good!

ABOUT FLSA

The FLSA is the law that says if a regular worker works over 40 hours in one week, they MUST be paid time and one half pay (overtime) for the excess hours worked.
Firefighters and police are exempted from this rule and must work many more hours before being paid overtime.
The government agency that employs the firefighter gets to choose a cycle between seven and twenty eight days.
The city of Jacksonville chose a twenty seven day cycle. That's why we have this convoluted calendar.
 

Section 7(k) of the FLSA provides that employees engaged in fire protection or law enforcement may be paid overtime on a "work period" basis. A "work period" may be from 7 consecutive days to 28 consecutive days in length. For example, fire protection personnel are due overtime under such a plan after 212 hours worked during a 28-day period, while law enforcement personnel must receive overtime after 171 hours worked during a 28-day period. For work periods of at least 7 but less than 28 days, overtime pay is required when the number of hours worked exceeds the number of hours which bears the same relationship to 212 (fire) or 171 (police) as the number of days in the work period bears to 28.

At 40 hours per week, your regular worker puts in 160 hours in a 28 day period (40 x 4 = 160).
A firefighter works nine 24 hour shifts in a 28 day period for a total of 216 hours.(9 x 24 = 216)
Using section 7(k) the firefighter is due only four hours of overtime.
A regular worker would get 56 hours of overtime by working 216 hours in his 28 day cycle.

* JFRD Employees on a fifty-six (56) hour schedule shall receive extra compensation at the rate of one-half (1/2) their regular rate of pay for normally scheduled hours worked in excess of two hundred four (204) hours during the twenty-seven day work period. For purposes of this subsection, the term "hours worked" shall only include, in addition to regular duty hours, military leave, Union pool time, and special assignments, and LOA (swap time).