By Joshua Foltz, First Officer, Allegiant Air

Garret Healy, Software Engineer, Jeppesen Inc.

Abstract:

The author’s developed the following tables as a crew planning tool. These tables demonstrate how strict FAR Part 117 work rules are in relation to allowed duty time when compared to FAR part 121 subpart Q.

Airlines must schedule efficient Flight Duty Periods and carefully plan when Flight Duty Periods begin as well as how many segments are involved.

In order to schedule efficient pairings the Airlines should consider looking at productive hours (block time) versus non-productive hours (FDP time).

Definitions:

Duty:

Is defined in FAR part 117.

Means any task that a flightcrew member performs as required by the certificate holder, including but not limited to flight duty period, flight duty, pre- and post-flight duties, administrative work, training, deadhead transportation, aircraft positioning on the ground, aircraft loading, and aircraft servicing.

Pre-Flight Duties:

Includes reporting for an assignment, acknowledging flights to be performed while on duty, will be operated in accordance to FAA regulations, including understanding of the expected conditions that will affect the flight(s) to be performed. Inspections of the aircraft for flight readiness, etc.

Flight Duty Period (FDP):

Is defined in FAR part 117.

Means a period that begins when a flightcrew member is required to report for duty with the intention of conducting a flight, a series of flights, or positioning or ferrying flights, and ends when the aircraft is parked after the last flight and there is no intention for further aircraft movement by the same flightcrew member. A flight duty period includes the duties performed by the flightcrew member on behalf of the certificate holder that occur before a flight segment or between flight segments without a required intervening rest period. Examples of tasks that are part of the flight duty period include deadhead transportation, training conducted in an aircraft or flight simulator, and airport/standby reserve, if the above tasks occur before a flight segment or between flight segments without an intervening required rest period.

Flight Time:

Is defined in FAR part 1.

Commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing.

Flightcrew Member (FCM):

Is defined in FAR part 1.

Is a pilot, flight engineer, or flight navigator assigned to duty in an aircraft during flight time.

Assumptions:

Brief time:

The amount of pre-flight duty before the flight departs the gate. Typically ranges between 0:45 to 1:00; generally contained within a CBA; for the purposes of this paper we will use 1:00.

Debrief time:

The amount of post-flight duty after the flight arrives at the gate. Typically ranges between 0:15 to 0:30; generally contained within a CBA; for the purposes of this paper we will use 0:15.

Flight Time Buffer:

The amount of time used to schedule a FCM within the permissible limitations of FAR part 117.11, for the purposes of this paper we will use 0:30.

Minimum Connect Time:

The minimum time from when an aircraft arrives at the gate, to the time when the aircraft moves away from the gate to allow for sufficient to unload/load passengers and baggage, and make any required service needs for the aircraft before departure as well as performance of pre-flight checklists, for the purposes of this paper we will use 0:45.

Permissible Extensions to FDP:

Under FAR 117.19, it is permissible to operate beyond the scheduled limitations in FAR 117.13 by 0:30, extensions up 2:00 may be conducted before departure under certain conditions, for the purposes of this paper we will use 0:30.

Cumulative Flight Time Limitations:

For the purposes of this paper, a FCM will not be exceeding any of the following limitations:

1 Under 117.23, FCM’s are limited to 100 hours in 672 consecutive hours and 1000 hours in 365 calendar days.

2 Under 121 subpart Q, FCM’s are limited to 30 hours in 7 calendar days, 100 hours in a calendar months and 1000 hours in a calendar year.

Cumulative Flight Duty Time Limitations:

For the purposes of this paper, a FCM will not be exceeding any of the following limitations:

1 Under 117.23, FCM’s are limited to 60 hours in 168 consecutive hours and 190 hours in 672 consecutive hours.

2 Under 121 subpart Q, FCM’s are presently not limited by FDP time.

Rest Requirements:

For the purposes of this paper, a FCM will always be in compliance with the following requirements:

1 Under 117.25, FCM’s are required to have been scheduled for and have been given a rest period of no less than 30 hours in the 168 consecutive hours preceding the start of a FDP.

2 Under 121 subpart Q, FCM’s are required to have been scheduled for and have been given a rest period of no less than 24 hours in the 7 calendar days preceding the scheduled completion of any flight subject to this subpart.

Specific regulatory provisions applied:

Daily Flight Time Limitations (FTL):

1 Part 117 has Daily FTL’s governed under 117.11.

Based upon FDP start time, the limitation is either 8:00 or 9:00 as defined in Table A.

Evaluated on a leg by leg basis, FCM may not continue a flight if before takeoff it is known that the FTL will be violated.

Table A

2 Part 121 has Daily FTL’s governed under 121.471(a)(4).

The scheduled limitation is 8:00.

A FCM may continue the assigned FDP as long as the flight itinerary is the same as what the FCM began with no further constraints (legal to start, legal to finish), else a reevaluation at the point of rescheduling must take place.

Daily FDP Limitations:

1 Part 117 has Daily FTL’s governed under 117.13.

Based upon FDP start time, the scheduled limitation is defined in Table B.

Extensions to the assigned FDP are permitted in accordance with 117.19.

Table B

2 Part 121 does not actually have FDP limitations, instead a complicated system based upon 121.471(b) and (c):

A scheduled flight time in the 24 hours preceding the scheduled completion of a flight segment.

A required rest period in the 24 hours preceding the actual expected completion of a flight segment. The may be reduced due to operational contingencies before takeoff.

A compensatory rest period will be required following the release of a duty period that is preceded by a reduced rest period, this will effectively limit the duty period to a maximum of 16 or 15 hours dependent upon the scheduled flight time in the 24 hour period, and the compensatory rest period must commence within 24 hours of the start of the reduced rest period.

Objective comparisons of specific regulatory provisions:

FAR 121 Subpart Q

(Max Duty Time – Max Extension) – ((Max Flight Time – Flt buffer) + Brief + Debrief + (Segments – 1) * Turn) = Allowed Flight Duty Period delay

Relative Efficiency of the FDP

100 * (Max Flight Time)/((max duty time – debrief) + Permitted Pairing Growth)

FAR 117

(Max Skd FDP + Max Extension) – ((Max Flight Time – FT Buffer) + Brief + (Segments – 1) * Turn) = Allowed Flight Duty Period delay

(Max Skd FDP + Max Extension) – ((Max Flight Time) + Brief + (Segments – 1) * Turn) = Required Reduction of Flight Time

Relative FDP Efficiency

100 * (Max Flight Time- Required reduction of Flight Time)/(max skd FDP + Permitted Pairing Growth)

Conclusions:

FAR 117 when compared to FAR part 121 subpart Q, overall the pairings will have less productivity; however, a concentration of FDP starts from 0500 to 1650 with 5 segments will produce an increase in efficiency of 2.76 percent, a secondary window with 3 or 4 segments from 17:00 to 04:59, with a 0.98 increase. The increase in efficiency in the first window is primarily the result of the decrease in permitted FDP time due to the increase in the number of flight segments, while the increase in the second window is primarily due to the decrease in permitted FDP as a result of the diurnal component.

FAR 117 will have two “Sweet Spots” to absorb delays, the first between 07:00 to 12:59, and the second between 20:00 and 21:59.

FAR 117 through all time frames will require flight time reduction to allow for the ability to absorb delays when FCM are scheduled for six (6) or more flight segments.

Recommendations:

The authors’ recommend that airline management agree upon a specific company “buffer time” between maximum scheduled flight time from maximum allowed FAA flight time. For example, perhaps airlines could clarify a 20 minute buffer from maximum FAA flight time. For example, the company maximum flight time could be 7:40 or 8:40 scheduled flight time depending on what time the flight crew member starts. This “buffer time” may be higher in the winter time than the summer time. Perhaps actual data can be collected from past months of flying to agree upon a conservative but logic buffer time. In the real world extensions are an option to complete the pairing.

how-maximum-flight-duty-periods-and-maximum-flight-times-will-affect-airlines