While Part 121 and 135 operators are the primary users of takeoff minimums, they may be able to use alternative takeoff minimums based on their individual OpsSpecs. Through these OpsSpecs, operators are authorized to depart with lower-than-standard minimums provided they have the necessary equipment and crew training.


Operations specifications (OpsSpecs) are required by Part 119.5 to be issued to commercial operators to define the appropriate authorizations, limitations, and procedures based on their type of operation, equipment, and qualifications. The OpsSpecs can be adjusted to accommodate the many variables in the air transportation industry, including aircraft and aircraft equipment, operator capabilities, and changes in aviation technology. The OpsSpecs are an extension of the CFR; therefore, they are legal, binding contracts between a properly certificated air transportation organization and the FAA for compliance with the CFR's applicable to their operation. OpsSpecs are designed to provide specific operational limitations and procedures tailored to a specific operator's class and size of aircraft and types of operation, thereby meeting individual operator needs.

Part 121 and 135 operators have the ability, through the use of approved OpsSpecs, to use lower-than-standard takeoff minimums. Depending on the equipment installed in a specific type of aircraft, the crew training, and the type of equipment installed at a particular airport, these operators can depart from appropriately equipped runways with as little as 300 feet RVR. Additionally, OpsSpecs outline provisions for approach minimums, alternate airports, and weather services in Part 119 and FAA Order 8400.10, Air Transportation Operations Inspector’s Handbook.


As technology improves over time, the FAA is able to work in cooperation with specific groups desiring to use these new technologies. Head-up guidance system (HGS) is an example of an advanced system currently being used by some airlines. Air carriers have requested the FAA to approve takeoff minimums at 300 feet RVR. This is the lowest takeoff minimum approved by OpsSpecs. As stated earlier, only specific air carriers with approved, installed equipment, and trained pilots are allowed to use HGS for decreased takeoff minimums. [Figure 2-9]


All takeoffs and departures have visibility minimums (some may have minimum ceiling requirements) incorporated into the procedure. There are a number of methods to report visibility, and a variety of ways to distribute these reports, including automated weather observations. Flight crews should always check the weather, including ceiling and visibility information, prior to departure. Never launch an IFR flight without obtaining current visibility information immediately prior to departure. Further, when ceiling and visibility minimums are specified for IFR departure, both are applicable.

Weather reporting stations for specific airports across the country can be located by reviewing the A/FD. Weather sources along with their respective phone numbers and frequencies are listed by airport. Frequencies for weather sources such as automatic terminal information service (ATIS), digital automatic terminal information service (D-ATIS), Automated Weather Observing System (AWOS), Automated Surface Observing System (ASOS), and FAA Automated Flight Service Station (AFSS) are published on approach charts as well. [Figure 2-10]


Runway visual range (RVR) is an instrumentally derived value, based on standard calibrations, that represents the horizontal distance a pilot will see down the runway from the approach end. It is based on the sighting of either high intensity runway lights or on the visual contrast of other targets whichever yields the greater visual range. RVR, in contrast to prevailing or runway visibility, is based on what a pilot in a moving aircraft should see looking down the runway. RVR is reported in hundreds of feet, so the values must be converted to statute miles if the visibility in statute miles is not reported. [Figure 2-11] This visibility measurement is updated every minute; therefore, the most accurate visibility report will come from the local controller instead of a routine weather report. Transmissometers near the runway measure visibility for the RVR report. If multiple transmissometers are installed, they provide reports for multiple locations, including touchdown RVR, mid-RVR, and rollout RVR. RVR visibility may be reported as RVR 5-5-5. This directly relates to the multiple locations from which RVR is reported and indicates 500 feet visibility at touchdown RVR, 500 feet at mid- RVR, and 500 feet at the rollout RVR stations.

RVR is the primary visibility measurement used by Part 121 and 135 operators, with specific visibility reports and controlling values outlined in their respective OpsSpecs. Under their OpsSpecs agreements, the operator must have specific, current RVR reports, if available, to proceed with an instrument departure. OpsSpecs also outline which visibility report is controlling in various departure scenarios.