The latest version of the ForeFlight electronic flight bag app includes a new runway analysis feature, which is available to Performance-level subscribers as a paid add-on service. Runway analysis launched with six Cessna Citation models, but ForeFlight is adding more jets and eventually turboprops as well.
Runway analysis allows pilots to fly with the maximum payload possible while meeting terrain- and obstacle-clearance requirements in case of loss of one engine during the takeoff phase of flight. Airlines have long used runway analysis engine-out procedures (EOPs) to allow dispatchers to calculate the highest possible maximum takeoff weight for specific runways while meeting minimum climb, available runway length, and obstacle clearance and other requirements. Runway analysis has increasingly become part of normal operations in business aviation, with analysis companies providing EOPs for many airports globally. While EOPs generally include straight-out takeoff and climb procedures, some EOPs may be designed to match airport departure procedures or standard instrument departures (SIDs). Other EOPs may dictate a different departure path that must be used in case of an engine-out emergency.
ForeFlight’s runway analysis incorporates flight manual constraints such as brake energy and tire speed limits as well as minimum climb gradient, runway length, and obstacle clearance. A team of ForeFlight geographic information system and performance experts has developed engine-out procedures (EOPs) for a variety of airports starting in the U.S., and these will be expanded worldwide. The EOPs are in compliance with recommendations in FAA Advisory Circular 120-91A and its ICAO counterpart.
The first jets to be enabled in the ForeFlight app for runway analysis are the Citation Mustang, M2, CJ3/3+, CJ4, and XLS+. The runway analysis is per-model for individual users ($600 per year) or for a group of pilots for larger operations bundled packages are available. Each aircraft’s configuration and weight-and-balance information is incorporated, although owners and operators probably already have keyed in this information if they’ve been using ForeFlight previously. ForeFlight Dispatch users have the same access to the new runway analysis features, and it is available on the iPad and iPhone versions of ForeFlight but not the web version.
To access the runway analysis, a user needs to create a flight in the "Flights" tab. If runway analysis is available for the selected departure and arrival airports and the selected airplane is enabled, a “Takeoff” and “Landing” button will appear in the departure and destination fields, respectively.
After setting the fuel policy and passenger/cargo weights, pressing the "Takeoff" button shows the "Takeoff Analysis" page with all the information for departing, along with variables that the user can change. At the top is a handy summary of the takeoff information, including maximum takeoff weight (mtow), field length, V1/VR/V2/VENR, level-off altitude, and the reason for the mtow limitation (for example, brake temperature, structural weight, obstacles, etc.). The allowable mtow is shown so the pilot can quickly try different payloads or switching runways or EOPs to see if that allows a higher mtow.
The user can choose to use the current or forecast weather or input weather information manually. ForeFlight automatically adjusts the fuel load if the weight limit is exceeded or offers a runway with more favorable winds, if available. These automatic features help simplify the decision-making process, according to ForeFlight.
There are two types of landing information available. The first is for an emergency return to the departure airport, and this includes the landing weight, actual runway distance, VAPP, and VREF. The second is for the destination airport and includes the same information. In both cases, the pilot can select variables such as surface condition and landing factor, and manually input weather information.
The calculations happen instantly, enabling rapid testing of different scenarios and optimization for the existing conditions, including changes in aircraft configuration such as various flaps and anti-ice settings.
For takeoff, users have a choice of three EOPs. The first is a Jeppesen EOP, which is based on VOR and DME navigation. These were developed a while ago for airlines and might not be suitable for business aircraft with modern GPS avionics. (Jeppesen and ForeFlight are sister companies, both owned by Boeing.) Most runways have straight-out EOPs, but because of terrain- and obstacle-clearance requirements, at many airports payload capacity will be limited for these procedures. The other EOPs are the RNAV procedures developed by the ForeFlight GIS team, and these use GPS waypoints to define the route to fly in case of engine failure after takeoff.
When using an EOP to maximize takeoff weight, pilots must follow that EOP to maintain the required clearance from obstacles and terrain. Not all EOPs follow the same routing as SIDs or the flight-planned departure. But the ForeFlight team, according to aircraft performance engineer Michael Vogt, when possible tries to match SIDs to make flying the EOP simpler and avoid the need to program an alternate flight plan in case of engine failure.
“The crew will probably have the SID programmed into the FMS,” he explained. “If they do have a failure, then they can quickly adapt to the EOP by flying the first portion of the departure, which may match the SID.”
In the EOP section of the takeoff information, the three EOPs are shown, and clicking on each one shows the mtow limitation and the exact procedure to fly. For example, taking off from Eagle County Regional Airport in Colorado, the ForeFlight EOP exactly matches the BEVVR1 departure, so there is no need to input an alternate flight plan.
One option for takeoffs is to add custom obstacles, which require entering the distance from and height above the departure end of the runway.
Once the pilot is done entering the data and is satisfied with the performance information, pressing the Summary button delivers a document with all the information about the takeoff and landing. This can easily be shared via email or text, printed, saved, or marked up. The summary includes charts showing the three EOPs and landing analysis for each runway. The EOPs are shown for three different temperatures in case that changes after planning the flight. The landing analysis considers both zero wind and 10 knots of tailwind for each runway at the destination, with both the normal and factored landing distances.
ForeFlight is adding many more aircraft to the runway analysis service, starting with new business jets. Eventually, it will cover older jets and multiengine turboprops like the King Air series. “We are working with the OEMs and we do have a plan for the rest of the year to roll out more aircraft,” said Vogt.