# Early Morning Concurrent Session: Aviation Management and Operations: Presentation: Determining the Runway Point-of-No-Return for Landing Roll Go-Around in Transport Category Airplanes

## Location

San Marcos Ballroom B

## Topic Area

COMMERCIAL AVIATION

## Other Topic Area

AIR TRAFFIC MANAGEMENT, HUMAN FACTORS

## Abstract

This research addresses the problem of the definition and calculation of the landing point-of-no-return (PNR) or, as it is sometimes called, commit-to-land (NTSB) point. PNR is a longitudinal location on a runway after which it is not recommended to attempt aborting landing-roll deceleration and conduct acceleration go-around (takeoff). This is essentially a touch-and-go maneuver that includes substantial deceleration before “go” is conducted. One of the possible reasons why go-around after touchdown would be attempted is realization of inadequate braking performance and insufficient runway remaining for stopping which is especially critical during contaminated runway operations or landing long. Although much has been written about Rejected Takeoffs (RTOs) which is standard mandatory part of pilot training curriculum, very little is known about the go-arounds after landing touchdown in transport-category (FAR/CS 25) airplanes. In a sense this maneuver is the inverse of takeoff’s accelerate stop-or-go (AS-AG) decision and both cases usually involve engine-out (OEI) scenarios. A go-around after touchdown can be safely performed if sufficient remaining runway is available, sufficient airplane kinetic energy, and the airplane configuration is favorite. Generally, once the thrust reversers have been deployed no attempt to go-around and lift-off is recommended. A mathematical model based on the integral equations for linear momentum and energy was used in this study and the calculations have been performed for a typical midsize business jet and a large transport category airplane for various scenarios of wind conditions, runway contamination levels and landing distance available, braking efficiency, touchdown point, configuration, etc. Best pilot practices and operational techniques can be designed based on the results of computations incorporating human factors studies. It is always better to accept runway overrun at slow speed then risk impossible takeoffs. However, if the conditions are right, a go-around after touchdown can be safely performed if the runway PNR has not been reached. The dynamic PNR can be monitored and continuously recalculated by the Total-Runway-Safety-System (TRSS) algorithms and the recommendations made available to pilots on common displays for decelerate-go or decelerate-stop decisions.

## Start Date

16-1-2016 8:00 AM

## End Date

16-1-2016 9:15 AM

## Chair/Note/Host

Chair: Hon. Robert Sumalt, National Transportation Safety Board

## Keywords

Aviation, Go-Around after touchdown, Contaminated runway, Runway overrun, Decelerate-Go, Decelerate-Stop, Engine-Failure on Go-Around, Runway Point-of-No-Return, Transport Category Airplane, Transport Category

## Share

COinS

Jan 16th, 8:00 AM Jan 16th, 9:15 AM

Early Morning Concurrent Session: Aviation Management and Operations: Presentation: Determining the Runway Point-of-No-Return for Landing Roll Go-Around in Transport Category Airplanes

San Marcos Ballroom B

This research addresses the problem of the definition and calculation of the landing point-of-no-return (PNR) or, as it is sometimes called, commit-to-land (NTSB) point. PNR is a longitudinal location on a runway after which it is not recommended to attempt aborting landing-roll deceleration and conduct acceleration go-around (takeoff). This is essentially a touch-and-go maneuver that includes substantial deceleration before “go” is conducted. One of the possible reasons why go-around after touchdown would be attempted is realization of inadequate braking performance and insufficient runway remaining for stopping which is especially critical during contaminated runway operations or landing long. Although much has been written about Rejected Takeoffs (RTOs) which is standard mandatory part of pilot training curriculum, very little is known about the go-arounds after landing touchdown in transport-category (FAR/CS 25) airplanes. In a sense this maneuver is the inverse of takeoff’s accelerate stop-or-go (AS-AG) decision and both cases usually involve engine-out (OEI) scenarios. A go-around after touchdown can be safely performed if sufficient remaining runway is available, sufficient airplane kinetic energy, and the airplane configuration is favorite. Generally, once the thrust reversers have been deployed no attempt to go-around and lift-off is recommended. A mathematical model based on the integral equations for linear momentum and energy was used in this study and the calculations have been performed for a typical midsize business jet and a large transport category airplane for various scenarios of wind conditions, runway contamination levels and landing distance available, braking efficiency, touchdown point, configuration, etc. Best pilot practices and operational techniques can be designed based on the results of computations incorporating human factors studies. It is always better to accept runway overrun at slow speed then risk impossible takeoffs. However, if the conditions are right, a go-around after touchdown can be safely performed if the runway PNR has not been reached. The dynamic PNR can be monitored and continuously recalculated by the Total-Runway-Safety-System (TRSS) algorithms and the recommendations made available to pilots on common displays for decelerate-go or decelerate-stop decisions.