Professional Pilot, October 2016

Table 1 The effects of compound factors The end is closer than you think 3 Increase landing speed With each 10 increase in landing speed increase landing distance by 20 4 Runway slope 10 increase in landing distance for each 1 downhill 5 Tailwind For each 10Kts increase landing distance by 21 3 Excessive airspeed over the runway Energy management is critical for all aircraft on landing At some point in the approach the ability to dissipate excess energy airspeed and or altitude ceases Large aircraft are generally more critical as the energy created with excess airspeed at touchdown is much greater than for small aircraft 4 Landing weight Heavier airplanes must dissipate more energy on landing A 10 increase in gross weight at landing results in a 5 increase in landing velocity and a 10 increase in landing distance 5 Landing beyond the desired touchdown point If unable to transition to landing at the desired point executing a missed approach is the only safe alternative 6 Downhill runway slope Excessive runway gradient is noted in the chart supplement and marked on the approach documents A negative downhill runway slope of 1 increases landing distance by 10 even with an on speed arrival Reviewing runway gradient at any new destination should always be included in the arrival briefing 7 Excessive height over the runway 68 PROFESSIONAL PILOT October 2016 The End threshold The certified landing distances furnished in the AFM are based on the landing gear being at a height of 50 ft over the runway threshold For every 10 ft above the standard 50 ft threshold height landing air distance will increase 200 ft 8 Delayed use of deceleration devices Research has found that delayed braking action during the landing rollout was involved in some of the accidents and serious incidents in which slow or delayed crew action was a causal factor The improper use and malfunction of speed brakes wheel brakes and reverse thrust were significant factors in a number of runway excursion landing accidents It is prudent to have a contingency plan if any one deceleration devise does not work A conservative approach is to add 200 ft to the landing distance for every second in excess of 2 seconds to deploy the airplanes deceleration devices 9 Landing with a tailwind Effect of a tailwind on landing distance is significant as this factor determines the landing distance required Given the airplane will land at a particular airspeed independent of the wind the principal effect of a tailwind on operational landing distance is the change in the ground speed at which the airplane touches down A tailwind will increase the landing distance by 21 for the first 10 kts of tailwind 10 Landing on a wet or contaminated runway This was the primary focus for this rulemaking committee Be prepared to determine the landing distance for the conditions at time of arrival which may be very different than the conditions in the before flight weather check The FAA recommends a 15 minimum be added to the calculated landing distance for the conditions at arrival Do not apply this added 15 to any other operational specification rather this 15 margin is prudent safety margin and has proven over time to be of value Compounding effect The end is closer than you think As with most accidents and incidents a chain of events is most common as opposed to a single elemental cause In the Dec 8 2005 incident at MDW there was a delay in deploying deceleration devises SAFO 16008 Jul 26 2016 deals with runway excursions during takeoff Although landing excursions outnumber takeoff excursions by a factor of 4 takeoff excursions are still an issue Runway overruns account for 2 out of 3 takeoff excursions Turboprops account for the highest number of accidents closely followed by turbojets Much of the issue seems to center on incorrect takeoff performance data usually due to last minute load changes and or inadequate checks and balances in data verification Often takeoff performance calculations are made well before engine start If the runway conditions are rapidly deteriorating a procedure to perform a final takeoff analysis should be part of SOPs Mental preparation for an early abort when runway conditions warrant should always be considered when taking the runway for departure Recognition of the problem The ARC discovered that old methods of assessing runway slipperiness were inadequate and have either not prevented or have contributed to runway excursion incidents A major 1 Landing distance From AFM At target landing speed 50 ft at the threshold crossing height dry runway zero wind 0 data provided based on airport elevation density altitude 2 Excess threshold crossing height With each 10 ft increase in threshold crossing height add 200 ft to the landing distance 6 Less than maximum braking Add 20 to landing distance for less than maximum braking 7 Delay to employ deceleration devices For each second beyond 2 seconds add 200 ft to landing distance 8 Add 15 safety margin to the resultant required runway length as recommended by SAFO 06012 1 2 3 5 4 6 7 8 Example 5000 ft available runway The end is closer than you think A graphic example of the compounding effect of multiple errors factors on landing distance An arrival on speed at the correct location and prompt and full use of all deceleration devices is good habit forming practice even on very long runways