Appendix 3 TABLE 3-3. ALL FACTORS CUMULATIVE LANDING DISTANCE EXAMPLE
STABILIZED APPROACH AND TIMELY DECELERATION
1. Available runway length. 5,000 ft
2. Per AFM, Dry runway Unfactored AFM landing distance for density altitude & lightest landing gross weight. 3,000 ft
3. Runway Slope -1%: Add 10% of landing distance per 1% downhill slope, i.e., 1% downhill slope adds 10% to the landing distance.
4. Excessive airspeed at 50-ft landing threshold, landing distance increase: For each 10% increase in landing speed greater than the AFM, add 20% landing distance or:
Example: 10% fast (3,300 × .20 = 660 ft).
5. Tailwind Condition: Add 21% to landing distance for each 10 kts in tailwind.
Example: 10 kt Tailwind .21 × 3,960 = 832 ft.
6. Extended Flare Add 200 ft/sec flare time:
Results in a 200 ft/sec additive (2 × 200 = 400 ft). 0
7. Excess 50-ft height – Add 200 ft to the landing distance for each 10 ft above 50 ft. Example: 10-ft excess. 0
8. MEL/CDL additions: Any additions caused by minimum equipment list (MEL)/Configuration Deviation List (CDL) requirements No MEL/CDL additive 0 ft.
9. Sum of before landing items 2 through 8 added 2,392 ft equals 80% greater than 3,000 ft. 3,300 ft
10. Deceleration devices, 3 second deployment time.
(1 second more than the 2 second max) add 200 ft per each second greater than 2 seconds.
Add 200 ft or use AFM data if available.
11. Less than maximum braking add 20% or use AFM data if available. 0
12. Wet Runway SAFO Safety Margin.
If wet, add 15% of line 9 or use AFM data if available .15 × 5,392 = 809 ft.
495 ft
13. After Landing factors Lines 10 - 13 added 495 ft, leaving 1,210 ft runway remaining after the 15% safety margin.
Reduced landing distance: 3,927 ft.
Cumulative landing distance within 66% of available runway.
3,790 ft NOTE: In a stabilized approach, the proficient pilot receives an accurate runway condition report, chooses to land on a runway with a favorable wind for landing, and adds a safety margin, which results in stopping within the landing distance available.
Appendix 4 APPENDIX 4. UNSTABILIZED APPROACH CASE STUDY You, the first officer, obtained automated terminal information service (ATIS) information during the descent that indicated strong westerly winds on the ground and field elevation of approximately 800 feet (ft) mean sea level (MSL). Because of terrain, the most common approach to the landing runway is via the instrument landing system (ILS) approach to another runway, and then to perform a circle-to-land maneuver to the landing runway.
(a) Air traffic control (ATC) then advises you of updates to the ATIS and also to expect a straight-in approach. You have approximately 5 minutes to prepare for landing on the new runway. Without performing a completely new approach briefing, you prepare for the change in runway by confirming your previously planned flap setting of 40 degrees, with a reference landing airspeed (VREF) of 138 knots (kts). Given that the airplane is flying the ATC assigned, heading and descending steadily with the autopilot engaged, routine communications with ATC almost entirely consume the short time available to prepare the approach.
(b) The newly assigned runway is relatively short and will have a tailwind; however, the landing distance is adequate, but provides little margin for error. While you are obtaining the new ATIS (indicating a tailwind for landing, but within the airplane’s tailwind limit), the captain receives and acknowledges an ATC instruction to maintain 230 kts or more until advised, with vectors to a base leg, and to follow another airplane to intercept the final approach path. Then, when ATC clears your airplane for a visual approach to the runway, the airplane is at 230 kts, at 5,000 ft MSL, and almost 10 miles away from the runway. Noting that the airport’s elevation is approximately 800 ft MSL, the captain must both slow the airplane and descend relatively quickly to make the landing, while configuring the airplane for landing.
(1) Do You Continue With the Approach? ATC positions the airplane high and fast close to the runway, and now you face the difficult task of establishing a stabilized approach.
Alternative options include either extending the approach path in cooperation with ATC or abandoning the approach. However, 1 minute after ATC clears the airplane for the approach, you perform the first configuration change to get the airplane below 225 kts (the maximum speed to extend flaps to 5 degrees). The airplane is now descending to 3,000 ft, slowing through 225 kts, and slightly overshooting the final approach course on autopilot.
(2) What Would Your Landing Strategy Be? The captain then disconnects the autopilot and brings the airplane back on course, ordering gear extension and successive flap extensions, while maintaining 3,000 ft until 3 miles from the threshold. The captain then commands flaps 40 while the airplane is above 180 kts. (Maximum speed for flaps 40 is well below this speed.) The airplane then slows to 180 kts, and the captain is flying the approach at more than twice the normal 3-degree gradient to the runway in his or her efforts to touch down just beyond the runway threshold. When the airplane passes below 1,200 ft above ground level (AGL), and its descent rate increases through 2,900 ft/minute, the ground proximity warning system (GPWS) “sink rate” warning starts to sound continuously, later followed by the more stringent “whoop, whoop, pull up” warning.
(3) What is Your Reaction? When the airplane reaches 1,000 ft above airport elevation, its airspeed has increased to almost 200 kts with a 14-knot tailwind, and it is descending at more Page 1
Appendix 4 than 2,600 ft/minute. When descending through 500 ft, 16 seconds from touchdown, speed is unchanged and descent rate is almost 2,000 ft/minute. You miss the 500 ft required callout as you are also concerned about the airplane that has landed ahead and has not yet cleared the runway. Despite all of this, the airplane continues at a steep gradient greater than 3 degrees until the captain begins the flare for landing at approximately 150 ft AGL. Although he manages to land the airplane within the normal TDZ, he has not been able to slow the airplane while descending at that angle. Despite the engines remaining at idle, the airplane is flying on average some 45 kts faster than the target speed throughout the final approach and landing. The airplane touches down at a speed of 182 kts, with a 6-knot tailwind, some 2,150 ft beyond the runway threshold with approximately 3,900 ft of runway remaining. The captain does not apply and hold maximum brake pressure (as it was the airline’s policy to use manual braking rather than autobraking during landing rollouts), and uses reverse thrust. However, he is unable to stop the airplane on the runway, and the airplane overruns the runway.
(4) Lesson Learned. The lesson learned is that flying a stabilized approach is critical for safety, regardless of whether one is flying an airliner or a light airplane. Always fly per company procedures, use the manufacturer’s AFM/POH landing performance for the current landing conditions, exercise sound aeronautical decision-making (ADM), and ensure the following:
(a) The airplane is on the correct flight path.
(b) Only small changes in heading/pitch are necessary to maintain the correct flight path.
(c) For large airplanes, the airspeed is not faster than VREF (threshold crossing speed) plus 5 kts indicated speed, or as stated in the SOP for windy conditions. Do not fly slower than VREF. For small airplanes, after aligning with the runway, fly the AFM/POH recommended approach airspeed, and adjust airspeed for windy conditions. In the absence of a manufacturer’s recommended approach airspeed, use 1.3×VSO (stall speed or minimum stead flight speed at which the airplane is controllable in the landing configuration), and use flaps per the wind conditions, or as recommended by the manufacturer to ensure positive lateral airplane control during the flare to touch down. (Refer to the current edition of FAA-H-8083-3, Airplane Flying Handbook, for more information.)
(d) The airplane is in the correct landing configuration.
(e) Power setting is appropriate for the airplane configuration and is not below the minimum power for the approach as defined by the operating manual; and the crew has conducted all briefings and checklists.