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View Full Version : Incident: Ethiopian B738 at Addis Ababa on Aug 26th 2019, runway excursion on landing


sonicbum
27th Aug 2019, 12:49
AVHERALD (http://avherald.com/h?article=4cc0fcf7&opt=0)
An Ethiopian Airlines Boeing 737-800, registration ET-AXI performing flight ET-307 from Nairobi (Kenya) to Addis Ababa (Ethiopia), landed on Addis Ababa's wet runway 07R at about 21:20L (18:20Z) when the aircraft veered right after crossing the displaced threshold runway 25L and came to a stop off the right runway edge. There were no injuries, the aircraft sustained minor if any damage. Emergency services responded, the passengers disembarked onto the runway via mobile stairs.

The occurrence aircraft is still on the ground in Addis Ababa about 15.5 hours after landing.

Position data transmitted by the aircraft's transponder suggest the aircraft touched down at 155 knots over ground about 6920 feet past the displaced runway threshold (landing distance available 11297 feet, thus 4377 feet remaining), crossed the displaced threshold 25L about 3250 feet later, veered right and came to a stop beyond the right runway edge about 3720 feet past the touch down position, about 10,630 feet past the displaced runway threshold 07R and about 670 feet short of the runway end.

Raffles S.A.
27th Aug 2019, 15:32
A 738 can stop in 3720 feet from 155 kts on a wet downhill slope?

My friend answered my question. Landing distance with autobrake 1 under those conditions at MLW is around 3740 meters. Could they possibly stop in 3720 feet, 1/3 of the published landing distance?

Sailvi767
27th Aug 2019, 21:43
Auto brakes 1 is basically no brakes. Reverse thrust would generate the decel rate required for autobrakes 1. You would not expect a crew to use auto brakes after landing long regardless. You would expect full pedal pressure which would be dramatically shorter stopping distance. If the landing touchdown point was as reported a go around was the correct solution.

misd-agin
28th Aug 2019, 00:51
737 HUDís show the de-acceleration rate. At S.L. full reverse and deployed ground spoilers/spoilers generates approx. 2.75 de-acceleration rate at touchdown. It decreases to a de-acceleration rate of approx 2 at 90-100 kts.

You can verify that by using full reverse until you feel the auto brakes starting to engage. Itís normally close to 90 kts.