Stabilized Approach And Flare Are Keys to Avoiding Hard Land(12)

曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

The accident report said that VREF for the airplane’s landing weight was 138 knots and that with wind-correction factors, the proper target approach speed was
150 knots. during the last 10 seconds
of the approach, the airplane’s indicated
airspeed decreased from 143 knots to 130 knots.
All three flight crewmembers said that the touchdown was harder than normal but not one that they would classify as a hard landing. Several flight attendants said that two ceiling panels dislodged
when the airplane “slammed down” onto
the runway. During a postflight inspec-tion of the airplane, the flight engineer found that the lower rear fuselage was damaged. A subsequent maintenance inspection revealed damage, consistent with a tail strike, to the pressure bulkhead and several bell frames and stringers in the aft fuselage.
Cope With Crosswinds

A
dverse wind conditions — crosswinds, tail winds, wind shear, etc. — can cause an ap-proach to become unstabilized. Rapid and large flight-control movements in reaction to gusts increase the risks of a hard landing and of strik-ing a wing tip or an engine nacelle against the runway.33
JAA and FAA transport category airplane cer-tification standards require a demonstration of safe controllability characteristics and handling characteristics during a landing on a dry runway
with a 90-degree crosswind component of at least 20 knots or equal to 0.2 VSO (the airplane’s stall speed or minimum steady flight speed in landing configuration), whichever is greater. The dem-onstration does not have to be conducted with
a crosswind component of more than 25 knots,
however.
Nevertheless, most large jets have demonstrated
crosswind components that are greater than 25 knots. examples include: 33 knots for the a320-100/200; 32 knots for the B-747SP; and 35 knots
for the MD-11.
Demonstrated crosswind components generally are advisory, not limiting. Some aircraft operators prohibit flight crews from conducting a landing if wind conditions exceed the airplane’s demon-strated crosswind component. FAA prohibits air
carrier first officers with fewer than 100 flight
hours in type from landing with a crosswind component of 15 knots or more unless they are flying with a check pilot.34 In the absence of such prohibitions, flight crews can conduct a landing if wind conditions exceed the airplane’s demon-strated crosswind component when they believe it is safe to do so.
Crab or Slip
G
enerally, flight crews use one of two tech-niques to land with a crosswind.
The “crab/de-crab” technique involves establish-ing a wings-level crab angle on final approach
that is sufficient to track the extended runway centerline (Figure 1, page 10). about 100 feet
AGL, downwind rudder is applied to de-crab and align the airplane with the runway center-line, and upwind aileron is applied to prevent drift or to keep the wings level if the airplane has underwing-mounted engines or long wings. This technique results in the airplane touching down simultaneously on both main landing gear with the airplane aligned with the runway centerline.
　
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：Stabilized Approach And Flare Are Keys to Avoiding Hard Land(12)