Stabilized Approach And Flare Are Keys to Avoiding Hard Land(7)

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

during the initial touchdown in Malawi. The data were not available to the flight crew or the SMM. After the accident, the airline programmed the airborne communications addressing and report-ing system equipment aboard all airplanes in the fleet to provide printouts for the flight crew of vertical accelerations of 1.8 g or more recorded during touchdown.
Based on the accident investigation, AAIB recom-mended that the U.K. Civil Aviation Authority
(Caa) consider “methods for quantifying the
severity of landings based on aircraft parameters recorded at touchdown” to aid flight crews in deter-mining the need for hard-landing inspections.
The recommendation was not accepted. In re-sponse, the U.K. CAA said, “Reliance on flight crew judgment is the widely accepted and proven method of determining whether a hard landing has occurred. In the subject incident, the flight crew identified correctly that a hard landing had occurred and called properly for a hard landing inspection. The [CAA] therefore believes that mandating the fit-ment of equipment that would allow frequent access to flight recorder data which would aid flight crew judgment that a hard landing has occurred is not justi-
”21
fied.

Backup Data Help Identify Problems

I
n an ASRS report, the first officer of a Douglas DC-9 freighter said that his company was check-ing recorded flight data to determine whether he had been involved in an unreported hard landing in the airplane.
“No landing I was involved in [with] this aircraft
could be reasonably classified as ‘hard,’” the first
officer said. “[My company] does not define ‘hard landing’ in their general ops [operations] manual or aircraft ops manual, nor do they train their [flight crews] in recognition or reporting of same. I am further concerned that [the company] is removing the aircraft’s flight data recorder to investigate this matter. The flight data recorder does not appear to be designed for recording
landing quality.”22

Airbus and Boeing publish vertical-acceleration
“thresholds” that, when recorded by flight-data-
monitoring equipment, should prompt a hard-landing conditional-maintenance inspection.
Airbus AMMs recommend that a hard-landing inspection be performed when the flight crew reports a hard landing and the digital flight data
recorder (dFdR), or equivalent data-monitoring
unit, indicates that the vertical speed on touchdown exceeded 10 feet per second and/or vertical accel-eration exceeded a specific value, based on airplane
type and landing weight. The vertical-acceleration
threshold for an a340-300, for example, is 1.75 g at less than maximum landing weight.23

The vertical-acceleration thresholds in Boeing
aMMs vary from 1.8 g for the B-747 models to
2.2 g for the B-737 models (when recorded by dFdRs that record 16 samples per second; differ-ent values are published for dFdRs with different sampling rates).24
　
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(7)