The pilot is exercising the altitude flight.

飞行员正在练习高空飞行。

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The aircraft has an unpressurised cabin and four underpowered turboprop engines, making it only suitable for low- to medium-altitude flight.

飞机采用非气密舱和四台动力不足的涡轮螺旋桨发动机，使它仅仅适用于低-中空飞行。

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The tentative design of constant altitude flight solid rocket composed of the sustainer the booster and its simple control method is presented.

介绍了主发动机加助推器和简易控制方法实现固体火箭等高飞行的设计方案。

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It rocketed up to a mere 55, 000 feet before shutting down and gliding back to terra firma, an important first step before a full-altitude flight later this year and planned commercial flights in 2015.

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The altitude is also near the flight limit for some U.S. combat helicopters, officials said.

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On an April 20, 1962 flight achieving an altitude of 207, 000 feet, he held the nose up too long during descent, causing the craft to bounce off the atmosphere back up to 140, 000 feet.

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