The aircraft had reached its cruising altitude of about 39,000 feet.

那架飞机已经达到了大约三万九千英尺的巡航高度。

This height is also the frequent cruising altitude of commercial airliners.

这一高度也是商务航线的常用巡航高度。

According to a Boeing analysis, only 9 percent of fatal accidents occur at cruising altitude.

根据一份波音公司的分析，只有9%的致命事故发生在巡航高度。

Captain: This is Captain Browning and we 're at our cruising altitude of approximately 35,000 feet.

机长：我是布朗宁机长，我们正在大约三万五千英尺的巡航高度飞行。

Captain: : This is Captain Browning and we 're at our cruising altitude of approximately 35,000 feet.

机长：我是布朗宁机长，我们正在大约三万五千英尺的巡航高度飞行。