If one hydraulic pump of an electro-hydraulic steering unit fails, the vessel’s steering c

One function provided by a hydraulic accumulator is to ___.

A.provide an area where air can separate from the oil

B.provide an area to separate solid contaminants from the oil

C.act as an oil and water separator

D.absorb shocks occurring in the system

n be initially and best maintained by using the _____.

A.trick wheel

B.accumulator

C.standby pump

D.telemotor

ne recommended by the manufacturer in a mechanical hydraulic governor, will result in the need to adjust the

A.pilot valve opening

B.compensating needle valve

C.compensating spring tension

D.accumulator spring tension

材料：

At 1800，the hydraulic steering system failed once again．The master realized he would require shore assistance to rectify the problem，and diverted towards Portland using the thruster to steer by．The weather at this time was south-south-west force 5．At about three hours later，the thruster drive unit failed due to a leaking fuel injector pipe on the power unit．This was replaced using the spare carried on board．Immediately following the engine restart，an adjacent fuel line failed causing shut down of the unit．With no fuel line spares available，the thruster power unit could not be used．The failure of this unit，and that of the main hydraulic steering system，left the vessel without any steering capability．

At 2155，with the weather deteriorating and no steering，the master contacted the Portland Coastguard and a“Pan pan”message was broadcast．A tow to Portland Harbor was arranged and she arrived alongside at 0240 the following morning．The subsequent investigation found that the main hydraulic steering system failure was due to a seized shuttle valve in the main hydraulic solenoid valve block．The solenoid valve had been recently overhauled．It was thought that the“O”rings fitted to the shuttle valve were of either the wrong type or a defective one．The valve had seized in such a position that hydraulic pressure by-passed the system preventing use of the hand steering．

问题：

The vessel was steered by thruster because ________ failed．

A.the hydraulic steering system

B.the solenoid valve

C.the thruster driving unit

D.the hand steering

The time that the thruster drive unit failed was ________ hrs．A.1800

B.2100

C.2155

D.0240

When the hydraulic steering system failed，________．A.the hand steering system could still be used

B.the auto steering system could still be used

C.both hand and auto steering system were out of use

D.neither and steering system nor auto steering system was out of use

The real reason that caused the hydraulic steering system to fail was that ________．A.no fuel line spare were available

B.the weather was deteriorating

C.the“O”rings fitted to the shuttle valve were of either the wrong type or a defective one

D.the thruster power unit failed

请帮忙给出每个问题的正确答案和分析，谢谢！

A.PW

B.JET-A/G2

C.PUM/DK

D.WZB/ZDK/AWZB

A．the oil separator

B．the fresh water generator

C．the compressor

D．fire pum

A．the exhaust valves

B．the fuel valves

C．indicator cocks

D．the fuel pum

A．Steering gear and windlass

B．Navigation light and radio power panel

C．Navigation device power box

D．Daily fresh water pum

A.配网PUM

B.配网差动保护

C.高级计量

D.智能配电房

flights and one space walk. But he recalls with special fondness a decidedly earthbound experience in the summer of 1980, when he participated in the NASA-AS-EE Summer Faculty Fellowship Program. Voss, then a science teacher at West Point, was assigned to the Marshall Space Flight Center's propulsion lab in Alabama to analyze why a hydraulic fuel pump seal on the space shuttle was working so well when previous seals had failed. It was a seemingly tiny problem among the vast complexities of running the space program. Yet it was important to NASA because any crack in the seals could have led to destructive results for the astronauts who relied on them.

"I worked a bit with NASA engineers," says Voss, "but I did it mostly by analysis. I used a handheld calculator, not a computer, to do a thermodynamic analysis. "At the end of the summer, he, like the other NASA-ASEE fellows working at Marshall, summarized his findings in a formal presentation and detailed paper. It was a valuable moment for Voss because the ASEE program gave him added understanding of NASA, deepened his desire to fly in space, and intensified his application for astronaut status.

It was not an easy process. Voss was actually passed over when he first applied for the astronaut program in 1978. Over the next nine years he reapplied repeatedly, and was finally accepted in 1987. Since then he has participated in three space missions. The 50-year-old Army officer, who lives in Houston, is now in training for a four-month mission as a crew member on the International Space Station starting in July 2000.

Voss says the ASEE program is wonderful for all involved. "It brings in people from the academic world and gives NASA a special property for a particular period of time. It brings some fresh eyes and fresh ideas to NASA, and establishes link with our colleges and universities," Voss explains. "There's an exchange of information and an exchange of perspectives that is very important."

For the academic side, Voss says, the ASEE program also "brings institutions of higher learning more insight into new technology. We give them an opportunity to work on real-world problems and take it back to the classroom. "

Why was the hydraulic fuel pump seal important for the space shuttle？

A．Because previous seals all failed.

B．Because it was very complex in running the space program.

C．Because great care has to be taken of the hydraulic fuel pump sealing.

D．Because any crack in the seals would cause disastrous results for the astronauts.