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As we know, there are no four-engined business/private jets currently in production. Some Dassault Falcon models are actually trijets, but this is not the case. The only four-engined business jet in serial production was Lockheed JetStar line.

I'm wondering, in case of extremely rare emergency event, when 3 out of 4 16.5kN TFE7313 engines shutdown, could JetStar constantly fly on some flight level without loss of altitude using only one engine?

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  • $\begingroup$ I'm pretty sure the answer to this is no. Even most twins can't hold altitude on a single engine. There is an old saying that when you have a multi-engine aircraft with an engine out, the other ones just get you to the crash site faster (or something like that). $\endgroup$
    – Ron Beyer
    Jul 7, 2016 at 16:33
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    $\begingroup$ Possible. But at a very high power setting for that engine and a healthy boot full of rudder to track straight. And your best rate of climb will be anemic, if any at all. $\endgroup$
    – Carlo
    Jul 7, 2016 at 16:55
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    $\begingroup$ @RonBeyer ALL twin jets not only CAN hold altitude single engine, they can climb out on 1 at max t/o weight -- it's a certification requirement. The real answer to this question can only come from the JetStart performance book, but it wouldn't shock me if the answer is, on a cold day with a light load, yes. I could also believe "no" -- but it will take the performance charts to resolve this. A sufficiently light 777 almost certainly CAN hold level flight on 1/2 the rated thrust of 1 engine (1/4 full thrust), so it's not unimaginable that a JetStar might also, under the right conditions. $\endgroup$
    – Ralph J ♦
    Jul 8, 2016 at 2:51
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    $\begingroup$ @RalphJ Complete mind slip on my part, I was thinking of twin pistons. I'm still under the impression of it not being possible to hold altitude on a single engine of four. As you say, twin jets are designed to lose an engine, quad jets are not designed to lose three... $\endgroup$
    – Ron Beyer
    Jul 8, 2016 at 3:36

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I have 3000 hours in jetstar.... The answer is no... It will not fly on one... Two yes and you really don't need that much rudder.. In the simulator with two out I used to put the inboard operating engine at 98% and modulate the outboard engine to control speed/sink doing that it really only needed 1/4 rudder trim

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    $\begingroup$ Thanks for chiming in with actual experience! Hope you stick around to provide more great answers. $\endgroup$
    – FreeMan
    Jul 31, 2016 at 17:42

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