In the approach phase, engine 1 of [Cathay Pacific flight 780](https://en.wikipedia.org/wiki/Cathay_Pacific_Flight_780) got stuck at about 70% N1 and it forced the crew to do an overspeed landing (230knots).

Why didn't they shut it off by turning the fuel pumps off? Is there a backup mechanism if the fuel valve fails like in this scenario?
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From the incident report section 1.1.4:

> 
> a. At 0519 hrs during the descent to a cleared level of FL230, ECAM
>  messages “ENG 1 CTL SYS FAULT” and “ENG 2 STALL” were annunciated
>  within a short period of time. According to the Commander, a light
>  “pop” sound was heard and some “ozone” and “burning” smell was
>  detected shortly before the ECAM message “ENG 2 STALL”
> 
> 
> 

Then later:

> 
> e. At 0530 hrs, when the aircraft was approximately 45 nm southeast
>  from VHHH and was about to level off at 8,000 ft AMSL, ECAM message
>  “ENG 1 STALL” was annunciated.
> 
> 
> 

So now both engines are out, they started the APU and successfully managed to restart #1:

> 
> h. The crew moved the thrust levers to check the engine control but
>  there was no direct response from the engines. The No. 1 engine speed
>  eventually increased to about 74% N1 with the No. 1 thrust lever in
>  the CLB (climb) detent position. The No. 2 engine speed remained at
>  sub-idle about 17% N1, with the No. 2 t hrust lever at the IDLE
>  position.
> 
> 
> 

Engine 2 was out of action, producing no power, engine 1 had failed, but was temporarily working although they couldn't adjust power, if they'd shut that down too they'd have been gliding and probably would have crashed with total loss of life. They didn't have the power to climb and had one shot at landing, so they made damn sure they got it on the runway, not a bad landing considering the circumstances. 

On a humorous note, another example of pilot understatement:

> 
> l. At 0539 hrs, the Commander made another PA advising the passengers
>  of having “small problem with the engines” with small vibrations and
>  requesting them to remain seated and follow the directions from the
>  cabin crew.
> 
> 
>
I could be wrong but reverse thrust from the running engine helped to stop the plane1 as it was approaching at a great speed way over the recommended landing speed, so shutting the running engine off right at approach would have made the plane to overshoot the runway, making the situation worse.

---

1: Source:

> 
> [...] The aircraft then rolled left seven degrees and
>  pitched down to -2.5 degrees at the second touchdown during which, the lower
>  cowling of No. 1 engine contacted the runway surface. Spoilers deployed
>  automatically. **Both engine thrust reversers were selected by the Commander.
>  Only No. 1 engine thrust reverser was deployed successfully and ECAM message
>  “ENG 2 REV FAULT” was annunciated.** Maximum manual braking was
>  applied. ... *[[Accident report](https://www.webcitation.org/6Rk7TGDPW?url=http://www.cad.gov.hk/reports/2%20Final%20Report%20-%20CX%20780%202013%2007%20web%20access%20compliant.pdf), page 26. Engine #1 was the one that was stuck at 74% N1.]*
> 
> 
>