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?
['https://aviation.stackexchange.com/questions/59303', 'https://aviation.stackexchange.com', 'https://aviation.stackexchange.com/users/36788/']
You can find the [full incident report here](https://www.webcitation.org/6Rk7TGDPW?url=http://www.cad.gov.hk/reports/2%20Final%20Report%20-%20CX%20780%202013%2007%20web%20access%20compliant.pdf) and this topic is touched upon briefly, but in short they had little to no time to entertain any other options but a full speed landing.

> 
> It was not until the aircraft [was] on the final descent for landing that
>  the Commander realised they could not reduce the thrust on the number
>  1 engine. The speed was not controllable and from that point, there
>  was no time for the crew to consider other strategy nor procedure to
>  cope with such emergency situation.
> 
> 
> 

and more in the conclusion section... 

> 
> **t.** At that stage, there was no time for the flight crew to consider other
>  strategy nor procedure to cope with such emergency situation. The
>  flight crew concentrated on flying the aircraft for a safe landing.
> 
> 
> 

First off, the engine was throwing errors throughout the flight and they were talking to the maintenance team at other points. Ultimately, the proper steps were taken and everything was done by the book. They were prepared for an engine-out landing. When you have a runaway engine malfunction (or throttle stuck at full) shutting down prior to landing *may* not be the right decision if the running engine provides no immediate safety risk. If you shut down a problematic engine in flight you run the serious risk of not being able to get it started again.

Considering that most airports have a bit (or a lot) of extra runway, [EMAS systems](https://en.wikipedia.org/wiki/Engineered_materials_arrestor_system) and often land at the end of the runway, coming in overspeed and burning through your tires and brakes may be safer than cutting the engine and potentially falling short of the runway.
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.
> 
> 
>