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Many times I read articles on sites like aviaton herald about engine shutdown in fight because of some problem. It's given the problematic engine will be repaired.

Question is about other working engine. For a twin engine jet, for a period of time, it did double work. After landing, does the engine go through some extra inspection and/or maintenance routine because it went through extra responsibility.

I tried using word extra load as I really don't know if engine has any extra load. All I know is aircrafts are designed to operate/land safely even if one engine fails.

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    $\begingroup$ If the engine might have failed because of poor or neglected maintenance procedures, wouldn't it be prudent to check the other one? $\endgroup$ Commented Oct 1, 2023 at 15:41
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    $\begingroup$ A long time ago I knew an amateur pilot who gave me this piece of wisdom: the purpose of the second engine in a twin engine plane is to get you to the scene of the crash. $\endgroup$ Commented Oct 1, 2023 at 16:43
  • $\begingroup$ "Double work": no. $\endgroup$ Commented Oct 2, 2023 at 5:03
  • $\begingroup$ @MarkRansom But that is for small propeller-driven aircraft. Large air transport planes must have stronger engines and often even be ETOPS capable. $\endgroup$ Commented Oct 2, 2023 at 8:22

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After an engine fails in a twin-engine jet transport category airplane the remaining engine is capable of providing the necessary power/performance for the aircraft to continue safely operating for the remainder of the flight at a power setting at or below its maximum design limitations. As a result, the remaining engine would be operating within its design limitations and an "...extra inspection and/or maintenance routine..." should not be necessary.

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    $\begingroup$ I think the OP is asking is because the first engine failed, could this be caused by something outside the engine itself (fuel contamination, poor maintenance, etc), that could impact the other engine? This would warrant checking the other engine, in case it is likely to fail soon $\endgroup$
    – CSM
    Commented Oct 1, 2023 at 19:57
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    $\begingroup$ @CSM Perhaps, but the OP, it seems to me, is asking about "double work" and "extra load" being placed on the working engine. $\endgroup$
    – user22445
    Commented Oct 1, 2023 at 20:02
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    $\begingroup$ There would certainly be an investigation into what caused the engine failure, @CSM, and if it were something like contaminated fuel, I'm sure there'd be checks on the working engine to ensure it's not been damaged by the potential common-failure mode. However, if it was a "simple" part failure (or bird ingestion), then that wouldn't affect the other engine and there'd be no reason to worry about it. $\endgroup$
    – FreeMan
    Commented Oct 2, 2023 at 15:43
  • $\begingroup$ @RTO: Many engines are not rated to be operated for long periods of time at maximum thrust unless they receive more frequent maintenance than would otherwise be required, but some kinds of engine failure that lead to increased drag may make it necessary to operate the remaining engine at maximum power for longer than would otherwise be needed. $\endgroup$
    – supercat
    Commented Oct 2, 2023 at 22:17
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In an engine-out scenario, the remaining engine(s) are operated at a higher power. In itself, this does not require additional checks, just like if the crew was required to make a max-power takeoff versus a lower one.

However, this additional stress may push the remaining engines over operating limits which requires maintenance action. The most typical sign would be engine exhaust gas temperature (EGT) over limits. Typically as an engine ages and it becomes less efficient, it requires more fuel and moves less air, increasing EGT. High EGT is a reliable indicator of wear, and obviously can cause damage itself, e.g. melted parts. The two regimes where engines first hit EGT limits are operation at high powers, and starting.

If an EGT exceedance occurs, this is logged by the avionics and mechanics will action a procedure. Depending on the magnitude (degrees and time), this may mean no action but watching the engine, a borescope inspection, or taking the engine off the wing for overhaul.

Other common exceedances are overthrusting/overboosting, when the primary thrust setting parameter exceeds limits (N1 rotor overspeed, EPR too high). This is rare in modern computer-controlled FADEC engines, as the control loops manage this well, but occurs in older engines. Excess vibration also is a sign of damage, pointing to some physical change internally.

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Just as an integration to the other answers.


Aircraft's engines possess indeed several power ratings.

The value that is normally found on the price tag is the so-called Maximum Continuous Power MCP i.e. the maximum power that the engine can output for prolonged periods of time.

Alongside this value there's for example the Maximum Take-off Power MTP, which is a power level that can be held for no more than 5 min at sea level. In extreme cases the engine can be pushed to its Transient Power which can be held for no more than 20 sec (the actual value depends on the manufacturer).

Should any of these limitations be overcome, an extraordinary maintenance/overhaul is necessary, which might even end up with the engine being scrapped.

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