This article about Method 1 and Method 2 gives a brief explanation of Methods 1 and 2 in terms of dispatching flights under 14 CFR 121. Here's an excerpt.

FAR 121.191 requires that we dispatch our aircraft on a routing, weight and expected enroute temperature, that complies with a minimum terrain clearance requirement after an engine failure.

It also requires that we have a plan in place that allows a diversion to an alternate airport enroute, following an engine failure and drift down, with a specific terrain clearance if we do not have the performance to continue to the destination.

My question about flights dispatched under Method 2 concerns route changes. In practice, I'm quite sure that pilots operating aircraft with a Method 2 dispatch release deviate from the planned route on the dispatch all the time. Reasons might include a shortcut request to air traffic control or deviations for weather. Weather deviations seem like the most relevant here because they can sometimes be quite significant.

What additional considerations do pilots have when accepting route changes on flights dispatched under Method 2? Couldn't changing the route render the Method 2 calculations irrelevant?

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    $\begingroup$ I think the title needs to be slightly modified... "Method 2" is not really an industry term, but instead something specific to this page's explanation or possibly Jeppeson's flight planning software and/or JetBlue's GOM. In a more generic sense, pilots might deviate from planned routes where terrain clearance was taken into account in the release. Perhaps: "What additional considerations do pilots have when deviating from the planned routing on flights dispatched with terrain clearance requirements?" (or something like that) $\endgroup$ – Jimmy Feb 28 '17 at 5:37
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    $\begingroup$ "Method 1" and "Method 2" are common enough that I'd rather make the question more specific than lose that detail. It's a matter of opinion whether or not they are "industry terms." I believe they are from my conversations with pilots from other US 121 pilots. $\endgroup$ – ryan1618 Mar 1 '17 at 0:10

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