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When I file a flight plan I can file under either IFR or VFR flight rules. However, the Lockheed Martin Flight Services website has the following options in addition to IFR/VFR:

  1. MVFR
  2. MIFR
  3. YFR
  4. ZFR

1 and 2 are only available for US domestic flight plans; 3 and 4 are only available for ICAO plans. What are all these options and when should I use them?

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  • $\begingroup$ I'm pretty sure Y and Z are VFR-to-IFR and IFR-to-VFR flight plans, I can never remember which is which though. $\endgroup$ – falstro Dec 29 '14 at 21:46
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    $\begingroup$ @CGCampbell It's actually explained on the LMFS website, I just hadn't noticed that the "flight plan" heading was also a link... $\endgroup$ – Pondlife Dec 30 '14 at 15:36
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    $\begingroup$ @Pondlife Aha! I see that now. Excellent discovery. Odd how they use Military VFR, contra to the well-known (and potentially misunderstood as well) defined use of MVFR. $\endgroup$ – CGCampbell Dec 30 '14 at 16:15
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According to the tooltips on the Lockheed Martin site, the flight rules are:

  • MVFR - Military VFR; restricted to military flights
  • MIFR - Military IFR; restricted to military flights
  • YFR - Initially operated under IFR, followed by one or more changes of flight rules
  • ZFR - Initially operated under VFR, followed by one or more changes of flight rules

There's very little information on MVFR and MIFR flight plans that I could find, but the FAA's FSS procedures do include specific actions that are required when receiving a military flight plan (section 6-4-7).

YFR and ZFR are ICAO rules; the FAA calls combined VFR/IFR flight plans composite flight plans (see section 5-1-7 in the AIM) and on a US domestic composite flight plan both VFR and IFR should be checked. Interestingly, the Lockheed Martin site doesn't allow that.

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  • $\begingroup$ On the off chance someone stumbles upon to this years later and is interested in knowing more on the military flight plans... I was a civilian ATC in a few facilities handling a lot of military traffic. The military flight plans we received were largely the same, with a few exceptions. One instance in which I can see FS wanting to be told up front that it is MVFR or MIFR is if they are using a stereo route - a commonly used, set route that is coded for brevity in clearances. For example, ROUTE1 could represent ABC-DEF-GHI. There are a few other differences, but that's one informed guess. $\endgroup$ – Aluminum Showers Jun 28 at 4:12
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  • MVFR: Minimum/Marginal Visual Flight Rules
    This refers to the general weather conditions pilots can expect at the surface. MVFR criteria means a ceiling between 1,000 and 3,000 feet and/or 3 to 5 miles visibility.1, 2

  • YFR
    Flight initially being IFR then going VFR3
    ...or...
    Flights that will initially will be operated under IFR, followed by one or more changes of flight rules.4

  • ZFR
    Flight initially being VFR then going IFR3
    ...or...
    Flights that will initially will be operated under VFR, followed by one or more changes of flight rules.4

  • MIFR: Multi-engine IFR5


1: NOAA National Weather Service

2: YahooAnswer

3: PilotsOfAmerica

4: ForeFlight

5: Canadian Fight Center

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    $\begingroup$ You're correct about the normal meaning of those acronyms, but that's not what they mean in the context of this question. $\endgroup$ – reirab Dec 30 '14 at 20:27
  • $\begingroup$ @reirab Thanks for the downvote. I already know the context of the question and have talked with the OP about doing more research. Please post an answer with what they mean in the context of this question and I'll delete mine. $\endgroup$ – Farhan Dec 30 '14 at 20:31
  • $\begingroup$ There's already one above. $\endgroup$ – reirab Dec 30 '14 at 20:32

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