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Thread: POH/Gross Weight question for home built airplanes.

  1. #1

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    POH/Gross Weight question for home built airplanes.

    Reading about Long EZs, I came across a bit about gross weight, which led to this POH: http://roynouguier.free.fr/lezoman.pdf

    On page 30/39 there is a bit about "over-gross operations", which leads me to asking some questions about gross weight in EAB aircraft.

    In the case of this over-gross (1420lb) vs gross (1325lb) weight, which would be considered the gross weight for the purposes of the data plate?

    What testing would be required for weights within the over gross section during Phase 1?

    (And this one is just curiosity) If an owner (that does not hold the repairman cert) wanted to change the gross weight of an aircraft, could it be done, and if so, what would that process be?
    Looking to buy my first airplane, message me if you have a nice trainer or experimental for sale.

  2. #2
    EAA Staff Joda's Avatar
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    Quote Originally Posted by thisadviceisworthles View Post
    Reading about Long EZs, I came across a bit about gross weight, which led to this POH: http://roynouguier.free.fr/lezoman.pdf

    On page 30/39 there is a bit about "over-gross operations", which leads me to asking some questions about gross weight in EAB aircraft.

    In the case of this over-gross (1420lb) vs gross (1325lb) weight, which would be considered the gross weight for the purposes of the data plate?

    What testing would be required for weights within the over gross section during Phase 1?

    (And this one is just curiosity) If an owner (that does not hold the repairman cert) wanted to change the gross weight of an aircraft, could it be done, and if so, what would that process be?

    First, the gross weight is not required to be recorded on the data plate. Even if you have a data plate that has a place for gross weight, do not put it on there. The only items required on the data plate of an experimental aircraft is the builder name (aka "manufacturer"), the aircraft model, and the aircraft serial number. It is not recommended that you put any other info on the data plate.

    The reason is, these three items of information are the only three that will never change. The N number could be changed. The owner could be changed. The builder's address could be changed. And yes, even the gross weight could change.

    Changing the gross weight of an aircraft is a "major change", and would be incorporated in accordance with the aircraft's operating limitations. The operating limitations are issued by the FAA as a part of the aircraft's airworthiness certificate, and must be carried in the aircraft at all times. The operating limitations will contain info on the process for incorporating a major change to that aircraft.

    Which brings us the the original question about operating "over gross weight". The regulations state that the aircraft must be tested to make sure it doesn't have any adverse handling characteristics or performance issues. Any operations desired during phase 2 (normal operations) must be tested in phase 1 (flight test phase). So if the aircraft is tested to 1325, as in your example, it would not be legal to operate the aircraft in phase 2 operations at any weight above 1325 regardless of what it says in the "POH". If you would want to operate the aircraft at 1420, you would have to follow the major change provisions of the operating limitations and test the aircraft at that operating weight in a phase 1 flight test period. Once the major change provisions of the operating limitations are met the aircraft could be returned to phase 2 and operated up to the new gross weight of 1420 lbs.
    Cheers!

    Joe

  3. #3
    Dana's Avatar
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    The gross weight is whatever the builder says it is. A smart builder uses the numbers determined by the designer, anything more and you reduce the limit load factors. The aircraft is supposed to be tested at that gross weight during phase 1.

    If the owner (doesn't have to be the builder, don't need the repairman certificate) wants to change the gross weight, he has to notify the FAA that he's making major change to the aircraft and putting it back in phase 1 The FAA will assign a test area and time (typically 5 hours). You fly out at the new gross weight for the 5 hours, make the appropriate logbook entries, and you're done.

  4. #4
    EAA Staff Joda's Avatar
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    Quote Originally Posted by Dana View Post
    If the owner (doesn't have to be the builder, don't need the repairman certificate) wants to change the gross weight, he has to notify the FAA that he's making major change to the aircraft and putting it back in phase 1 The FAA will assign a test area and time (typically 5 hours). You fly out at the new gross weight for the 5 hours, make the appropriate logbook entries, and you're done.
    True to a point, but you can't make blanket statements about how to incorporate a major change. The operating limitations have changed over the years, so it depends on when the airworthiness certificate was issued as to what the major change procedure will be. For example, operating limitations issued back on the early days (up into the early 70s at least) used to say "A major change invalidates this airworthiness certificate". So if you have those operating limitations, you need to do a recurrent certification in order to incorporate a major change. (Which isn't a bad idea anyway, since you will get the most current version of the operating limitations when you re-certificate the aircraft.)

    Then there was a time where the operating limitations said that you had to contact the cognizant FSDO and receive their response "in writing" before operating after incorporation of a major change. There was even a brief window in the 2000-2001 time frame where you didn't have to contact the FAA at all, and just did appropriate entries in the aircraft records before and after a 5 hour minimum flight test period.

    The current version requires that you contact the cognizant FSDO and receive concurrence on the flight test area you wish to use in order to incorporate the major change. Then you make the appropriate entries in the aircraft records before and after the minimum 5 hour flight test.

    There can be, and probably are, variations of all these procedures depending on the issuing office and inspectors. Which drives home my point about reading the operating limitations of YOUR aircraft. Doesn't matter what anyone else thinks, or what the current policy is. For YOUR aircraft you need to follow the procedure called out in YOUR operating limitations. Don't just assume yours is the same as your buddie's. Read and follow your operating limitations, or if you don't like the ones you have (most likely because they are the older version) have the aircraft re-certificated and get updated ones.
    Cheers!

    Joe

  5. #5
    gbrasch's Avatar
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    I made it a point to put the manufacturers recommended gross weight on the data plate of my RV-9A. Maybe just for liability reasons, I don't really agree with others to arbitrarily just add, say, 50 pounds like I have seen many others do.
    Glenn Brasch
    KRYN Tucson, Arizona
    2013 RV-9A
    Medevac helicopter pilot (Ret)
    EAA member since 1980
    Owner, "Airport Courtesy Cars" website.
    www.airportcourtesycars.com
    Volunteer Mentor www.SoAZTeenAviation.org

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