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What is the legality of removing my step and patching the resulting hole?


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There are two places to look for guidance on what is a "major alteration", and if an alteration doesn't qualify as a major alteration (and therefore require either a 337 or STC), it is by definition a minor alteration and can be done with a logbook entry by a suitably qualified mechanic or repairman.

The definition of a "major alteration" is in FAR 1.1 (definitions):

_________

"Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.

Major repair means a repair:

(1) That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations."
______


The other place is FAR 43 Appendix A part (a) which has a list of specific alterations that must be considered major alterations.   There is a list of major repairs in part (b), and the non-comprehensive list of "preventive maintenance" items in part (c).

If an alteration doesn't fall under the "major alteration" regulations, it doesn't need to be treated as one.  I think removing the step does not qualify as a "major alteration", especially since the factory shipped airplanes both with and without the step under the same TCDS with the same POH.

As always, though, your IA's opinion is the one that matters.

Edited by EricJ
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Le 21/02/2021 à 15:43, N201MKTurbo a dit:

Cela ne fonctionnera pas!

Lorsque vous augmentez la pression du collecteur, vous perdez le vide du collecteur. À plein régime, il n'y a pas de vide du collecteur et votre pas chutera.

Les voitures peuvent utiliser le vide pour les freins et les actionneurs, car elles n'existaient que rarement à des réglages de puissance élevée et la plupart ont des réservoirs à vide pour stocker le vide au cas où.    

Directional, attitude indicator and turn coordinator are instruments mounted in "open" vacuum circuit, that is to say having at the other end an intake filter with a flow rate and a regulated vacuum. For them, the vacuum is associated with a large air flow, in fact the failure of the hoses can lead to a degradation of the power but also the mixing ratio, this is what motivates the use of a suitable auxiliary pump. The "step retract" is an exception in that it is a closed system, like your intake manifold pressure gauge or the modulator of your old GM automatic gearbox on a car. Once the vacuum pressure is established and the step retracted, there is no more airflow. The servo step hose is a 1/4 "ID Polyflo, but the intake manifold can be small in diameter, calibrated to not interfere with the metering of the carbured mixture and carried out on a spacer mounted between the intake manifold and the Bendix RSAD fuel metering unit. There, the 4 cylinders are concerned and the failure hose can be corrected by the mixture control. At the moment, everything is a minor amendment submitted to the authority, which is unlikely to be approved because, as in your case, the bureaucrats do not take into account the technique. And of course, out of the question for me to question the certificate of my F.

Edited by Raymond J
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JR’s post didn’t get the full translation it usually gets...

@Raymond J

Directional, attitude indicator and turn coordinator are instruments mounted in an "open" vacuum circuit, that is to say comprising at the other end an intake filter with a flow rate and a regulated vacuum. For them, depression is associated with a high air flow, in fact the failure of the hoses can lead to a degradation of the power but also of the mixing ratio, this is what motivates the use of a suitable auxiliary pump. . The "no retraction" is an exception in that it is a closed system, like your intake manifold gauge or the modulator in your old GM automatic transmission on a car. Once the vacuum pressure is established and the rate is increased, there is no more air flow. The step pipe is a 1/4 "ID polyflo, but the sample on the intake manifold can be small in diameter, calibrated not to interfere with the metering of the fuel mixture and carried out on a spacer mounted between the manifold Bendix RSAD intake and fuel metering unit. There all 4 cylinders are affected and the failure can be corrected by mixing control. At the moment everything is a minor amendment submitted to the authority, which is unlikely to be approved because, as in your case, the bureaucrats do not take into consideration the technique.And of course, out of the question for me to question the certificate of my F.

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On 2/20/2021 at 9:01 AM, EricJ said:

I think every Mooney since and including the J model has fixed steps, so apparently not that much. 

Do any since the J have retractable steps?

According to the IPC, steps (fixed only) were an option on the M20J and K. I haven’t looked at later models. 
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Just now, PT20J said:

According to the IPC, steps (fixed only) were an option on the M20J and K. I haven’t looked at later models. 
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I tried to sell Rob @takair on the idea of designing retractable steps for Long Bodies...

@apenney I believe posted a pic of the aerodynamic step earlier today... in another thread (power supply).

Best regards,

-a-

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