Ruder Balance Tailbeacon on PA-28-140

brien23

brien23

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How many balance the ruder after installing a tailbeacon on a Piper PA-28-140. The installation instructions say to comply with the manufacture requirements and Piper does require rudder balancing. How can you sign off the 337 without re balancing the ruder to make sure it is within limits, even if it is within one gram of weight of the old light. Also seems like people forget to add it to the equipment list.
 
brien23 said:
How many balance the ruder after installing a tailbeacon on a Piper PA-28-140. The installation instructions say to comply with the manufacture requirements and Piper does require rudder balancing. How can you sign off the 337 without re balancing the ruder to make sure it is within limits, even if it is within one gram of weight of the old light. Also seems like people forget to add it to the equipment list.
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I wouldn’t without rebalancing. Too much liability dinking with a balanced flight control and leaving that unknown. Some flight controls have very narrow balance limits.

that’s like mounting a new engine and RTS without ever running the thing.
 
Having painted my airplane 4 years ago, and saving the data, all I needed to do was a quick calculation to find that the balance was well within parameter.
 
Oh, please. The difference in my Warrior II between the stock Grimes taillight and the TailBeacon was 14 grams. That's a gram less than the weight of 3 US nickels. My rudder has a 4 pound (1816 g) counterweight. The Warrior has flown as well as ever.

If anyone has heard of a rudder balance that was functionally required after TailBeacon installation, please post.
 
Domenick said:
Oh, please... was functionally required after TailBeacon installation, please post.
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FWIW: I could be wrong, but I believe the OP was commenting from a maintenance standpoint that not all installers are performing/noting the required steps for the approved installation, e.g., re-balance, equipment list update. Whether the re-balance is "functionally required" is a moot point if the installation /OEM instructions require it.
 
Bell206 said:
FWIW: I could be wrong, but I believe the OP was commenting from a maintenance standpoint that not all installers are performing/noting the required steps for the approved installation, e.g., re-balance, equipment list update. Whether the re-balance is "functionally required" is a moot point if the installation /OEM instructions require it.
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https://uavionix.com/downloads/tail...Installation-Manual-UAV-1002514-001-Rev-B.pdf

"If installed on a moving control surface, specific attention must be paid to proper balance. Refer to the Manufacturer's Service Manual to determine if balancing is required and for balancing instructions."

= I won't be doing them without balancing them, the sticky part will be when someone finds them out of limits before the mod is done, either from repairs, repainting, replacement of plastic tip caps or other.
 
Domenick said:
Oh, please. The difference in my Warrior II between the stock Grimes taillight and the TailBeacon was 14 grams. That's a gram less than the weight of 3 US nickels. My rudder has a 4 pound (1816 g) counterweight. The Warrior has flown as well as ever.

If anyone has heard of a rudder balance that was functionally required after TailBeacon installation, please post.
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There are many things that manufacturers recommend, or even require, that your plane may fly happily without. But if something happens, who would get the blame? Maybe the last person to touch whatever item; you can be sure that the NTSB will find it, even if it's not germane.
 
bnt83 said:
...I won't be doing them without balancing them, the sticky part will be when someone finds them out of limits before the mod is done, either from repairs, repainting, replacement of plastic tip caps or other.
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As an A&P-IA that is your decision and I respect it.
However, you should warn your customers that the re-balance will likely double, triple, or quadruple your cost of installation, bring the plane down for a more extended period, and no offense intended, but raises the risk of maintenance-induced failure of a critical control system.
 
Domenick said:
However, you should warn your customers that the re-balance will likely double, triple, or quadruple your cost of installation, bring the plane down for a more extended period, and no offense intended, but raises the risk of maintenance-induced failure of a critical control system.
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Curious. Are you saying it's appropriate to skip an FAA-approved mx procedure step because of cost, downtime, and induced errors?
 
as stated, the re-balance is required to be airworthy.
 
Domenick said:
As an A&P-IA that is your decision and I respect it.
However, you should warn your customers that the re-balance will likely double, triple, or quadruple your cost of installation, bring the plane down for a more extended period, and no offense intended, but raises the risk of maintenance-induced failure of a critical control system.
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the cost of FAA compliance is never a consideration.
 
Clearly there must be some lower limit on the amount of weight which matters. Would adding a microgram require rebalancing?
 
PeterNSteinmetz said:
Clearly there must be some lower limit on the amount of weight which matters. Would adding a microgram require rebalancing?
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At some point, yes. Otherwise you could just add weight 1mcg at a time up to some ridiculous amount and never have to rebalance.

Legally, if the install procedures say rebalancing is required, then rebalancing is required to be legal, regardless of the net gain, loss, or neutral.

Physically, it's not just the weight, it's the weight distribution. The Tailbeacon is probably a wash but e.g. stripping and repainting with no net weight gain or loss can still change the balance.

Nauga,
who can play argumentum ad absurdum too
 
How accurate is the rebalancing? I can see how it would take some effort to word a more accurate regulation which might conform with the physical limits. So easier to just say any change requires a rebalance...
 
The light is typically as far from the hingline as physically possible correct?

Tiny changes in weight at a long arm = big moment changes.
 
You can't put a paint stripe on a balanced surface without checking it again.

Probably the best argument for installing one of the other options in cases like the mighty Native American
 
For those who would not balance the rudder would you at least add the tail beacon to the equipment list with the weight of 70 grams and arm.
 
brien23 said:
For those who would not balance the rudder would you at least add the tail beacon to the equipment list with the weight of 70 grams and arm.
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Pretty sure 0.15 pounds is going to be considered “negligible”.
 
Salty said:
Pretty sure 0.15 pounds is going to be considered “negligible”.
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The weight will be negligible for the W&B record but normally there is a place to record the item's weight and arm (location) on the Equipment List.
 
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Salty said:
Pretty sure 0.15 pounds is going to be considered “negligible”.
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Not really, the control (ruder) is the factor to consider. not the total weight of the aircraft.
The aircraft structural manual applies, if the STC does not dictate
 
In my case, the tailbeacon was <1/4oz more than the origional light. That little bit of weight was enough to change the moment, but it is still well within parameter set by the mx manual. never had to remove the rudder, as the w&b for that control surface had been recorded some years before, with no change since.
 
bluerooster said:
... it is still well within parameter set by the mx manual. never had to remove the rudder, as the w&b for that control surface had been recorded some years before, with no change since.
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Where was that recorded? My Warrior was painted back in 1997 and the logbook entry simply says, "Controls removed and replaced, balance checked, found to be within tolerance."

There is nothing on the paint job in the W&B section of the POH.
 
Domenick said:
Where was that recorded? My Warrior was painted back in 1997 and the logbook entry simply says, "Controls removed and replaced, balance checked, found to be within tolerance."

There is nothing on the paint job in the W&B section of the POH.
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I made a note, and keep it with the logs. Just because I'm anal about such things.
 
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