WA85
Well Known Member
I am hi-jacking Captain Avgas's thread and trying to re-focus the conversation to the topic I think everyone is trying to address - avoiding a catastrophic accident resulting in the death of one of our fellow RV pilots.
Disclaimer - I built a very imperfect RV-8 and I have several of the well known quality issues / errors that I wished I would have learned about when I was building my RV-8 (firewall penetration's with poor fire-proofing, my canopy has 4 cracks in it, I didn't prime the a few parts, my avionics wiring isn't perfect) and I can't claim to be a perfect mechanic either.
However I think what many (Vic, Dan, Walt, Bob, Sam) on this forum are trying achieve, is to point out repetitive quality issues that can lead to a catastrophic outcome.
Instead of trying to define what is acceptable "quality", maybe another way to look at this issue is how does the "defect / quality issue", affect the safety margin and the consequences of the defect / quality issue, which could lead to a catastrophic outcome.
There FAA uses FARs (i.e. 23, 25, 27, 29 etc) to try to encourage aircraft manufacture's to design and build aircraft with known factors of safety and safety margins for safe operation of aircraft.
FAA TSO's are another form of known factors of safety and safety margins for safe operation of avionics.
The venerable FAA AC43-13 is a form of known factors of safety and safety margins for inspection and repair of aircraft and systems.
The DoD has Mil-Hdbk-517 which is used to establish equivalent levels of known factors of safety and safety margins for safe operation of aircraft.
The FAA uses a myriad of processes to establish and maintain safety margins for the inspection, maintenance and repair of "certified aircraft".
A&Ps, IA's, Part 145 R-P are supposed to be trained to follow safe maintenance process and use approved parts and procedures.
Often times we see fellow forum members pointing to these very same requirements as a basis for they think is "acceptable quality".
In the EAB world, very few of these "safety margins / requirements" exist, but that is the nature of beast and some people love the freedom to do that they want.
There are routine examples of "doing what we want" in this forum. Some are brilliant ideas, some are foolish.
Who determines what is brilliant or foolish, this seems to be where the emotional rub seems to be.
Those of use who have careers in aviation safety / airworthiness / engineering see things on this thread that scare us and as professionals, we speak up, often to severe criticism.
Maybe a better way to for the aviation safety / airworthiness / engineering experts on the forum to express their concerns is to explain the loss of "safety margin" and the potential outcomes.
One of the great popcorn topics is installing the GPS / navigator antenna under the engine cowling.
Yes, it will and does work.
However, if you read the fine print for the installation of GPS antenna, it does not approve the installation of he GPS antenna in the operating environment under the engine cowling.
Yes, it will work, but have you looked at the loss of safety margin that you created by doing this?
Did you do environmental testing above and beyond what Garmin has done?
Its likely you copied someone else's installation found on the interweb.
During subsequent real world IFR operations in the NAS, you are now betting your life, and those of others, (especially if you are RNAV only) by your decision to install the GPS antenna in an unapproved location...but it works...until it doesn't and you become and accident.
Why is installing the GPS antenna in an unapproved environment a safety issue? If you think about it, that GPS antenna may be the sole piece of equipment that is providing differential GPS signal to provide the required performance to you navigator / auto-pilot to fly an LPV approach to minimums. It also might be the sole position source for your ADSB out data.
Both are safety critical functions, with a single point of failure at the GPS antenna, that could lead to a catastrophic outcome (erroneous GPS position leads to splat with the ground or another aircraft).
There are host of other topics to debate, but maybe the best way to work through these is issue is for every builder and owner operator to ask themselves if their maintenance, inspection or repair actions reduce the safety margins of their aircraft and how they will possibly affect a catastrophic outcome to themselves and others.
Okay , I am out of popcorn.
As a side note, I have found several issue on my own aircraft that I think lack sufficient safety margin and I am working to resolve them. My firewall penetrations are lousy, I need to fire proof them. My canopy has too may cracks now, its structural integrity is questionable...I have new canopy in the works.
Disclaimer - I built a very imperfect RV-8 and I have several of the well known quality issues / errors that I wished I would have learned about when I was building my RV-8 (firewall penetration's with poor fire-proofing, my canopy has 4 cracks in it, I didn't prime the a few parts, my avionics wiring isn't perfect) and I can't claim to be a perfect mechanic either.
However I think what many (Vic, Dan, Walt, Bob, Sam) on this forum are trying achieve, is to point out repetitive quality issues that can lead to a catastrophic outcome.
Instead of trying to define what is acceptable "quality", maybe another way to look at this issue is how does the "defect / quality issue", affect the safety margin and the consequences of the defect / quality issue, which could lead to a catastrophic outcome.
There FAA uses FARs (i.e. 23, 25, 27, 29 etc) to try to encourage aircraft manufacture's to design and build aircraft with known factors of safety and safety margins for safe operation of aircraft.
FAA TSO's are another form of known factors of safety and safety margins for safe operation of avionics.
The venerable FAA AC43-13 is a form of known factors of safety and safety margins for inspection and repair of aircraft and systems.
The DoD has Mil-Hdbk-517 which is used to establish equivalent levels of known factors of safety and safety margins for safe operation of aircraft.
The FAA uses a myriad of processes to establish and maintain safety margins for the inspection, maintenance and repair of "certified aircraft".
A&Ps, IA's, Part 145 R-P are supposed to be trained to follow safe maintenance process and use approved parts and procedures.
Often times we see fellow forum members pointing to these very same requirements as a basis for they think is "acceptable quality".
In the EAB world, very few of these "safety margins / requirements" exist, but that is the nature of beast and some people love the freedom to do that they want.
There are routine examples of "doing what we want" in this forum. Some are brilliant ideas, some are foolish.
Who determines what is brilliant or foolish, this seems to be where the emotional rub seems to be.
Those of use who have careers in aviation safety / airworthiness / engineering see things on this thread that scare us and as professionals, we speak up, often to severe criticism.
Maybe a better way to for the aviation safety / airworthiness / engineering experts on the forum to express their concerns is to explain the loss of "safety margin" and the potential outcomes.
One of the great popcorn topics is installing the GPS / navigator antenna under the engine cowling.
Yes, it will and does work.
However, if you read the fine print for the installation of GPS antenna, it does not approve the installation of he GPS antenna in the operating environment under the engine cowling.
Yes, it will work, but have you looked at the loss of safety margin that you created by doing this?
Did you do environmental testing above and beyond what Garmin has done?
Its likely you copied someone else's installation found on the interweb.
During subsequent real world IFR operations in the NAS, you are now betting your life, and those of others, (especially if you are RNAV only) by your decision to install the GPS antenna in an unapproved location...but it works...until it doesn't and you become and accident.
Why is installing the GPS antenna in an unapproved environment a safety issue? If you think about it, that GPS antenna may be the sole piece of equipment that is providing differential GPS signal to provide the required performance to you navigator / auto-pilot to fly an LPV approach to minimums. It also might be the sole position source for your ADSB out data.
Both are safety critical functions, with a single point of failure at the GPS antenna, that could lead to a catastrophic outcome (erroneous GPS position leads to splat with the ground or another aircraft).
There are host of other topics to debate, but maybe the best way to work through these is issue is for every builder and owner operator to ask themselves if their maintenance, inspection or repair actions reduce the safety margins of their aircraft and how they will possibly affect a catastrophic outcome to themselves and others.
Okay , I am out of popcorn.
As a side note, I have found several issue on my own aircraft that I think lack sufficient safety margin and I am working to resolve them. My firewall penetrations are lousy, I need to fire proof them. My canopy has too may cracks now, its structural integrity is questionable...I have new canopy in the works.