Homebuilt airworthiness standards

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torquey401
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Re: Homebuilt airworthiness standards

Post by torquey401 »

"it seems solid, and because i'm allowed to say so, I deem it safe! Let's go fly!"
Happens all the time!

I thought there was something more concrete in the rules that required more due diligence, but I don't know where (or if) there is.
Is this what you were thinking of? Not regulatory, but good insight into how it is supposed to work.

625.10 Unserviceable Equipment - Aircraft without a Minimum Equipment List

Information Note:

The following provisions, although considered advisory in nature, have been included in the main body of these standards due to their importance. They are not standards.

(i) CAR 605 requires that all equipment listed in the applicable airworthiness standard, and all equipment required for the particular flight or type of operation, must be functioning correctly prior to flight. The requirement for a particular system or component to be operative can be determined by reference to the type certificate data sheet, operating regulations or the applicable equipment list in the aircraft operating manual.

(ii) Although the responsibility for deciding whether an aircraft may be operated with outstanding defects rests with the pilot in command, an error in this determination could result in a contravention under these regulations. It is for this reason that the regulations require that full details of all defects be entered in the journey log. The pilot in command must be fully aware of the condition of the aircraft if he is to make the correct decision regarding the intended flight. The manner in which the pilot makes this decision, however, will vary according to the type of operation of the aircraft. In the following paragraphs, private and commercial aircraft are considered separately.

(iii) Defects (e.g. buckling, cracks, extensive corrosion) of the skin or structure of the aircraft or of the pressure hull of a pressurized aircraft beyond the safe limits established by the manufacturer in his maintenance manual or other approved maintenance instructions will render that aircraft unfit for safe operation.

(iv) In the case of an aeroplane or helicopter not operated pursuant to Part IV, or an aircraft not operated pursuant to Part VII, the pilot must review the log prior to flight and decide whether any of the defects recorded affect the airworthiness of the aircraft. Reference may be made to the type certificate data sheet, the aircraft operating manual, or any list provided by the aircraft manufacturer respecting equipment that must be operational for the intended flight. The Minister may also approve a minimum equipment list for use by an owner. Any or all of these may indicate that particular items of equipment are mandatory.

(v) In the case of an aircraft operated pursuant to CAR 604, specific instructions must be provided in the operations manual to facilitate this assessment.

(vi) Where in doubt, the pilot should obtain the advice of an AME. This is best done by requesting the AME to inspect the defective system or component to determine its effect upon the aircraft's fitness for flight. By following this procedure and obtaining the AME's signature in the log book in the form of a maintenance release, the pilot will be able to demonstrate, if necessary, that he has taken all reasonable steps to ensure the airworthiness of the aircraft. Inspection of defective systems by an AME, although advisable, is not a legal requirment. As stated earlier, it is the pilot's responsibility to determine whether the aircraft is fit for the intended flight.

(vii) In the case of an aeroplane or helicopter operated pursuant to Part IV, or an aircraft operated pursuant to Part VII, it is not always practicable for the pilot to personally undertake all actions required to determine the airworthiness status, because of the high levels of utilization, complexity of the aircraft, and the limited time available for all the various aspects of pre-flight preparation required. A common standard must be applied to all aircraft of a fleet. For these reasons, the flight training unit and the air operator regulations require the establishment of a formal system for the control of defects.

(viii) Such systems provide a greater degree of confidence that the airworthiness effects of defects have been taken into account, and ensure consistency of application of the standards. They also set limits on the periods for which the repair of a defect may be deferred. For aircraft operated in commercial air service, this system is normally based on the use of Minimum Equipment Lists (MEL), thereby providing the pilot with a sound basis on which to make his decision regarding the intended flight.

(ix) The final decision, however, still rests with the pilot. A pilot who accepts an aircraft with defects, the repair of which has been deferred in accordance with an approved system, has a good defence against any possible charge of flying an unairworthy aircraft, whereas a pilot who undertakes a flight with an aircraft that is not in compliance with the approved system to control the deferral of repairs to defects commits an offence.

(x) The complexity of a system used to control the deferral of repairs to defects will vary according to the type of aircraft operated and the size and nature of the operation and may include reference to an approved minimum equipment list and/or configuration deviation list. In all cases the control system must be described in the air operator's maintenance control manual. Once approved, compliance with those procedures is mandatory.
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ahramin
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Re: Homebuilt airworthiness standards

Post by ahramin »

AirFrame wrote: Wed Jan 30, 2019 7:39 am
ahramin wrote: Tue Jan 29, 2019 2:45 pmIn your example if the dent is affecting the wing's ability to carry a load then I don't see how a pilot could justify saying that airworthiness isn't affected without an engineering analysis. On the other hand if a dent doesn't affect the structure and will not appreciably reduce the performance, it's quite possible that it's airworthy and that a builder would have the knowledge to determine that.
This is the situation I was wondering about. Keep in mind that a good percentage of Amateur-Built Aircraft in Canada are not owned by builders. A builder, yes, could probably make an educated guess how bad the damage is. A non-builder could walk out to the wingtip, give it a shake, and say "it seems solid, and because i'm allowed to say so, I deem it safe! Let's go fly!" I thought there was something more concrete in the rules that required more due diligence, but I don't know where (or if) there is.
Actually I mentioned a more concrete rule than that. The damage needs to be documented. Hopefully that step will help motivate the non-builder to do due diligence on their decision. If they aren't going to bother following the rules, then I don't think more rules will help. Most homebuilt owners I have met - builder or not - already don't document their problems and repairs other than annuals and oil changes. I think encouraging pilots and owners to follow the documentation rules would go a long way towards motivating them to follow the rest of the rules. Unfortunately Transport Canada does the complete opposite and makes it very expensive to follow the rules in the first 25 hours, and by the time the disincentive is gone most homebuilders are already well trained in the habit of not writing anything in the book.
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AirFrame
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Re: Homebuilt airworthiness standards

Post by AirFrame »

torquey401 wrote: Wed Jan 30, 2019 11:23 amIs this what you were thinking of? Not regulatory, but good insight into how it is supposed to work.

625.10 Unserviceable Equipment - Aircraft without a Minimum Equipment List
Yes, I think that is the clause I was thinking of... Despite not being regulatory, as the items are an "information note."
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aeroncasuperchief
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Re: Homebuilt airworthiness standards

Post by aeroncasuperchief »

Transport Canada does the complete opposite and makes it very expensive to follow the rules in the first 25 hours
The A/C is supposed to have 25 snag free hours! A new homebuilt lol
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PilotDAR
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Re: Homebuilt airworthiness standards

Post by PilotDAR »

On the subject of wing damage, though drifting into certified aircraft for a moment, one may find a definition for "negligible damage", Cessna is pretty good at this, and happily tolerant. Piper PA-28's are much less so. You'll have difficulty finding a Piper definition for negligible damage for a PA-28 series plane. In theory, any damage to a Piper PA-28 wing renders the wing unairworthy, and surprisingly difficult to repair. During my research of this problem eight years ago, we did find Piper Service Letter 1095, which allows for disposition of hail damage on a few certain Piper models. The rationale for the choice in models causes me only speculation. Thus two similar performance and airfoil type aircraft have very different tolerances for damage - according to their respective manufacturers. For the PA-28-161 with hail damage, I eventually did issue an approval in concert with the Piper Service Letter (not applicable to that model), though I was required to fly a flight test to demonstrate that the flying qualities were not affected. Similarly, I've had to flight test Cessnas for wing repairs and wing patches, again to assure that flying qualities were not affected.

Taken to extreme, I believe that a certain model Lear Jet requires a factory flight test if a leading edge is replaced.

As for the homebuilt, if the wing is damaged, airworthiness is now in question, as it does not conform to it's original design/configuration. It might be safe for flight, but the process to assert that is not necessarily a flight! In theory, a flight permit should be requested to perform a flight test to validate the condition and effect of a change. I have flown such tests under flight permit authority for both certified and special C of A aircraft, each time with negotiation and resulting conditions from TC. The designer, perhaps the builder, and maybe a very qualified non designer/builder might put forth enough information to a TC inspector to authorize a change to the aircraft. Flying with rectified damage could call into question "safe for flight", and thus affect the validity of the flight authority.
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