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Certification is the single most expensive part of an aircraft. The more "off-nominal" an aircraft is, the harder, and thus more expensive, it is to certify. C
by gvb 7y ago
Certification is the single most expensive part of an aircraft.
The more "off-nominal" an aircraft is, the harder, and thus more expensive, it is to certify. Commercial aircraft (which a "flying taxi" would be) are also much more expensive to certify than general aviation aircraft.
Drone-style "air taxi" aircraft are very different from a systems, reliability, and redundancy point of view than fixed wing (can glide) or rotary wing (can autorotate) aircraft. The FAA is comfortable with those types of aircraft. Convincing the FAA that single and multiple failures (e.g. battery failure) won't cause a drone-style aircraft to fall out of the sky is going to be very expensive.
As an example, it took many years and multiple attempts to get the FAA to certify composite aircraft. Ref:
* Lear Fan https://en.wikipedia.org/wiki/LearAvia_Lear_Fan https://en.wikipedia.org/wiki/LearAvia_Lear_Fan
* Beech Starship https://en.wikipedia.org/wiki/Beechcraft_Starship https://en.wikipedia.org/wiki/Beechcraft_Starship
* Cirus VK30 / ST50 https://en.wikipedia.org/wiki/Cirrus_VK-30#Variants https://en.wikipedia.org/wiki/Cirrus_VK-30#Variants
* Piaggio P.180 Avanti https://en.wikipedia.org/wiki/Piaggio_P.180_Avanti https://en.wikipedia.org/wiki/Piaggio_P.180_Avanti
I don't believe there were any commercially successful aircraft that were primarily composite before the Boeing 787.
- ben_w 7y agoI hadn’t even thought of certification costs, so thank you. How well/badly would that scale with the number of aircraft with the same design? I assume “certify design X for $X” is a separate cost to “certify aircraft Y of model X for $Y”?
- gvb 7y agoAircraft manufacturers get a "type certificate" for a given type of aircraft which applies to all of the aircraft of that model that are made. The type certificate is expensive but gets amortized over all the aircraft produced. Changes (depending on how significant they are) can be covered by a "supplemental type certification" which leverages the underlying type certificate and only has to show that the changes are OK. Supplemental type certificates are much less expensive and is used to certify different models of a given aircraft (e.g. the 737-800 Max is a STC on a STC on a STC ... all the way back to the original 737 Type Cert[1]). There are also ongoing maintenance monitoring and updates that go into maintaining an aircraft's "airworthiness certificate". The manufacturer must monitor the fleet of aircraft it produces and produce maintenance instructions over the lifetime of the aircraft, including addressing unexpected fatigue and wear issues. Ref: https://en.wikipedia.org/wiki/Type_certificate https://en.wikipedia.org/wiki/Type_certificate [1] https://en.wikipedia.org/wiki/Ship_of_Theseus https://en.wikipedia.org/wiki/Ship_of_Theseus
- nradov 7y agoFor certification purposes the FAA categorizes drone-style aircraft as "powered lift". https://www.faa.gov/aircraft/air_cert/design_approvals/rotorcraft/ https://www.faa.gov/aircraft/air_cert/design_approvals/rotor...
- gvb 7y agoThanks, that's very helpful. Looking at Wikipedia's entry https://en.wikipedia.org/wiki/Powered_lift https://en.wikipedia.org/wiki/Powered_lift I don't see any commercially successful aircraft. There are some military aircraft[1], experimental aircraft, and a some unsuccessful commercial aircraft. None is "drone style" yet. Being the first to type certify a new style of aircraft is very difficult and expensive, which was my point with the list of composite aircraft. Composite aircraft (in my mind) seems much less of a change than powered lift. Maybe ballistic recovery systems[2] will make powered lift certifiable with a reasonable level of effort. The nice thing about BRS is that it is already flight proven and accepted as an emergency recovery system. [1] The military is willing to take more risks - helps that the jets have ejection seats. The Osprey had 12 hull-loss accidents with a total of 42 fatalities (no ejection seats and it cannot autorotate). Ref: https://en.wikipedia.org/wiki/Bell_Boeing_V-22_Osprey#Accidents https://en.wikipedia.org/wiki/Bell_Boeing_V-22_Osprey#Accide... [2] https://en.wikipedia.org/wiki/Ballistic_Recovery_Systems https://en.wikipedia.org/wiki/Ballistic_Recovery_Systems