Davin News Server

On 2025-08-17 18:48, AlleyCat wrote:
> 
> On Sat, 16 Aug 2025 18:55:11 -0700,  Alan says...
> 
>>> "Range" - phrase not found
>>> 
>>> "Distance" - phrase not found.
>>> 
>>> "Miles" - phrase not found.
> 
>> You were claiming "FAA rules" would limit Joby to "<100 mile round
>> trips".
> 
> Jes.
> 
> Based on the FAA's regulations for commercial powered-lift (eVTOL)
> aircraft, and the hypothetical figures you provided, the maximum 
> allowable trip distances would be significantly less than the
> aircraft's total capacity.

Which is 154.6 miles as of right now.

> 
> The FAA's safety rules require an aircraft to have enough power to
> fly to the destination, then to an alternate, and then have a 
> minimum 20-minute reserve.

No, that is incorrect.

But you go ahead and try to quote the regulation.

> 
> Using your example of an aircraft with a 150-mile total capacity
> (100-mile range + 50-mile reserve), and assuming a cruising speed of
> 100 mph, here are the maximum trip distances the FAA would permit:

Wrong cruising speed.

> 
> One-Way Trip with a Charging Station at the Destination
> 
> The maximum one-way trip would be approximately 58 miles. This
> allows for:
> 
> 58 miles to the destination.
> 
> 58 miles to an alternate airport (assuming the alternate is the same
> distance away).

Which is a valid assumption... ..why?

> 
> 33 miles for the 20-minute FAA-mandated reserve.
> 
> Total = 149 miles (within the 150-mile total capacity)
> 
> Round Trip with No Charging Station at the Destination
> 
> The maximum round-trip distance would be approximately 20 miles (10
> miles each way). This allows for:
> 
> 10 miles to the destination.
> 
> 10 miles back to the departure point.
> 
> 10 miles to an alternate airport.

Again, assuming that the alternate will automatically just be the same 
distance away from the destination and departure airports is just...

...really dim.

> 
> 33 miles for the 20-minute FAA-mandated reserve.
> 
> Total = 63 miles (well within the 150-mile total capacity).
> 
> The FAA would not allow a flight to be planned to the full 100-mile
> range, because it would not leave enough power for the required 
> alternate and safety reserves.
> 
>> And neither the original FAA rules for conventional aircraft nor
>> the revised rules define things in terms of range, distance or
>> miles.
> 
> LOL.
> 
> OK.
> 
>> Which is why you've pivoted.
> 
> Nope.
> 
> Based on FAA regulations, the flight distance for an electric VTOL
> aircraft with a 100-mile range and a 50-mile reserve would be 
> limited to a 50-mile trip, as a 20-minute energy reserve is required
> for powered-lift aircraft capable of continuous vertical landing
> along the route. If the aircraft cannot guarantee a vertical landing
> capability throughout the flight, it must adhere to fixed-wing
> aircraft requirements, which necessitate a 30-minute daytime and 45-
> minute night-time reserve.
> 
> Here's a breakdown of the key considerations:
> 
> Energy Reserves: The FAA had initially considered applying fixed-
> wing aircraft energy reserve requirements to powered-lift aircraft 
> (30 minutes for day flights, 45 minutes for night flights). However,
> in response to industry concerns, the FAA has allowed for a 20-
> minute energy reserve for powered-lift aircraft, aligning with
> existing helicopter regulations. This exemption is conditional on 
> the aircraft being "continuously capable of conducting a landing in
> the vertical-lift mode along the entire route of flight". If this
> cannot be assured, the fixed-wing energy reserve requirements apply. 
> Part 23 Regulations: While the FAA initially considered certifying
> eVTOLs under Part 23 (for aircraft under 12,500 pounds), it later
> decided to certify them under Part 21.17(b) as special class
> aircraft. Part 23 is still relevant as the FAA draws upon aspects of
> these regulations, along with others (parts 25,27,29,31,33, and 35)
> to establish airworthiness standards for powered- lift aircraft.
> 
> Operational Limitations:
> 
> Early estimations for eVTOL range suggested an initial limitation of
> 50 miles. However, with advancements in battery technology, ranges
> are increasing, with some aircraft already achieving 155 miles and
> others targeting 100-mile ranges for urban routes. It is important
> to note that the actual flight distance will depend on various
> factors like weather conditions, payload, and the specific 
> performance characteristics of the aircraft.

Note that (assuming you copied and pasted this) the source is using 
range to mean the maximum range of the craft and that is seen by the 
fact that they contrast the "early estimations" of 50 mile with the 155 
miles that we already know the Joby prototype is capable of

> 
> Special Airworthiness Certificates: Mayman Aerospace has secured
> Special Airworthiness Certificates (Experimental Class) for its VTOL
> aircraft, indicating that the certification pathway is being
> actively developed. These certificates are crucial for testing and
> developing these innovative aircraft, paving the way for future
> commercial operations.
> 
> In summary, while the aircraft has a 100-mile range and a 50-mile
> reserve, the current FAA regulations concerning energy reserves for
> powered-lift aircraft would effectively limit the operational range
> to 50 miles, provided the aircraft maintains vertical landing
> capability throughout the flight. As the eVTOL industry develops and
> new regulations are established, these operational limitations may
> evolve.
> 
> https://www.faa.gov/sites/faa.gov/files/2120-
> AL72_Integration_Powered- 
> Lift_Pilot_Certification_and_Operations_Miscellaneous_Amendments_Related_to_Rotorcraft_Airplanes_Final_Rule.pdf
I don't know where you got your text from, but the words "In summary" 
appear only once in the PDF for which you provided a link, and the words 
that follow "In summary" are totally different.

'In summary, the FAA notes that subpart G of part 91 applies to the 
operation of large and transport-category U.S.-registered civil 
aircraft.' [Page 468, BTW]

Similarly, there isn't a single occurrence of the term "Energy 
Reserves:" (with the colon), in the entire PDF.

Nor "Operational Limitations:".

Nor "Mayman Aerospace".

A cursory searching using more of the text you quote as if it's from 
that FAA PDF suggests you relied on an AI summary.

In short, you're attempting to pull a fast one (lie) and hoping that no 
one will notice.