Davin News Server

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.

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.

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:

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).

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.

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.

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

=====

August:

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+ Popular Climate Study Exposed As Propaganda

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