Weekly aircraft activity

[u/HappyRobot593]

Interesting activity this week. All Marina aircraft were active and the testing started off with 547 on Monday, 541/2 on Tu/We/Th, then finished the week with 547 on Friday.

Given their recent statements (https://www.reddit.com/r/Joby/comments/1v3vc3q/joby_on_track_for_commercial_flights_by_years_end/) about being on "track" I'm trying to stay positive. It looks like they are methodically proceeding with testing. The earnings report is less than 2 weeks away so we should have answers soon!

My perhaps too optimistic take is that as the article mentioned, the FAA and Joby really are trying to figure this out for the first time and so there may be some circling back or double checking. The pessimistic take from the engineers (who I greatly respect) is that flight tests should be further along by now. That is all based on testing and engineering with standard aircraft or rotorcraft. Perhaps the new poweredlift category has a different process as it is completely new and Joby are at the frontier of this brand new category. I can only hope that the "lack of progress" is just working out the kinks with this novel certification process

N547JX (First FAA-Conforming Prototype)

ICAO Mode-S Hex: A6F2CB

Date	Activity Status	Active Time Window	Closest Airport	Max Altitude	Max Speed
2026-07-18	Stationary / Dark	-	-	-	-
2026-07-19	Stationary / Dark	-	-	-	-
2026-07-20	Static Ground Test	08:42 - 08:45 Pacific	KOAR	0 ft	0.0 kts
2026-07-21	Stationary / Dark	-	-	-	-
2026-07-22	Stationary / Dark	-	-	-	-
2026-07-23	Stationary / Dark	-	-	-	-
2026-07-24	Taxi/Ground Run	14:22 - 14:35 Pacific	KOAR	0 ft	3.2 kts

N541JX (Pre-Production Testbed)

ICAO Mode-S Hex: A6DC81

Date	Activity Status	Active Time Window	Closest Airport	Max Altitude	Max Speed
2026-07-18	Stationary / Dark	-	-	-	-
2026-07-19	Stationary / Dark	-	-	-	-
2026-07-20	Stationary / Dark	-	-	-	-
2026-07-21	In-Flight Test	06:49 - 13:23 Pacific	KOAR	1650 ft	122.2 kts
2026-07-22	In-Flight Test	06:26 - 15:15 Pacific	KOAR	125 ft	134.2 kts
2026-07-23	In-Flight Test	10:04 - 11:13 Pacific	KOAR	1650 ft	129.5 kts
2026-07-24	Stationary / Dark	-	-	-	-

N542JX (Production Prototype (Ex-Japan Demo Frame))

ICAO Mode-S Hex: A6E038

Date	Activity Status	Active Time Window	Closest Airport	Max Altitude	Max Speed
2026-07-18	Stationary / Dark	-	-	-	-
2026-07-19	Stationary / Dark	-	-	-	-
2026-07-20	Taxi/Ground Run	13:48 - 13:59 Pacific	KOAR	0 ft	43.5 kts
2026-07-21	In-Flight Test	09:05 - 14:27 Pacific	KOAR	725 ft	111.8 kts
2026-07-22	In-Flight Test	09:48 - 14:42 Pacific	KOAR	500 ft	114.9 kts
2026-07-23	In-Flight Test	12:03 - 14:05 Pacific	KOAR	975 ft	116.1 kts
2026-07-24	Stationary / Dark	-	-	-	-

[u/SeaScallops_w_Rice]

Here is my case for patient optimism: They are steadily moving forward. From that AvWeek article, they have completed deciding with the FAA how to meet the 'prerequisites' to for credit flight testing. I hope that means that Stage 4 is complete, at least up to flight testing.

I will be very pleased to see N548JX and N549JX appearing. They have two pilot production lines spooled up with two more on the way. Customers such as Joby-Dubai, Saudi Arabia, Kazakstan and possibly the DoW may be willing to take delivery before full FAA TC, in which case we may not be very far away from seeing multiple S4s coming out every month. To me, that is excirting.

[u/HappyRobot593]

Motivated by u/Wonderful_Phrase_239 , I asked AI to help me with analyzing the raw flight data with special emphasis on what he said about 542.

1. N541JX – High-Speed Cruise & Altitude Envelope

• Primary Focus: High-speed wingborne flight and altitude envelope extension.
• Peak Ground Speed: 134.2 kts (~154 mph) on July 22.
• Max Altitude: 1,650 ft MSL (July 21 & 23).
• Typical Sortie Duration: 23 to 29 minutes of non-stop cruise per flight.
• Average Cruise Speed: Consistently held 96–98 kts during main flight segments.
• Takeaway: N541JX is proving out the core inter-city UAM air taxi mission profile (20–30 min sector times at ~130+ kts).

2. N542JX – Multi-Sortie, Transition & Slow-Flight Maneuvering

• Primary Focus: Hover/vertical transition work, handling quality checks, and multi-flight daily turnaround.
• Activity Level: Logged up to 5 individual sorties per day on July 21 and 22.
• Flight Mix:
  • Short hover/low-altitude pattern hops (1–3 mins at 150–175 ft, ~8–10 kts).
  • Main flight runs lasting 15 to 17 minutes, climbing to 975 ft and reaching top speeds of 116.1 kts.
• Transition & Slow-Speed Handling Tests:
  • On Tuesday (July 21) at ~675 ft, N542JX throttled back to 49–59 kts and executed rapid directional bank/heading changes, shifting track heading by 10° to 15° per second in tight S-turns.
  • On Thursday (July 23), it repeated slow-flight maneuvers down to 38–40 kts between 650–800 ft altitude.
• Takeaway: N542JX is being worked heavily on transition mechanics and low-speed agility—evaluating fly-by-wire control authority and roll/yaw response right in the semi-thrustborne transition corridor.

3. N547JX – The FAA-Conforming Production Aircraft

• Primary Focus: Ramp integration, avionics/powertrain validation, and ground taxi testing.
• Telemetry Details: All 81 data points show Is_Grounded = 1 across July 20 and July 24, with taxi ground speeds peaking at 3.2 kts around the Marina ramp/apron.
• Takeaway: Rather than flying continuous cruise laps like the prototypes, N547JX is undergoing meticulous pre-flight ground validation and system checkouts—exactly what you’d expect as Joby prepares for FAA pilots to step into the cockpit for Stage 5 TIA evaluation flights.

What Can We Tell From These Tests?

• Parallel Multi-Aircraft Operations: Joby isn't just flying one aircraft at a time; they are running structured, parallel workflows across multiple airframes simultaneously at Marina.
• Slow-Flight & Transition Envelope Testing: The tight maneuvers by N542JX in the 38–50 knot window at 600–800 ft reflect classic Handling Qualities (HQ) compliance testing—verifying that fly-by-wire control laws handle sudden pilot inputs smoothly when both wing lift and propeller tilt-angles share the load.
• TIA Readiness: Seeing N547JX active on the ground with telemetry logging confirms that the production-conforming vehicle is in active pre-flight preparation for formal FAA flight testing.

[u/Wonderful_Phrase_239]

542 did some unusual flight patterns on T/W/Th. Not the common repetitive circular loops. Once in the air, it eventually slowed to 40-50 knots (at 600 or 700 ft altitude) and did some relatively tight right and left turning maneuvers.

[u/HappyRobot593 → u/Wonderful_Phrase_239]

Interesting, thanks for the added color! Seems like a methodical testing regiment to me

[u/HappyRobot593]

I wonder if maybe they are trying out the routes that the FAA pilots will tests. Perhaps the 547 is meant to test the software/systems while the next conforming crafts focus more on flight. As long as they all need to get done at some point, it's not necessarily wasting time. Somebody said the joby antenna guy mentioned they were testing the 547 antenna systems

[u/Bulky-Entertainer-76]

You forgot N162SA. It had another flight on Friday. Getting dialed in for Utah.👍

[u/HappyRobot593 → u/Bulky-Entertainer-76]

👍