Flight 2 took place a week after the first flight, on April 17, 2026. If you haven’t read the first flight post, that’s probably the right place to start — it covers the aircraft, the context, and the CHT spike that set the stage for everything that followed.
This one was shorter, more stressful, and ended with a maintenance discovery that turned out to be both the cause of the problem and a straightforward fix. Here’s what happened.
The Setup
The original plan for Flight 2 was the same as Flight 1: west side of the field, 1,800 feet MSL, north-south legs in the practice area. But when I made the coordination call to Manassas tower that morning, the picture changed.
The controller asked me to keep my pattern on the east side of the field. On the east side, they could give me 1,400 feet MSL — 400 feet lower than Flight 1, and on the side of the field with less room to work in. For a second Phase 1 experimental flight, that wasn’t ideal. But it was what was available that day, so that’s what we did.
Full fuel on both sides — 30 gallons left, 30 gallons right.
The Flight
Takeoff was unremarkable except for two things that repeated from Flight 1: the AHRS-1 attitude indicator tumbled on the takeoff roll (same behavior as before — isolated to PFD1, PFD2 and the G5 standby both remained stable), and CHTs spiked above the warning limits during climb. This time all six cylinders went over 435°F, peaking somewhere in the 460–475°F range before settling down. Higher than Flight 1’s peak, which was unwelcome, and attributable to the later time of day and warmer ambient temperatures.
We were at 1,400 feet MSL with a compact pattern on the east side of the field. Not exactly the relaxed cruise conditions you’d want for watching CHTs settle, but the temperatures did come down as we moved out of the climb and into cruise power.
Then the Oil Temperature Started Misbehaving
Flight 1 had shown clean, stable oil temperature throughout. Flight 2 did not.
Partway through the flight, the oil temperature gauge spiked suddenly to an obviously unrealistic reading — well above what oil temperature can physically reach in a few seconds. I knew it wasn’t a real temperature (temperature can’t rise that fast), but an erratic gauge is still an erratic gauge. I noted it and kept flying.
It happened again. Then a third time — and this time the gauge didn’t just spike, it went dark. No reading at all for a minute or two.
The oil temperature trace from Flight 2. Three erratic spikes to off-scale high readings, followed by the gauge going completely dark. Oil pressure remained stable throughout — the problem was instrumentation, not the oil system itself.
Oil pressure was steady the entire time — 75–80 psi, never wavering. That was reassuring. A failed oil system shows up in the pressure first; the pressure was fine. But flying with no oil temperature indication, in a tight pattern at 1,400 feet, on a second experimental flight, with CHTs that had already been high — that was enough. I made the call to land early and figure it out on the ground.
Total flight time: approximately 28 minutes. Fuel burned: 9.5 gallons from the left tank (confirmed by both the totalizer and the fuel truck, which put exactly 9.5 gallons back in).
The Diagnosis
Post-flight, we went looking for the cause. It didn’t take long.
In the firewall-forward wiring, near the oil temperature probe, we found a crimp connector that hadn’t grabbed the wire properly. When we unwrapped the bundle and pulled on the wire, it came free by hand — zero resistance. That was the culprit: an intermittent connection that would open under vibration, spike the reading to an implausible value, then reconnect. The third time it disconnected, it stayed disconnected long enough to drop the gauge entirely.
I’d actually noticed some finickiness with these wires before the first flight — wiggling the bundle in the hangar had produced erratic gauge readings on the ground. I wasn’t able to reproduce it consistently enough to isolate the cause before Flight 1, and it didn’t manifest during Flight 1. It clearly manifested during Flight 2.
The fix: re-do the crimp, properly this time. Wrap the bundle back up. Done.
Flight 3 would show whether the fix held.
What I Took Away
Flight 2 was short and more stressful than I’d planned. But the outcome was fine—nothing broke, I made a conservative decision to land when my instrumentation became unreliable, and we found and fixed the actual problem before the next flight. That’s the process working as it should.
A few things I’m carrying forward:
Known issues need abort criteria before departure. If something is behaving oddly on the ground, decide in advance what you’ll do if it shows up in the air. Don’t leave that decision for the moment.
Airspace coordination is worth doing ahead of time—and worth holding firm on. Getting assigned the east side at 1,400 feet added unnecessary pressure to an already-demanding flight. For subsequent flights, I’ve made a point to coordinate specifically for the west side of the field. Until I have full confidence in the aircraft and it’s ready to venture further outside the Class Delta for the remaining flight test program, having the more open, higher-altitude practice area on the west side is genuinely important—not just a preference. I’d encourage any experimental builder doing early Phase 1 testing at a busy Class D airport to have that conversation with the tower in advance, and be clear about what you need and why.
The fuel totalizer appears accurate. Having the refueled quantity match the totalizer reading exactly was a genuinely useful data point—I’m more confident in that system now.
As always, if you’ve been through something similar—erratic instrumentation on an early test flight, a wiring issue that surfaced at an inconvenient time, or a tricky judgment call about when to land—I’d really like to hear about it in the comments. I don’t have all the answers on this airplane yet, and the conversations here have been more useful than I expected.
We had hoped to be wheels-up by 6:30 AM. First flights have a way of humbling your schedule.
The day actually started on time — at around 6:30 AM we were already on the radio with the Manassas tower, working through the coordination that my operating limitations required before I could fly. That conversation shaped the flight plan for the morning. I asked the controller for 1,800 feet MSL inside the Class Delta, offset between one and two miles west of the runway, with north and southbound legs west of the field. It was a compromise altitude — lower than I would have liked for gliding distance safely, but it was as high as we could go inside the Delta without conflicting with Washington Dulles airspace to the north. The tower was accommodating and we had our area sorted.
What we didn’t have sorted quite yet was the aircraft. By the time we’d finished the walkaround, coordinated with the local fire department (who graciously agreed to stand by on-field — something I’d strongly recommend to any first-time experimental flyer), and began taxiing out, it was closer to 8:30. Two hours of pre-dawn nerves, checklists, and quiet conversations on the ramp.
The fire crew’s presence wasn’t just a safety net — it was a reminder of how seriously we were taking this. This wasn’t a routine departure. This was the culmination of years of building, hundreds of hours in the hangar, and a lot of faith in the process.
What Came Before: Engine Time at First Flight
One thing worth noting for anyone following along with their own build: we kept pre-flight engine running to an absolute minimum.
By the time we lined up on RWY34R that morning, the engine had seen just two cold starts and one brief taxi test to break in the brakes — probably less than 10 minutes of total run time prior to the day of the first flight. The conventional wisdom on Lycoming break-in is to get the engine to altitude quickly, run it hard, and let the rings seat properly. So we kept ground time short and intentional. I believe this is also to prevent “gazing” the cylinder walls — a condition that can occur from prolonged low-power operations before the engine is thoroughly broken in, and which can make proper ring seating much harder to achieve afterward.
That philosophy was tested on the morning itself. The long taxi out gave the engine time to heat up, and by the time we completed our run-up, CHTs had climbed to around 405°F — already nudging our yellow warning limit. I made the call to pull back to idle for a couple of minutes and let things cool down before attempting the takeoff roll. It was the right call: temperatures settled, we confirmed everything was in order, and we lined up.
We knew engine temperatures were going to be a story on this flight. We just didn’t fully anticipate how much of a story.
The Flight Area
Per my operating limitations and the coordination with Manassas tower, the first flight was conducted inside the Class Delta airspace, one to two miles west of the runway at 1,800 feet MSL, with north and southbound racetrack legs west of the field.
The altitude was a deliberate trade-off. Higher would have been better for cooling airflow and giving me more options in an emergency, but 1,800 feet was the ceiling we could use without stepping into Dulles’s airspace. You work with what you have.
Flight track over Manassas (KHEF). Red segment marks where CHTs exceeded 435°F — concentrated at the departure end of RWY34R.
Takeoff and Climb: The CHTs Tell the Tale
Liftoff from RWY34R was clean. The RV-10 accelerated exactly as I was expecting — consistent with the seven hours of transition training I’d done with Mike Seeger in Vernonia, Oregon before the build was complete. That experience paid off; there were no surprises on the runway and the controls felt immediate and responsive — more on the flight characteristics in a future post. For now, let’s talk about what the engine monitor was screaming at us.
We had configured our warning limits conservatively for the first flight:
Yellow (caution): 400°F CHT
Red (warning): 425°F CHT
Remember, CHTs were already at around 405°F during run-up, before we even started the takeoff roll. The climb loaded the engine further and temperatures rose quickly.
At 13:01:19 UTC — roughly a minute after liftoff — cylinder head temperatures peaked across the board:
Cylinder
Peak CHT
CHT 1
454°F
CHT 2
448°F
CHT 3
435°F
CHT 4
407°F
CHT 5
450°F
CHT 6
442°F
Five of six cylinders exceeded our red warning limit. CHT1 hit 454°F — well into territory that gets your attention. The aircraft’s engine monitor was painting a very pink picture.
All six CHTs during the first flight. Peak at 13:01:19 UTC with CHT1 reaching 454°F. Temperatures were above 435°F for approximately 2 minutes before trending down.
The good news: we had expected elevated temperatures during break-in, had briefed the scenario, and had a plan. We maintained climb power, kept the nose slightly lower than we might otherwise to maximise airflow, and watched the numbers. Within about two minutes, CHTs began their descent back toward normal operating range and continued to trend down through the rest of the flight as the engine settled in.
Not everything was alarming, though. Oil temperature and oil pressure both told a completely different story — and a reassuring one.
Oil temperature started around 65°F at engine start, climbed steadily through the long taxi, reached roughly 185–190°F by the time we lifted off, peaked at around 195°F shortly after takeoff, then settled into a rock-solid band of 185–195°F for the entire flight — squarely in the green, never threatening the yellow or red zones. Whatever the CHTs were doing, the oil temperature was happy throughout.
Oil temperature throughout the flight. Climbed steadily during taxi, peaked at ~195°F shortly after takeoff, then held a stable 185–195°F band for the duration — solidly in the green zone throughout.
Oil pressure was equally well-behaved. It jumped to around 70 psi immediately at startup, showed some normal variability during taxi at idle power, then spiked cleanly to ~85 psi as full power was applied for takeoff. From there it held a steady ~80 psi through the entire flight — solidly in the green band — before settling back down during the taxi in after landing. On a brand new engine, seeing oil pressure that stable and consistent is exactly what you want.
Oil pressure throughout the flight. A brief spike to ~85 psi at full-power takeoff, then a steady ~80 psi through the pattern — well within the green band for the entire flight.
The flight track map tells the same story geographically — you can see the red segment (CHT > 435°F) concentrated right over the departure end of the runway, fading as we worked through our planned pattern to the southwest of the airport.
One other thing you’ll notice if you watch the cockpit video: the primary flight display — connected to Attitude and Heading Reference System number one (AHRS-1) — tumbled during the takeoff roll. Importantly, this was isolated to screen one. Primary flight display two, connected to AHRS-2, remained solid throughout, as did the G5 standby attitude indicator. So while the artificial horizon on screen one was misbehaving, we had two other reliable attitude references in the cockpit the entire time. The image below captures it clearly — PFD1 on the left showing a wildly incorrect attitude while PFD2 on the right remained perfectly stable.
PFD1 (left, circled) showing a tumbled attitude during the takeoff roll. PFD2 (right, circled) and the G5 standby both remained solid throughout.
Notably, AHRS-1 corrected itself shortly after takeoff — before we even reached the first turn — so the tumble was brief. That said, “it fixed itself” isn’t a satisfying answer for a system you’re counting on, and it’s not ideal, absolutely something that needs to be resolved before any IFR or night flight. It’s sitting lower on the priority list right now while we focus on the engine temperatures. One squawk at a time.
The Builder’s Conundrum: Run It Hard vs. Take It Easy
Here’s the tension nobody talks about enough.
A brand new Lycoming needs to be run like you stole it. Full power, or as close to it as you can manage, for as long as it takes to get the rings to seat against the cylinder walls. We’re talking an hour or two of hard running — sustained high power, letting the pressure in the combustion chamber do the work of pushing those rings out and wearing them in. The payoff is a marked drop in cylinder head temperatures on subsequent flights as the seal improves and the engine breathes properly. You watch for that drop like a hawk.
But running an engine flat-out is exactly at odds with what you want to do with a brand-new airframe. Every builder’s instinct — and the right instinct — is to build up slowly. Fly a little conservatively at first. Take things one step at a time. Get familiar with the aircraft before you start pressing limits.
Those two requirements don’t coexist gracefully.
This isn’t our first rodeo — we previously built and flew an RV-7A (N997RV), and we had elevated cylinder head temperatures on the first several flights of that aircraft too. That experience helps. You know the temperatures are coming, you’ve seen the trend lines before, and you have some confidence that the numbers will fall as the engine breaks in. But it doesn’t make the decision any easier when you’re staring at 454°F on CHT1 and trying to decide how hard to push a machine you’ve spent years building.
What We Learned
A few takeaways that might help others approaching their own first flight:
1. Brief the temperature scenario in advance. We had talked through “what do we do if CHTs spike” before we ever started the engine that morning. That meant when the warnings lit up, there was no panic — just a pre-briefed response.
2. Watch your pre-takeoff temps carefully. The long taxi and run-up had already pushed CHTs to ~405°F before we ever lifted off. That warm baseline mattered. If temperatures had continued to climb during run-up, I would have aborted and tried again later in the day. Knowing your limits — and sticking to them — is the whole game.
3. Keep the new engine ground running time to a minimum — get it flying at high power quickly. The elevated temps during climb are part of that process — uncomfortable to watch, but expected.
4. Coordinate your airspace early. The 6:30 AM tower call was one of the better decisions of the morning. Having the flight area locked in before we even went through the walkaround meant one less variable to manage when we were ready to fly.
5. Set your limits to inform, not alarm. Our conservative warning thresholds (400°F yellow, 425°F red) meant we were informed early. Some builders set limits higher to avoid nuisance alerts; I’d argue starting conservatively and adjusting based on data is the better approach.
6. Have the fire department on standby and mean it. Not as a formality. Talk to them beforehand, make sure they know the aircraft and where you’ll be operating. They were professional, prepared, and I hope we never need them — but knowing they were there made a difference. We also brought them donuts as a bribe, which we highly recommend as part of any first flight preflight checklist.
What’s Next
The RV-10 is now officially a flying machine. Phase 1 flight testing has begun, and there’s a lot of data to collect and share. Future posts will cover:
Flight handling and control harmony
Engine break-in progress and CHT trends over the first 25 hours
Performance numbers vs. the Van’s specs
Lessons learned from the build that showed up on the flight line
If you’re building an RV-10 (or any experimental), I’d love to hear from you. Drop a comment below or reach out directly — the EAA community is one of the best parts of this whole journey.
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