Flight 3: N997CZ — Two Hours West of the Field, Flaps for the First Time

After the abbreviated 28-minute Flight 2 and a bit of detective work on the oil temperature wiring, Flight 3 felt like a different airplane — or at least a different experience. Early morning, calm winds, the west side of the field, and a solid two-hour session in the air. It went well enough that I’ve been smiling about it all day. I want to share the data and some of the moments that stood out, and I’m genuinely curious to hear from anyone who’s been down this road with an RV-10 or a similar build.

Getting the West Side — Again

For Flight 2, Manassas Approach had me confined to the east side of the field at only 1,400 feet MSL, which made for a cramped pattern and more stress than I wanted on a second experimental flight. This time, I coordinated early and came out just after 6:30 AM, and the controllers were fantastic. They gave me the west side at 1,800 feet MSL and — when traffic allowed — let me run the full length of the north-south pattern. When arrivals or departures needed the airspace, they’d keep me north of the railroad tracks or south of them as needed. It was a smooth, professional collaboration and made the whole flight feel much more manageable.

Flight track map showing repeated north-south legs west of KHEF at 1800 ft MSL
The flight track over ~2 hours: repeated north-south legs west of KHEF at 1,800 ft MSL. The altitude profile at the bottom shows how stable the session was — no drama this time.

All told, we flew 20.5 gallons out of the left tank, then switched to the right and burned another ~20.5 gallons there — roughly 41 gallons total confirmed by both the fuel totalizer and the fuel truck after landing. The fuel float gauges are a different story (more on that below), but the totalizer was spot-on.

CHTs: Trending in the Right Direction

The cylinder head temperatures were the thing I was most anxious about going in. Flight 1 had a spike past 450°F; Flight 2 saw all six cylinders over the red line briefly. So I was watching the CHT traces like a hawk on departure.

Good news: after the initial climb, everything settled down, and the cruise numbers were genuinely encouraging. Cylinders 3 and 4 spent most of the flight below 350°F — which felt almost cool by comparison to the first two flights. Cylinders 1, 2, 5, and 6 held in the 380–390°F range at 89–93% power. The peak for the entire flight just barely touched 435°F, and only briefly at the start of the climb.

CHT graph for Flight 3 showing all six cylinders well below the red line in cruise
CHT traces for all six cylinders. After that brief spike at climb, everything settled into what looks like a healthy pattern — the yellow caution zone for most of cruise, and cylinders 3 and 4 in the green. Each flight seems to be getting a little cooler.

For those who’ve flown IO-540s through break-in — does this trajectory look about right to you? I’ve been running full rich at near-full power. Would love to hear if anyone has observations on what to expect from here.

Oil Temperature: Night and Day vs. Flight 2

This one made me happy. You’ll recall that the erratic oil temperature readings in Flight 2 were ultimately traced to a poorly crimped wire connection at the oil temperature probe — one that could literally be pulled free by hand once we unwrapped the wire bundle. We re-did the crimp, and the proof is right here in the data.

Oil temperature trace showing a clean, stable climb to 200-209 degrees F with no erratic spikes
Oil temperature for Flight 3. A clean ramp up from cold start to about 200–209°F, then rock-solid for two hours in the green band. No erratic jumps, no disappearing readings. Exactly what it should look like.

Oil temp settled in around 200–209°F for the duration of the flight and never wandered. Oil pressure ran 75–89 PSI throughout. After two flights with that anxious eye on the gauge, seeing a clean flat line in the green was genuinely satisfying.

One thing to note: At the end of Flight 4 (same day, evening flight), oil temp crept up to 215–220°F after a high-power takeoff and immediate landing. We also discovered the oil cooler airflow door wasn’t sitting at a full 90° open position — it had been slightly restricting flow during all previous flights. We’ve corrected that and will watch the temps closely next time. More on Flight 4 in a future post.

RPM and Power

The RPM and power traces look about as clean as you could ask for. We held 2,600–2,690 RPM through most of cruise, operating in the 85–93% power range. There’s a noticeable step-down in the middle of the flight where I reduced power for a bit — I was experimenting with different power settings to see how the CHTs responded — before coming back up to near-full power for the remainder of the cruise portion.

RPM graph showing steady 2600-2690 RPM in cruise
RPM trace for the full flight. A solid cruise band at 2,600–2,690 RPM with one deliberate power reduction mid-flight to observe CHT behavior.
Engine power percentage graph showing sustained 85-93% power
Engine power percentage. Mostly 85–93% throughout cruise — full rich, full power, working those rings in.

The Highlight: First Flap Deployment

This was the part I’d been looking forward to. With two hours of relatively calm airspace and a stable aircraft, Flight 3 was the first time I had enough room to slow down and actually try the flaps — something I hadn’t been comfortable attempting in the tighter, lower patterns of the first two flights.

I stepped through the detents methodically: reflex to the first position (about 3° down from reflex), then to the 15° intermediate, then all the way to full flaps. Each step brought a noticeable pitch change and a mild need for roll trim, but the airplane handled it gracefully. The RV-10 felt remarkably steady through all the configurations — more planted than I expected, honestly.

The first full-flap landing came at the end of Flight 3. We were cleared in from 1,800 feet on a tight, close-in approach — I was running 85 knots, the descent angle was steep, and the CG was fairly far forward (with a couple of cinder blocks in the back seats to nudge it rearward, but still nose-heavy). As I’ve read about in the RV-10 community, the elevator authority at that configuration was noticeable — stick all the way back into my lap for the flare. The landing was fine, but it was an education. On Flight 4 that evening I used a shallower approach with a bit more power on, and that felt considerably better.

Fuel Floats: A Minor Mystery

Both fuel float gauges have been reading high throughout these flights — stuck at 25 gallons on the left and 24 gallons on the right even when the tanks actually hold 30 gallons each. My working theory is that the float arm is bent just slightly too close to one of the fuel tank ribs, causing it to hang up. A quick thump on the tank after landing from Flight 3 dropped the left gauge from its pegged “full” reading down to 11 gallons — right where it should have been given the fuel burned.

Has anyone tackled a stuck float in an RV-10 tank? I’d rather not pull a tank if there’s a less invasive approach. Any tricks for getting better clearance on the float arm without a full disassembly? Would love to hear how others have dealt with this.

Quick Summary of Flight 3

Overall, Flight 3 felt like a turning point. The crimp fix eliminated the oil temperature anxiety, the CHTs are trending cooler with each flight, we got the preferred practice area on the west side of the field, and I finally got to try the flaps. The airplane is performing well and the data is looking progressively more like what I hoped to see. There’s still plenty to sort out — the stuck fuel floats, the AHRS that tumbles on every takeoff roll, and the alternator issue that cut Flight 4 short — but the trajectory feels right.

Thanks as always to the Manassas tower team for being so accommodating. Flying experimental in Class Delta isn’t always easy to coordinate, and they’ve been genuinely helpful.

Your turn: If you’ve built or flown an RV-10 (or any IO-540-powered aircraft through early flight test), I’d genuinely love to hear your perspective in the comments. Whether it’s about CHT break-in, flap behavior, float arm fixes, or anything else that caught your eye in the data — all input welcome. Next up: a post on Flight 4 from that same evening — a shorter flight that ended with a loose alternator belt and more lessons learned.

Please join the discussion or send feedback here: VAF Thread — RV10 N997CZ Takes to the Skies

First Flight: N997CZ Takes to the Skies Over Manassas

Watch: First Flight Video

Watch the full first flight video on YouTube →

The Morning Of

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 showing CHT hot zones
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:

CylinderPeak CHT
CHT 1454°F
CHT 2448°F
CHT 3435°F
CHT 4407°F
CHT 5450°F
CHT 6442°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 CHT temperatures during the first flight
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 graph showing stable readings throughout the flight
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 graph showing stable readings throughout the flight
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.

Cockpit photo showing AHRS-1 tumbled on PFD1 while PFD2 remains 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.

Blue skies.

Up next: Flight 2: N997CZ — Erratic Gauges, an Early Landing, and a Lesson in Crimp Connections →

Please join the discussion or send feedback here: VAF Thread — RV10 N997CZ Takes to the Skies

Images: CHT data and flight track courtesy of engine monitor / EFB export, April 11, 2026, KHEF.

Flight 2: N997CZ — Erratic Gauges, an Early Landing, and a Lesson in Crimp Connections

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.

Oil temperature gauge showing three erratic spikes and a dropout during Flight 2
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.

Up next: Flight 3: N997CZ — Two Hours West of the Field, Flaps for the First Time →

Please join the discussion or send feedback here: VAF Thread — RV10 N997CZ Takes to the Skies

2021 Annual Condition Inspection

Hobbs: 824.1, Tach: 735.4

Annual Condition Inspection started 2/27/21.

Compression check: 79/78/7878

Removed all wheel pants. Need to replace the right wheel. Left wheel and nose wheel were tires and tubes were replaced last year.

Lubricated aileron hinges, aileron external pushrod rod end bearing, flap lower (external) linkages. Lubricated prop, mixture, throttle, cabin heat, and alternate air push/pull controls both inside the cabin and outside in the engine compartment.

Removed spinner. Greased prop with 6 pumps of grease each side. Inspected bolts and safety wire. Reinstalled spinner.

Removed all baggage items from aircraft. Vacuumed carpet, removed interior carpet. Determined both magnetos had been previously IRAN’ed at 398.7 (left) and 525 (right) Tach times respectively. Current tach 735.4.

Removed 8 spark plugs.

Inspected and took pictures internal to each cylinder of intake and exhaust valves. Replaced all spark plugs with new.

Left wheel pant maintainence

Hobbs: 412.9

Did some maintenance today. Had a sneaking suspicion about the left brake rubbing. Opened left wheel pant since it was just a tiny bit wobbly. Found brake caliper and wheel pant mounting bracket all 3 bolts loose allowing up down motion of whole brake assembly. Removed wheel and tightened bolts. Reinstalled. Noticed this very tiny motion two months ago and we should have checked sooner. Lesson learned: if anything changes even a little bit investigate. Left tire at 22 psi. Right tire at 15 psi!! Filled to 35 each. Since the pressure was low the bulging wheel managed to rub and take another small chunk of the fiberglass wheel pant off on both sides. Trimmed and cleaned a bit more using the sanding wheel in a die grinder on both left and right main wheel pants. Reinstalled both wheel pants. Will test fly it tomorrow AM during instrument lesson. Should probably check nose tire pressure but I didn’t have time before leaving today.