Short trip this morning from Charlotte over to Raleigh. 104nm
I usually take Citabria, land Raleigh East (W17) and get Uber to office.
With Avanti and IFR would be departure and arrival making trip longer and burning more fuel.
Flew 17,500 VFR
104nm burned 330 pounds with power pulled back to 100gph in the short cruise.
TAS 293 knots
8 minutes out power to idle descending around 2500ft/min. 26 minute flight time.

I landed on runway 32, got on the brakes a little and turned off before the end onto Charlie.

Previous Avanti to Raleigh trips I have kept power up burning way more fuel and probably saving me 92 seconds.

Back home this afternoon will be at 16,500.
May pull power back a bit more to enjoy the flight 2 more minutes.

Headed alone (light weight) to Louisiana Sunday. I think I will attempt FL400 if not too hot.

Can you do me a favor, Brad? Slow down to Vr/Vbg speed at altitude and tell me what fuel burn is?

(maybe there's a limitation on the pressurization system on how far back you can pull power, but if not, I'd be really curious)

Adam,
If I had wanted to go slow I would have flown the Citabria


Doubt she will hold pressure anywhere close to VR….might be wrong.
Will try 150 KIAS once I get to cruise then reduce more If I can.

Pretty day for VFR back to Charlotte at 16,500

This morning at 17,500 feet and 670lbs per hour I saw .43nm per pound.
23 knot tailwind component.

Jeff,

Speed varies of course but I generally see computed Vref of 117. Sometimes it's a bit higher but I'm generally pretty light.

Thanks Anthony!!

That’s interestingly information!! I believe it!!

I’m glad it wasn’t me, I would have definitely had to go around and diverted.

This morning at 17,500
ISA+16
weight ~9300
293 TAS on 670 lbs/hr so .437nm/lb of fuel

This afternoon at 16,500
ISA +18
weight at first test ~10,700 (280 gallons CAA price at Atlantic FBO in RDU...woohoo)
149 IAS
197 TAS on 510lb/hr so .386nm/lb
172 knots true...ouch

172 IAS
227 TAS on 550lbs/hr so .413nm/lb

next
~214 IAS..did not get IAS in picture
278 TAS on 670lbs/hr so .415nm/lb

A bit surprised 670lbs/hr was as efficient as 550lbs/hr at this altitude.

Burned 410 lbs on return trip vs 330 on way over.
About the same ~20-25 knot wind both ways
Pressurization held just fine even descending 3200fpm with power at 1.5 TORQ each side.

Thanks Brad! Wow, did not expect that either. And especially not that 149KIAS would be the last efficient!

I have played around a lot with efficient power settings, my thoughts are as follows:

Anything below 180 IAS and the plane drags. Perhaps it glides well at those speeds (it's above best glide) but it drags under power and you are more efficient on a nm/lb basis by speeding up. I have heard Italian Air Force guys say same thing.

That said, if you are trying to loiter, say you have a gear issue and need to pump it down while burning the least fuel you can, 5k feet or less, it's tough to get fuel burn much below 600lbs/hr. If memory serves, I did a hold at 7k feet (in Denver, so figure ~2k AGL) and pulled power back to 600lbs torque. Was flying around at 150IAS clean on about 550lbs/hr total.

When flying VFR below FL180, I usually set for 200IAS for short flights. Seems like a good balance of speed and efficiency. Pushing up to 260IAS only shaves a tiny bit of time and you end up burning more fuel.

Would it not hold true that faster is always better given the cost of airframe hours?
In other jet threads on this forum, reader analysis of the cost per hour for gear, engine, and time inspections appears to suggest airframe savings will always exceed the cost of fuel saved. 10 year items on a Phenom 100 for example, the airframe hour reserve is substantial.

Even if you ignore a cost of the Avanti gear overhaul, you still need to factor in the C and D inspection. That D inspection is a biggy. Simms-air say they have 3600 hr. D inspection going with above average squawks costing 200K and 900 man hours. Add brakes, props, hot sections, etc, it’s reasonable to assume trading fuel for time is not a winning strategy?

Only if you overhaul

Gear on Avanti is not mandatory part 91. Straight from the FAA.

Only if you overhaul

Gear on Avanti is not mandatory part 91. Straight from the FAA.

re: hours - I think that is more applicable for long flights. On the short ones, the percentage of time difference from different speeds is so much lower.

My 3000hr items and C check is now at 400k. The D check I expect to be the same without gear oh. So I echo your point...time is money.

My 3000hr items and C check is now at 400k. The D check I expect to be the same without gear oh. So I echo your point...time is money.

I'm sure to at least some extent it's unique to my plane, but the parts delay is real.

We are close to 12 months being down. Some of that was expected with a Garmin upgrade.
So much of the delay is just lost man hours....they found an issue and it tacks on 2 weeks. Find another issue, 2 more weeks etc. Part says it will come in 2 weeks but takes 3....I feel like starting another business that simply provides accurate ETA/lead times to shops. Its like no one spends time in logistics planning.

Here is my saga:
Paint/Interior was vastly delayed and the shop we used left a lot to be desired. We are finding tons of corrosion (like in the last 4 weeks ) that should have been found and fixed when it was stripped and re-painted. I guess its possible the corrosion is new since last October but if so, I suspect their prep was lacking if we are getting corrosion under new paint after 4 months. We also discovered the paint color they used was not the right part number. As we went to repaint sections that had corrision the color was off. Sure enough, looking back through emails we had it down to 2 shades...the shade we picked (and was recorded in the log book) is not what was applied. They applied the wrong one but put the correct one in the logs. The color itself was no big deal as the shades were so close you only would know when they are next to each other. That added about 3 weeks by the time the current shop scheduled the paint, found the issue, got the correct codes and rescheduled the fix.

We also discovered the toilet was not reinstalled properly and had been leaking...so add a few weeks to get it cleaned, new insulation installed etc.

The Garmin install was fine. Perhaps this was my ignorance but it would have been nice to have known about pending OH/Inspection items that could have been done while the plane is down and gutted. Being told you need to strip the interior 4 months after it was redone for the 5-year corrosion check is aggravating. While you have ABCD checks, you also have 3000Hr overhauls and 5 year items that are very heavy. I'll take the blame for not educating myself on that, though it would have been nice had the shop offered some guidance. Their response is "you didn't ask for that work" is true, but not helpful.

As you know, we also had the props condemned due to corrosion at the hubs. They were NOT due for OH. Not sure if that would typically been found in a pre-buy or not. I suspect a very thorough shop perhaps but not typical. We had a few parts that we found had not actually been OH and had to get a FAA waiver to move it for OH. This also wouldn't have been found in a pre-buy as they aren't verifying part numbers and just the log entry. So tack on a few weeks waiting on FAA paperwork.

Getting an OH/New hub was 3 months. Thats just parts availability. Then of course the shop had to put us back in the schedule once the hubs arrived.

Now, we are on the 3000/5 year check and the 8-week scheduled downtime is at 14 weeks and still going. Major delays have been:
Corrosion on skin panels - had to get some new panels/parts and repaint.
Toilet was cracked when reinstalled by the interior shop - had to get a new one of those and it took about 3 weeks.
Rudder Actuator OH - This is 60 days from Piaggio. Which we did plan for to get asap and get it back in the 8 weeks.
Flap Indicator - This was from inspection and now needs OH/replaced. Can't find a part and Piaggio is saying 70 days to OH.
Generator Duct - Needs to be replaced..its like 1ft section of aluminum dryer ducting....Piaggio says 120 days for the part....still looking for a used part.

Throw in some simple things like hoses etc that are 2-3 week lead times and it just keeps adding up. Some of this they work in parallel but others are only being found as we go.

I haven't even gone to FlightSafety yet. I've done maybe 3 flights in SIC seat down to move between shops etc. I'm hoping, we will be flying by Thanksgiving 22 and I can actually start enjoying this thing! If the Flap indicator goes from 70 days OH to 90 days OH it could be Christmas...or if we can't find that stupid generator duct/tubing it could be 2023. So far now, I keep burning holes in the clouds with my trusty A36.

TLDR: Delays are a combination of poor shop selection, maintenance items overdue/poorly maintained, and poor parts availability. Makes for a perfect storm of no flying.