The operating point shown is 210 KIAS, 422 KTAS, 1120 PPH, FL430, RAT -44, 3000 lbs fuel.

Estimating 1000 lbs cabin load, this is about 13,500 lbs operating weight.

Ram air rise is 23 C, making ambient air temperature -67 C, or ISA-10.

Book tables says this operating point is 207 KIAS, 413 KTAS, 1132 PPH, which is max cruise thrust, the pilot is flogging it. So the actual airplane is doing a touch better than book. Less fuel flow, slightly higher speed.

Under identical conditions, a straight V does 196 KIAS, 393 KTAS, 1012 PPH per book. About 6% better specific range at some loss in speed.

In this condition, N1 should be 99% on the Ultra. Appears there is some sort of indication problem, for both engines.

Mike C.

If the Ultra was slowed to the same IAS, would it not also have better specific range?

A tiny bit better for an Ultra slowed to 393 KTAS:

393 KTAS, 1003 PPH, N1 96%.

That is 1% better specific range than V going flat out.

The JT15D-5D engine is just a bit more efficient.

Mike C.

The operating point shown is 210 KIAS, 422 KTAS, 1120 PPH, FL430, RAT -44, 3000 lbs fuel.

Estimating 1000 lbs cabin load, this is about 13,500 lbs operating weight.

Ram air rise is 23 C, making ambient air temperature -67 C, or ISA-10.

Book tables says this operating point is 207 KIAS, 413 KTAS, 1132 PPH, which is max cruise thrust, the pilot is flogging it. So the actual airplane is doing a touch better than book. Less fuel flow, slightly higher speed.

Under identical conditions, a straight V does 196 KIAS, 393 KTAS, 1012 PPH per book. About 6% better specific range at some loss in speed.

In this condition, N2 should be 99% on the Ultra. Appears there is some sort of indication problem, for both engines.

Mike C.

yep. If you ever see a 99% N2 you have big problems....

Looking at the AOA, the barber pole, and some other panel shots I’m wondering if the camera captured an anomaly. The Ultra N2 is limited at 97%. Mike also noted we were beating book numbers. I bet we flew through a bit of an updraft and that got captured.

N1 is limited at 99 iirc (docs say 100 but this jet was placarded 99). 98 until you accelerate then you can add 1% more. Its either 97/98 or 98/99. Not sure at the moment. “Old” guy memory.

My bad, thought N1 was core, N2 fan, but that's backwards (which seems odd given N2 drives N1...).

Mike C.

Ultra AFM says, in limitations, N1 100%, N2 97%.

For N1, says "Refer to the appropriate thrust setting charts in Section IV, STANDARD CHARTS, for % FAN RPM setting.".

That chart only shows allowed values to 99%.

When you look through the cruise tables, I don't see any numbers over 99%.

The AFM further gives this guidance on N1 overspeed:

The basic take away is don't go over 99%, but you got 1% margin to where engine damage starts.

Mike C.

This picture is from today's flight. I had just leveled at 450 and was burning 98GPH and doing 370Kts. As I burned off fuel, we accelerated to 398Kts.

What would the Ultra burn up at 450?
What speed?

At 13,000 lbs (roughly mid cruise, say), FL450, ISA, book says:

MCT: 404 KTAS, 974 PPH, 145 GPH
LRC: 364 KTAS, 813 PPH, 121 GPH

For 372 KTAS and ISA+3 as shown in your picture, it is about 836 PPH, 125 GPH. 28% more fuel for an airplane that is 32% heavier, not too bad really.

Mike C.

The operating point shown is 210 KIAS, 422 KTAS, 1120 PPH, FL430, RAT -44, 3000 lbs fuel.

Estimating 1000 lbs cabin load, this is about 13,500 lbs operating weight.

Ram air rise is 23 C, making ambient air temperature -67 C, or ISA-10.

Book tables says this operating point is 207 KIAS, 413 KTAS, 1132 PPH, which is max cruise thrust, the pilot is flogging it. So the actual airplane is doing a touch better than book. Less fuel flow, slightly higher speed.

Under identical conditions, a straight V does 196 KIAS, 393 KTAS, 1012 PPH per book. About 6% better specific range at some loss in speed.

In this condition, N1 should be 99% on the Ultra. Appears there is some sort of indication problem, for both engines.

Mike C.

Slight drift...What are the requirements to act as SIC in a 560XL?

Three take offs and landings as well as a half day ground school. Multi engine. Not that big a deal.

https://www.law.cornell.edu/cfr/text/14/61.55

That was quick. Thanks MH

61.55 (b) Except as provided in paragraph (e) of this section, no person may serve as a second-in-command of an aircraft type certificated for more than one required pilot flight crewmember or in operations requiring a second-in-command unless that person has within the previous 12 calendar months:

(1) Become familiar with the following information for the specific type aircraft for which second-in-command privileges are requested—

(i) Operational procedures applicable to the powerplant, equipment, and systems.

(ii) Performance specifications and limitations.

(iii) Normal, abnormal, and emergency operating procedures.

(iv) Flight manual.

(v) Placards and markings.

(2) Except as provided in paragraph (g) of this section, performed and logged pilot time in the type of aircraft or in a flight simulator that represents the type of aircraft for which second-in-command privileges are requested, which includes—

(i) Three takeoffs and three landings to a full stop as the sole manipulator of the flight controls;

(ii) Engine-out procedures and maneuvering with an engine out while executing the duties of pilot in command; and

(iii) Crew resource management training.