Jim,

 

I'm with ya............  Where do we look for a definition of the criteria: "maximum cruising speed?"  If I apply takeoff power in level flight I will exceed 180 KCAS but I am sure not "cruising" there.  If I use the definition of "cruise" as a level flight speed where fuel is used efficiently.  Then aren't I at less than 75% power (no matter how I got there and whatever that means if full power is unknown) and operating LOP?  That certainly puts me below 180 KCAS. 

 

Can 100% "power" be defined as "best power (say 150 degrees ROP) at some MSL at a certain fuel consumption, rpm and prop efficiency yielding a KCAS - then translated to Sea Level equivalence?  That would be so I could compute 75% power with adjustments for altitude and temp along with KCAS for those conditions.  Then I would know what size the N-numbers should be.

 

In other words, is there a national FAA acceptable definition of Vc?

 

Scott AKA Grayhawk

 

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=70147eedbfce0d8e20b5db33242f19c4&rgn=div8&view=text&node=14:1.0.1.3.22.3.363.6&idno=14

 

1                     Go to www.faa.gov

2                     Click on Regulations and Policies Tab

3                     Click on FAA Regulations

4                     Click on Current Federal Regulations

5                     Click on 1-59

6                     Click on 45.1-45.33

7                     Click on 45.29

8                     Look at (b) 1 (ii)   “…3 inches high may be displayed…when the maximum cruising speed of the aircraft does not exceed 180 knots CAS;…” 

 

Without a Letter from your FSDO for your specific N number, you are clearly directed by the text.  Call or visit your FSDO or MIDO. 

 

Remember, your program letter with your application, if you use a preformatted one, says that you marked your aircraft I/A/W FAR 45.

 

Operating Limitation Number 1, issued on day of Certification, states that you are to comply with all of FAR 91.   FAR 91.9 (c) says that you must be ID’d Via …”part 45 of this chapter”.  This is further defined again around Operating Limit (13) …” This aircraft must contain the placards, markings, etc., as required by §91.9”.

 

So, unless you have an individual Letter, in your possession, to deviate from the included texts, I’d say the text is pretty clear.

 

You can do anything with a Clearance.  Just because someone else is running afoul of their specific Operating Limits, and the FAR, does not make it OK for us to repeat their intention.

 

Bottom line is that you’ve got to have a separate letter, or a statement built into your Operating Limits, to not violate all of the above.  This subject is not new nor has it been changed in the last 20 years.  Be careful out there.

 

Jim

 

 

 

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From: Ed Gray [mailto:egraylaw@swbell.net]
Sent: Monday, June 13, 2011 6:50 AM
To: lml@lancaironline.net
Subject: N numbers

 

My understanding was numbers should be one foot high if plane exceeds 200 knots, but I have seen many 360s with 3 inch numbers, and am sure these are 200 knot planes.  I plan on a little over 200 knots, what should I do?

Ed Gray, Dallas L2 building