180HP conversion & Vspeeds

[janetk]

I recently purchased a 52 C170B with the Avcon 180HP conversion and constant speed prop. I was told that I could use the C177 POH numbers on Vspeeds as a general guideline. Anyone with an opinion or addtional helpful information would be much appreciated.
Thank you,
Janet

[Jr.CubBuilder]

Ummmm like NO!
The V speeds are part of the airframe design they don't really have anything to do with the motor. It's still going to stall the same speed and you can still rip the tail off exceeding the original Vne.

There might be some argument that Vx and Vy would change a little, but my experience is that they don't, the extra power just increases your VSI reading your best airspeeds stay the same.

[amacbean]

Maybe they were referring to using the engine power settings for the 177, not the v-speeds? Just a thought.

[JHKeeton171]

Isn't the C177 the Cardinal? That is a completely different airframe and wing from the 170/172 series. I would think the fixed gear Cessna Cutlass (C172 with 180hp) would have more uselful info and data.

[blueldr]

Listening to whoever it was that gave you the informaion on using the "V" speeds of a C-177 is going to get someone killed.

[Green Bean]

Use the data in your 170B manual.. Same speeds, but your performance will be much improved. If you want Lycoming data, I could provide you with the Type certificate data in the original STC from Avcon. Each approved STC has its owned added information, according to the aircraft it is approved on. It should be added your aircraft flight manual.

[blueldr]

Green Bean,
To the best of my knowledge there is no "Flight Manual" for the C-170 series.

[Bruce Fenstermacher]

BL is splitting hairs. There is an Aprroved Flight Manual for the 170 but since it is a single sheet of paper it's not much a manual. It is a manual in the FAA's eyes jsut the same and any supplements should be keeped with it.

[Green Bean]

The latest revision to the Type Certificate Data Sheet No. A-799, which covers all Cessna 170's (170,A,B) is Revision 54, dated November 5, 2004. The data sheet (A-799 which is 14 pages) along with item 402.(a) "CAA Approved Airplane Flight Manual and pertinent revisions applicable to the particular model, serial number and landing gear installation" is required for flight. That means any approved modifications data information are part of the "Required Equipment" from page 6 of the TCDA Sheet A-799.

IMHO- One would interpret the Flight Manual to be the Cessna 170 Owners Manual that covers the basic aircraft information, from systems, operating check list, operating details, operating limitations (which are covered in the TCDS A-799, weight and balance, and lastly, operational data-called performance information, and the Type Certificate Data.

Now one calls it splitting hairs and another says there is nothing, but then maybe if you could call it common sense, and use all the data that is available, but that wouldn't include information data from a C177 Cardinal.

[Bruce Fenstermacher]

The key here is the word "approved". The owners manual, while good information, is not approved and therefor can not be the Approved Flight Manual (AFM).

Item 402 in the TCDS is a single piece of paper printed on both sides. Of course as we have already stated any additions from modifications would be added to that.

[Green Bean]

I will agree that it isn't required by the FAA, but the only data you have is what was demonstrated for the CAA certification for the aircraft and Cessna gives it to you in the form of a Owners Manual. The following statement is found in all of their aircraft manuals. "Cessna recommends that these items plus the Owners Manual be carried in the airplane at all times." Now if you didn't have that data, where are the V speeds coming from..? and where would you find the information to compute a weight and balance problem... Later this same data, became a required FAA manual, but I seriously doubt if you could get through a FAA check ride, without having a Cessna 170 Owners Handbook on board. So Bruce Your Arguing Semantics..

Lets see how did this discussion start? .... The question was what are the best V speeds,,, I got into this by recommending use the manual! It was answered by there isn't one..... from there it has gotten off track some... But the bottom line is that the Cessna 170 Owners Handbook, will give you most of the answers along with the data from the STC holders informational supplements that are added to each aircraft by the user/ owner...

[jrenwick]

... Later this same data, became a required FAA manual, but I seriously doubt if you could get through a FAA check ride, without having a Cessna 170 Owners Handbook on board. So Bruce Your Arguing Semantics...

From a regulatory point of view, this is certainly not semantics. The 170 Owner's Manual and the Approved Airplane Flight Manual (AFM) are two different things. The owner's manual has no regulatory standing; it is a marketing document. If an FAA inspector ever wrote you up for not having it in the aircraft, it would be a regulatory mistake. I've been through an FAA checkride recently, and yes, it was the AFM the examiner wanted to see -- not the Owner's Manual.

The AFM, if it exists for a particular aircraft type, is required to be in the aircraft at all times. That document (for the 170) is one double-sided sheet of paper, as Bruce correctly stated, and it bears the aircraft's N-number and the signature of the FAA Aircraft Division chief who approved it. It lists all airspeed limitations, i.e. the V-speeds, and other operating limitations. (The owner's manual should also list these, and maybe more.) This, along with required placards, is the "O" in the "AROW" mnemonic we use to remember the documents that must be on board an aircraft. The AFM actually lists items, like required placards, that might not be found in the Owner's Manual.

(Even older aircraft than 170s may have an "Operating Limitations" document, but no "Approved Flight Manual." My J3 is an example. This is perhaps why the mnenonic has an "O" instead of an "A".)

My own 170's AFM is reproduced here: http://members.iphouse.com/jkr/N4401B/AFM.pdf. This, rather than the Owner's manual, is the official source of V-speeds recognized by the FAA.

Best Regards,

John

[Green Bean]

Thanks for posting the AFM , John..

Keeping the original question in mind.. A 52 C170 with a 180 lyc installed.. How much of the 170 AFM is still accurate.?? since the very first statement under the AFM Limitations, , states....

"The following limitations are to be observed in the operation of this airplane as equipped with the six cylinder Continental C-145-2 engine".

Maybe for your aircraft N4401B, this two page AFM statement is okay,, Perhaps: Fuel System, Air Speed Limits, Flight Loads, Max Weight, CG Range, and some Placards. Aircraft with different engines or propellers, would the rest of the information be correct? Probably not, Should corrections be made to their AFM ? Yes. Can individual change the AFM, NO. but the addition of modifications are covered in the A-799 and STC data.

So maybe the two page AFM, is not totally correct, for every Cessna 170.?? Thats where 402a. with pertinent revisions applicable to the particular model,etc.

Interesting to note, that that the AFM data was written 4 years and 3 months, before your airplane was manufactured.

[jrenwick]

All 170Bs use the same AFM document -- the only difference is the N-number. So this document was created and approved when the 170B model was certified.

You're right, the new data for a 180hp conversion, if there are any, should be found in paperwork included with the STC. Many STCs include documentation that must be carried in the aircraft; these become legally part of the AFM. You still have to carry the original AFM, though, even if some of the information on it no longer applies.

John

[hilltop170]

John-
Thanks for posting your AFM. Has anyone gone thru the process of obtaining a replacement AFM from Cessna? I have flown this plane off and on from 1973 and have gone thru the logs more times than I can count. I have never seen an AFM for my plane. I wonder how many others need one as well?