Certification vs Operation

[GravityHater]

I gather it is like this:
You can have an airplane that is Certified under the Pt 25 rules
But that same airplane is Operated under Pt 23 rules.
T or F?

I know I have this screwed up, all the wording can be confusing to a non-lawyer like me.

Like John Travolta's jet... does he need to fly it to meet the Transport Category rules. It was certified under pt 25 but he is pt 91... so 25 doesn't apply, only 23?

 

[minitour]

I'd think 25 would still "apply"...you're using a plane "certified" under Pt 25...whether you operate under 135, 121, 125, 91...doesn't matter...it's a 25 airplane.

...at least that's my guess....

avbug will probably know...he's good at this stuff

-mini

 

[gern_blanston]

It's the airplane that's Part 25, not the operation, so the airplane must be operated as a Part 25 machine all the time.
Seems like our old KingAir 300 was dual-certified: Part 23 below 12,500# and Part 25 Above 12,500#. So you had to have balanced-field for the over 12,500# takeoffs but not under. Does that sound right anyone?

 

[GravityHater]

So an airplane can be certified to the levels required by pt25... but never actually need them in a legal sense because it is operated under pt 91?

 

[gern_blanston]

If it's a Part 25 airplane, I believe you're required to fly it per Part 25. Doesn't matter whether you're operating under 91 or 135.

 

[midlifeflyer]

I'm lost on the question.

FAR 1.1 (and the basis for more than one question on the private plot knowledge test):

==============================
Category:
(2) As used with respect to the certification of aircraft, means a grouping of aircraft based upon intended use or operating limitations. Examples include: transport, normal, utility, acrobatic, limited, restricted, and provisional.
==============================

Part 25 deals with the rules for building and certifying transport category aircraft.

If the airworthiness certificate says "transport" it means that the airplane was built certified and tested in accordance with part 25 standards.

Like all other aircraft, the airplane has to be operated in accordance with it's limitations that are established under its certification rules and those written into it TCDS and AFM.

I'm not sure what that has to do with whether the airplane is operated for personal use under Part 91 or for hire under Part 135 or in an air carrier operation under Part 121.

(There may be some Part 125 issues because the seating capacity is more than 20)

Perhaps I'm misundersatnding the question. Can you point out some requirment in the certifciation rules that you think might apply depending on the type of operation the aircraft is used in?

 

[GravityHater]

Can you point out some requirment in the certifciation rules that you think might apply depending on the type of operation the aircraft is used in?

How about the t-o and climb requirements. The a/c is certified to pt 25 standards meaning all the charts give the minimum rwy length and climb requirements for each segment. But as a pt 91 operator are you bound to ensure they are used or followed?
So John Travolta has an airplane with t-o, first, second, third and final segment climb minimums built in, the charts all say so but he does not have to ensure the rwy length is there, the climb requirements are satisfactory (except as required by any rules in pt 91)?

 

[gern_blanston]

But as a pt 91 operator are you bound to ensure they are used or followed?

Yes. It's pretty simple. Yes.

 

[Publishers]

The aircraft is a Part 25 aircraft

The way it is operated is Part 91

The books used in operation thereof are based on certification part.

 

[GravityHater]

Roger, over and out!

 

[midlifeflyer]

How about the t-o and climb requirements. The a/c is certified to pt 25 standards meaning all the charts give the minimum rwy length and climb requirements for each segment. But as a pt 91 operator are you bound to ensure they are used or followed?

I think your answer is in Part 25 itself. Subpart G deals with operating limitations. Just one of them :

==============================
§ 25.1533 Additional operating limitations.
(a) Additional operating limitations must be established as follows:
(1) The maximum takeoff weights must be established as the weights at which compliance is shown with the applicable provisions of this part (including the takeoff climb provisions of § 25.121(a) through (c), for altitudes and ambient temperatures).
(2) The maximum landing weights must be established as the weights at which compliance is shown with the applicable provisions of this part (including the landing and approach climb provisions of §§ 25.119 and 25.121(d) for altitudes and ambient temperatures).
(3) The minimum takeoff distances must be established as the distances at which compliance is shown with the applicable provisions of this part (including the provisions of §§ 25.109 and 25.113, for weights, altitudes, temperatures, wind components, runway surface conditions (dry and wet), and runway gradients) for smooth, hard-surfaced runways. Additionally, at the option of the applicant, wet runway takeoff distances may be established for runway surfaces that have been grooved or treated with a porous friction course, and may be approved for use on runways where such surfaces have been designed constructed, and maintained in a manner acceptable to the Administrator.
(b) The extremes for variable factors (such as altitude, temperature, wind, and runway gradients) are those at which compliance with the applicable provisions of this part is shown.
==============================

Bottom line is simple: No matter what rules you are operating under, you =always= have to fly within the aircraft's operating limitations. Even under Part 91:

==============================
§ 91.9 Civil aircraft flight manual, marking, and placard requirements.
(a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.
==============================

 

[avbug]

The confusion is between certification standards, and operating rules. There is no correlation.

You must comply with published limitations. A performance chart shows what the aircraft can do under a specific set of circumstances, and one would be foolish not to avail one's self of that information if accurate...but it's not necessarily a limitation.

Weather the aircraft is certificated under Part 23 or Part 25 is largely irrelevant to how you operate it, as neither are operating rules. Both Parts 23 and 25 are standards which must be met by the aircraft in the certification process. What you do with it is up to you, within certain bounds.

 

[ackattacker]

You must comply with published limitations. A performance chart shows what the aircraft can do under a specific set of circumstances, and one would be foolish not to avail one's self of that information if accurate...but it's not necessarily a limitation.

Except that midlifeflyer has just shown as that takeoff distance is a *limitation* which must be established by the manufacturer. For transport category aircraft that information will be in terms of balanced field length, not actual takeoff roll.

Also lets not forget 91.103 on preflight action:
91.103(b)(1) For civil aircraft for which an approved Airplane or Rotorcraft Flight Manual containing takeoff and landing distance data is required, the takeoff and landing distance data contained therein; and

 

[avbug]

Negative...minimum takeoff distances are limitations, reference Part 25. Balanced field lengths are not necessarily limitations, nor are many of the published takeoff distances. Be careful not to confuse published performance data with aircraft limitations.

 

[FOD]

Negative...minimum takeoff distances are limitations, reference Part 25. Balanced field lengths are not necessarily limitations, nor are many of the published takeoff distances. Be careful not to confuse published performance data with aircraft limitations.

So say it is 40C outside and my performance charts only go to 35C and I took off, would I be breaking the Regs and operating outside of the limitations?

 

[midlifeflyer]

So say it is 40C outside and my performance charts only go to 35C and I took off, would I be breaking the Regs and operating outside of the limitations?

If the data also constitutes a limitation, yes. If the data does not constitute a limitation, no.

 

[FOD]

If the data also constitutes a limitation, yes. If the data does not constitute a limitation, no.

Ok maybe this is a dumb question, but how do you know if it "constitutes a limitation"?

 

[ackattacker]

Negative...minimum takeoff distances are limitations, reference Part 25. Balanced field lengths are not necessarily limitations, nor are many of the published takeoff distances. Be careful not to confuse published performance data with aircraft limitations.

Well I'm certainly confusing something, namely my overworked and underpaid brain.

Correct me if I'm wrong, but the wording in 25.1533 leads me to believe that the takeoff distance limitation includes the performance requirements of accelerate-stop, climb, etc.

The wording is "The minimum takeoff distances must be established as the distances at which compliance is shown with the applicable provisions of this part (including the provisions of §§25.109 and 25.113, for weights, altitudes, temperatures, wind components, runway surface conditions (dry and wet), and runway gradients) for smooth, hard-surfaced runways.

25.109 is accelerate stop, 25.113 is takeoff distance and takeoff run. So at the very least the takeoff distance limitation must include accelerate-stop, and it appears that "the applicable provisions" could be interpreted to include 25.111 takeoff flight path, 25.121 climb: one engine inoperative, etc.

Out of curiosity, I pulled out the A.F.M. for the ATR-42 (the only part 25 airplane I'm familiar with). The limitations section of the manual doesn't spell out anything about takeoff distance other than to say that "Performance Configuration - The aircraft configuration provided in section 6 must be observed". and "Maximum takeoff weight and maximum landing weight may be reduced by performance requirements related to the following (see chapter 6)" then goes on to list climb performance gradients, runway length, tyre speed, brake energy limit, obstacle clearance (takeoff and enroute) etc.

So this leads me to believe that the performance data in chapter 6 constitutes limitations, since they are explicitly reference in Chapter 2 (limitations). And the performance data in Chapter 6 (pages and pages of it), includes all kinds of graphs for every conceivable thing except a normal both engines operating takeoff. The "Takeoff Run" and "Takeoff Distance" graphs are both for "one engine feathered, one engine at R.T.O. power after critical engine failure - air conditioning off - anti-ice/deice off - no runway slope - no wind".

 

[midlifeflyer]

Ok maybe this is a dumb question, but how do you know if it "constitutes a limitation"?

It's actually a pretty good question.

One way is pretty obvious: it appears in the Section 2 of the modern AFM - "Limitations." Quick example from even small aircraft. Is the weight and balance chart a limitation or advisory? Well, if you go to Section 2, you will see that the weight and CG limits are given there also. (Note ackattacker's most recent post about the Section 2 reference to the performance data).

Another is the TCDS (Type Certificate Data Sheet). Yup, you'll usually find the information there also.

A third is the certification rules themselves. As we've seen, some specifically say they are limitations; others don't. It's subpart G for both Part 23 and 25, you can put them side by side and see the differences. You'll see that the language making the takeoff performance dataa limitation that appears in Part 25 does not appear in Part 23.

One more. Perhaps not really a limitation in the technical sense, and may even be a little vague at times, but definitely one in a practical sense. (This one could probably be an entire thread by itself). Watch out for AFM operating instructions are given in mandatory terms. There is NTSB case law holding that doing things like skipping a checklist item violates 91.9. The problem here might be deciding what is mandatory and what is just informational (the famous C172 'slips with flaps' argument).

Most of the time, for most of us, it will be a combination of Section 2 with a dose of the "mandatory instruction" problem.

 

[Wasted]

So say it is 40C outside and my performance charts only go to 35C and I took off, would I be breaking the Regs and operating outside of the limitations?

The chart is not where the limiation is found. The limitation you would violate is the one in the limitations section that says maximum temperature is 35C.