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Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 10, 2021 2:27 pm
by CaptRawData
I'm aware that for Commerical Air Transport (CAT) there is a class B classification of performance.

If that type of aircraft is then used in let's aerial survey work (Part Spo) then are the performance req the same or different due to it not being specifically Air Transport.

For instance under CS23, a King Air B200 for CAT is Class B performance.

Due to a modification and change of operation ie survey work the aircraft is then longer cs23 Normal but is cs23 Commuter.

Other than the lesser amount of Positive /negative G from the different weight limit is there any change to the perf req of that B200 in that example?

Any advice or where to possibly find such info would be greatly appreciated

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Wed May 12, 2021 5:25 pm
by CanukinUSA
Have you looked at CS-23 and EU-OPS on the EASA internet site?

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Thu May 13, 2021 7:37 am
by zeke
CaptRawData wrote:
I'm aware that for Commerical Air Transport (CAT) there is a class B classification of performance.

If that type of aircraft is then used in let's aerial survey work (Part Spo) then are the performance req the same or different due to it not being specifically Air Transport.

For instance under CS23, a King Air B200 for CAT is Class B performance.

Due to a modification and change of operation ie survey work the aircraft is then longer cs23 Normal but is cs23 Commuter.

Other than the lesser amount of Positive /negative G from the different weight limit is there any change to the perf req of that B200 in that example?

Any advice or where to possibly find such info would be greatly appreciated


Performance would be different to air transport.

As far as category go, it can remain normal or even utility. For such a modification there will be a flight manual supplement as part of the STC, and they normally reduce the maximum allowable weights so loads are not exceeded.

Really need to see that supplement to know the specific limits on that airframe.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Thu May 13, 2021 3:20 pm
by CanukinUSA
I am puzzled as to why using the aircraft for survey would cause the aircraft to now be a commuter category aircraft? One would think it would be a normal category aircraft and only be a commuter aircraft when used for Commuter Airline use with passengers. Are you certain that your interpretation is correct?
The aircraft would require better engine-out performance when used as a Commuter aircraft than a normal category CS-23 aircraft due to the number of passengers now that could be carried.
I am not familiar with EASA regulations very well but one would think that the CS-23 Commuter standards would be similar to the old SFAR-23 standards that were in effect in the US a few years ago which were in between 14 CFR Part 23 and 14 CFR Part 25 to enable smaller aircraft to be used for Commuter airlines even through they did not meet the tougher standards for a Transport Category aircraft.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 9:41 am
by CaptRawData
zeke wrote:
CaptRawData wrote:
I'm aware that for Commerical Air Transport (CAT) there is a class B classification of performance.

If that type of aircraft is then used in let's aerial survey work (Part Spo) then are the performance req the same or different due to it not being specifically Air Transport.

For instance under CS23, a King Air B200 for CAT is Class B performance.

Due to a modification and change of operation ie survey work the aircraft is then longer cs23 Normal but is cs23 Commuter.

Other than the lesser amount of Positive /negative G from the different weight limit is there any change to the perf req of that B200 in that example?

Any advice or where to possibly find such info would be greatly appreciated


Performance would be different to air transport.

As far as category go, it can remain normal or even utility. For such a modification there will be a flight manual supplement as part of the STC, and they normally reduce the maximum allowable weights so loads are not exceeded.

Really need to see that supplement to know the specific limits on that airframe.


Yeah I guess outside Commerical air transport (CAT) part b Perf doesn't apply

There is an stc/ supplement info on the two modified aircraft. The mod puts them over the 12500 lbs hence it moves from normal into utility category and hence the g limits are different due to increase of weight

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 9:43 am
by CaptRawData
CanukinUSA wrote:
Have you looked at CS-23 and EU-OPS on the EASA internet site?



Yeah I have but couldn't find a clear answer on either what perf applies to non commercial air transport with props and also the easa is a complete nightmare to research through, in my opinion at least

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 9:47 am
by CaptRawData
[quote="CanukinUSA"]I am puzzled as to why using the aircraft for survey would cause the aircraft to now be a commuter category aircraft? One would think it would be a normal category aircraft and only be a commuter aircraft when used for Commuter Airline use with passengers. Are you certain that your interpretation is correct?
The aircraft would require better engine-out performance when used as a Commuter aircraft than a normal category CS-23 aircraft due to the number of passengers now that could be carried.

My understanding is that it's the weight from the modification that take the two aircraft over the 12500 lbs which is the limit for a normal category of aircraft and not related to the role of the aircraft in this instance

In relation to performance, I can only find reference to CAT B perf which is written for commerical air transport.

What performance standard relate to any type of airplane when it's not being used for CAT? Or does it relate to certification of the aircraft ie Cs23 and cs25?

I'm thinking in the likes of John Travolta with his personnel 707. It's a cs25 jet or the old equivalent of that maybe. Did he need to adhere to perf a performance even if the aircraft was being privately?

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 12:50 pm
by CanukinUSA
There are two aircraft performance standards that have to be considered for an aircraft.
1) There is the performance standard that the aircraft was required to meet so that it can obtain a type certificate (“Airworthiness Standard”). This is what the regulator and potential manufacturer agree on when an Aircraft project is started. The manufacturer has to meet the standard to get the aircraft a type certificate in their country. They may later have to get a type certificate in other countries to allow operators in those countries to buy and operate the aircraft depending on international agreements between the countries.
2) There is the performance standards that have to be met to operate it legally (“Operational Standards”). This depends on how the aircraft is operated and on the regulations the country requires for aircraft operation.

The 707 is probably not a good example to use as it was probably certified long before cs25 existed. My guess is it was under the CAR 4B airworthiness standard but I will have to check the Type Certificate Data Sheet on the FAA internet site to confirm that. That was before the 14 CFR Part 25 (aka FAR Part 25) existed. JAR Part 25 was based on FAR Part 25 and as far as I understand cs25 is an update from it.
As far as John Travolta’s 707 goes if I recall correctly it was US registered and as a private aircraft would operate under 14 CFR Part 91 and maybe under 14 CFR Part 125 depending on how he legally operated it.
He was not operating it as a commercial aircraft and as a result would not operate under the Air Carrier Regulations ( 14 CFR Part 121 or 14 CFR Part 135) as far as I know. If he decided to operate it using the Air Carrier regulations that would be his call and not a legal requirement. There are aircraft performance regulations in these parts that he would be required to operate under. Obviously the standards are stricter as more people are involved and at risk and when it is operated as a commercial operation.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 1:09 pm
by GalaxyFlyer
Travolta’s plane had to be under Part 125, more than 19 seats or payload greater than 6,000#. It’s sort of mix of private and commercial standards. Planes have to operated in accordance with their AFM, regardless of operating regulations, which for current Part 25 types requires all the performance calculations as an airline would operate, esp runway analysis. I think that’s called Perf A.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Mon May 17, 2021 2:06 pm
by CanukinUSA
Not necessarily. I flew for an Air Taxi Part 135 operator for a few years and we were legally allowed to operate ferry flights to position for commercial flights using Part 91 rules which allowed the landing distances to be calculated without the 60% factor. I did not totally agree with that but it was perfectly legal. One of those loopholes in the regulations I assume. There is additionally no obstacle analysis after takeoff required for a Part 91 operator. It is legal but I think most of us would agree that it is of very questionable safety.
I just retired from a major aircraft manufacturer in the Pacific Northwest and we operated our large aircraft under 14 CFR Part 91 rules not 14 CFR Part 125 rules most of the time.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Fri May 21, 2021 6:43 am
by CaptRawData
CanukinUSA wrote:
There are two aircraft performance standards that have to be considered for an aircraft.
1) There is the performance standard that the aircraft was required to meet so that it can obtain a type certificate (“Airworthiness Standard”). This is what the regulator and potential manufacturer agree on when an Aircraft project is started. The manufacturer has to meet the standard to get the aircraft a type certificate in their country. They may later have to get a type certificate in other countries to allow operators in those countries to buy and operate the aircraft depending on international agreements between the countries.
2) There is the performance standards that have to be met to operate it legally (“Operational Standards”). This depends on how the aircraft is operated and on the regulations the country requires for aircraft operation.


That's great cheers

So would cs23 and cs25 relate more to the airworthiness standard or operational standards or a mix of both?

From what I can make out In cs23 it talks about commuter etc as a separate section to Normal cs23

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Fri May 21, 2021 9:18 am
by CanukinUSA
cs23 and cs25 are airworthiness standards like 14 CFR (FAR) Parts 23 and 25 in the US.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Fri May 21, 2021 11:03 am
by CanukinUSA
Not being an expert on EASA regulations, that appears to be similar to what used to be Special Part (SFAR) Part 23 which were temporary standards for commuter aircraft that were in place when the commuter airlines in the US started to expand rapidly using aircraft with greater then 9 up to 19 seats and 19000 lbs maximum weight that did not meet the airworthiness standards for Transport Category aircraft (14 CFR Part 25). Part 23 aircraft cannot have more then 8 seats and must be below 12500 lbs Maximum weight except for commuter aircraft that wee certified under SFAR Part 23. SFAR Part 23 does not exist anymore so you could not Certify an aircraft in accordance with it but there are still aircraft in operation that were certified under SFAR Part 23.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Fri May 21, 2021 8:31 pm
by CanukinUSA
Correction: I just looked up the rules currently for SFAR Part 23 applied to aircraft with Passenger Seats of 10 to 19 passengers and up to 12,500 lbs MTOW. Not 19,000 lbs as I stated in a previous post.
For all the details for aircraft performance from the FAA please check the "Flight Standards Information management System" FAA Order 8900.1, Volume 4 Aircraft Equipment and Operational Authorizations, Chapter 3 Aircraft Performance and Airport Data, 4-527 Small Non-Transport Category Airplanes with 10 to 19 Passenger Seats and Up to 12,500 MTOW at:
https://fsims.faa.gov/PICDetail.aspx?do ... 3,Sec2_SAS
My guess is that the EASA Operational requirements are very similar due to harmonization with the FAA. It is just a question of how EASA interprets the rules in their regulations.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Fri May 21, 2021 8:59 pm
by CanukinUSA
Another correction: There was a Special FAR (SFAR) Part 41 for Turboprop and Jet Aircraft up to 19,000 lbs. which like SFAR Part 23 cannot be used anymore for Aircraft Certification. So I was not completely incorrect in mentioning 19,000 lbs.. For details go to the previous post link from the FAA.
As you can see figuring out which performance standard you need to operate under is not simple. I am certain that EASA adds more complexity on top of the FAA rules with their standards.

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Sat May 22, 2021 1:20 am
by CanukinUSA
Section 1 of Chapter 3 above helps in understanding the performance operational requirements from the FAA
For details go to:
https://fsims.faa.gov/wdocs/8900.1/v04% ... 03_001.pdf

Re: Class B Performance and Cs 23 Normal / commuter

Posted: Sat May 22, 2021 1:27 am
by MO11
Or -

FAR 23 Commuter Category applies to airplanes with 19 seats or less, with MGTOW of 19,000 lbs or less. Think Metro 23.

SFAR 23 applies to normal category airplanes that have 10 or more seats and weigh 12,500 or less and operate under FAR 135. Think Beech 99 or Bandeirante.

SFAR 41c became FAR 23 commuter category.