Heli Performance standards

[V12]

Could someone either simply explain (or provide a link to where I can read about) the different categories of performance that apply to public transport operations in the UK. I have heard, but don't understand, the expression Performance A, for example. What is the correct terminology for the different levels of standards from PPL(H) Private to fully Twin IFR offshore. Clearly paying money to hire a helicopter from a CAA approved carrier means higher standards will apply on various criteria.

Thanks

[Barndweller]

Trying to put it simply and in plain English (yes i know it's not word for word so don't jump on me too hard).

Performance Categories A and B refer to older pre JAA legislation that may still be relevant in some cases.

The more commonly used criteria are the JAA performance Classes One, Two and Three.

Performance classes one and two apply to only twin engine helicopters whilst perf' class three may apply to twin or single engine helicopters.

If operating in performance class one, the helicopter must be operated in such a way as to ensure that, in the event of the failure of an engine, the helicopter can either continue with flight or carry out a safe landing (note landing not forced landing). (this is loosely aligned with the old Cat' A)

PC 2 accepts that rather than carrying out a landing, a forced landing may be necessary.

PC3 accepts that a forced landing will be necessary (obvious in the case of a single engine helicopter). (Approximate to old Cat' B)

Definitions (roughly).

"Landing": Basically, the helicopter will return to the ground on a suitable surface and land without any damage (although it's generally accepted that some damage to brakes and tyres is allowed for wheeled helicopters). An example of such an area would be a runway or a clear flat grass area with no obstructions.

"Forced Landing": the helicopter may land in an area less well suited and may sustain some damage but there must be the reasonable expectation that there will be no serious injuries to the occupants. There must be no damage to persons or property on the ground. An example of this might be ditching on water or running through a hedge or other obstacle that would damage the helicopter but not affect the occupants. A forced landing is definitely not a "crash" it must be fully controlled with consideration given to the area being used.

As for what an operator is required to operate to:

It very much depends... In the case of UK onshore Public transport i believe that an operator may operate down to PC3 (it will depend on what they have specified in their Operations Manuals) although there will be circumstances when PC 1 is required - for example operating in a congested area like a town or city or in a "hostile environment" where a due to terrain or location a safe forced landing cannot be made. Outside of areas where the CAA insist on PC1 for the above reasons it will be up to the customer to check / specify the performance class available / required.

As for non public transport - well they're allowed to "crash" but they must do it without damage to persons or property on the ground.

Hope that's useful - i now wait to be picked to bits.

Cheers
Barny

[V12]

Thanks for raising your head above the parapet, Barndweller; thorough and much appreciated. Educational!

[Hullaballoo]

this is loosely aligned with the old Cat' A

To be clear: Cat-A is an airworthiness criteria, used in certification of the aircraft. The Cat-A standards include: (1) multi-engine design, in addition to engine/system isolation (which ensures that failure of one item won't result in failure of the remaining systems); (2) OEI performance, which allows for continued safe flight and landing; and (3) scheduled procedures for takeoff and landing (to include WAT limits).

To be PC-1, you must also have Cat-A design ... without this design, there's no way to guarantee that you can "operate the the helicopter in such a way as to ensure that, in the event of the failure of an engine, the helicopter can either continue with flight or carry out a safe landing."

Clear as mud!

[Barndweller]

Hullaballo is quite correct - where is said "Category" A and B please replace with "Group" A & B - Which refers to the older performance criteria.

Apologies for the confusion - The memory is the first thing that ...erm......... goes......

Barny

[spinwing]

Mmmmm ...

Funny I was under the impression the Airworthiness criteria were Class A or B type aircraft.


That Cat A (or B) were procedures which would allow a Heli to be able account for its performance be it Performance 1, 2, 2e or 3.


Obviously lots of confusion out there (me too).

[212man]

Nope, Class A and B are drugs, Cat A and B are certification criteria laid down in FAR Part 29 and EASA CS-29 (formerly JAR-29.)

The performance standard required for a particular Comercial Air Transport operation will be a function of the number of seats approved for the operator's aircraft, plus the environment being operated in (hostile, congested etc.). Basically, the more seats the higher the standard required, and the more unforgiving the environment the higher the standard required.

If you want to find out more, you should look up JAR OPS-3 sections F, G and H.

[spinwing]

Mmmm ...

212man ....

Arrrr .... you see this is where it gets tricky ... 'cos Australia for instance Class A or B is in fact an Airworthiness classification which determines HOW you aircraft shall or may be maintained.


Do have JAR 3 (electronic version) find it excellent for sleeping problems!

..... and that might be my problem :}


Class A or B Drugs ... I think is a UK classification only .... :confused:

[paco]

More mud for the pool:

As stated, the Category concerns airworthiness.

The Performance Class determines the outcome after an engine fails, by ensuring that a safe margin exists between what the helicopter is able to achieve and what it is required to achieve.

Helicopters with more than 19 passenger seats, or operating to or from heliports in congested hostile environments, must operate under Subpart G of JAR OPS 3 (Performance Class 1). Helicopters with 9-19 passenger seats may operate under Subpart G or H (1 or 2). Helicopters with 9 or less passenger seats may operate under Subpart G, H or I (1, 2 or 3), although a single-engined helicopter will automatically come under Subpart I (Class 3).

Perf 2 is a mixture of 3 and 1, in that, you are Class 3 until you reach a point where you can maintain Class1 Preformance (the DPATO). This means that you must be visual with respect to obstacles till that point (600 ft cloudbase, 800 m vis), and is why machines such as the 212 still require floats.

Category A helicopters may operate in Performance Class 1, 2 or 3. Category B machines must operate under Class 3. However, Performance Class 1 and 2 helicopters must be certificated in Category A, and Class 3 helicopters may be certificated in Category A or B, but only used in non-hostile environments, to give them more choice of reject areas. HEMS aircraft greater than 5 700 kg must operate under Class 1.

Phil

[spinwing]

Mmmm ...

Thank you Phil ....

Didn't think I had completely lost it ..... YET!

:E

[paco]

Just found out that HEMS can now opereate to PC2, regardless of weight

Phil

[212man]

Spinwing, the classes you refer to are indeed airworthiness classifications, but they apply to continued airworthiness, not type certification. CASR 29 deals with that, but effectively refers the reader to FAR Part 29.

Part of the confusion arises from the fact that the procedures used to demonstrate the Cat A performance standards - and published in part 1 of an RFM - are often used to comply with the PC1 requirement imposed by OPS-3 ( and ICAO Annex 6.). Further complicated by the previous use in the UK of the term Group A for the operating standard!

[spinwing]

Mmmm ....

Yes .... agreed .... doesn't really help 'new chums' trying to understand things though does it!


:eek: