Clarifications on airfield performance
Hi Folks
I would like to post some clarifications on the very interesting discussion develloped here.
I like first to assure everybody that AW189 has been certified and is fully compliance with all the applicable rules and no exemptions have been made.
H-V
In AW we are convinced that the CS29 H-V regulations, particularly for twin engines is out of date and needs to be revisited in order to provide a much more practical and operational information.
The traditional H-V chart does not provide much to the operator other than data for which a potential HOGE engine failure could be catastrophic without providing a real operational scenario and way out procedures. Furthermore traditional H-V charts are only valid for the type of published surface that is usually a runway type that is almost never the situation for takeoff/landing and OGE operations in real life.
For this reason we went for a "non traditional" H-V charts that in our opininon provide what a pilot needs to know when is hovering OGE (IGE section is automatically incorporated in the Cat B and Cat A takeoff and landing procedures/WAT).
We do hope that this way of presenting H-V data will be welcomed by the operators and AAs as well (EASA has already).
Cat B
The published Cat B procedures fully comply with the requirements for the takeoff profile up to 50 ft and climbout speed and for the OEI Continnuous climb performance requirements. The published WATs cover these procedures for zero wind takeoff/OEI landings, for any wind effect, dedicated WAT charts are published for both HIGE (takeoff and landings) an HOGE.
The published procedures cover both HIGE depart style and rolling takeoff from available runways.
Cat A
We currently pubblished only Runway, and ground/elevated helipad (including a shallow landing approach to allow more weight when feasable).
For the Runway (Clear Area) we elected to provide a rolling style manoeuver for a very simple reason:[LIST][*]our helicopters have wheels, why not use them?[*]this technique is much more passanger friendly[*]If an engine fails before lift off, no big deal
But we are also open to provide a traditional HIGE depart if this would be required even though a Cat A reject must always be demonstrated on a suitable surface that can accomodate it that is usually a runway for this kind of procedure.
The vertical helipad procedure is provided for helipad size of at least 20x20 m and can easily be accomplished with always the ground in sight. 110 ft is considered safe and easy to achieve. This manoeuver is very passenger friendly in all phases and not aggressive in case of any emergency.
This procedure is meant for ground base helipads.
The shallow helipad approach is a traditional helipad landing style
As per our company attitude, we will be providing also a dedicated offshore helideck Cat A procedure (like the 139) that will be certified a later date.
I hope this helps in understanding the reasons behind the 189 procedures/performance and opens a profitable discussion.