AgustaWestland, EASA Explore Safe Reject Approach

[megan]

From Aviation International News

AgustaWestland and EASA are discussing a new approach to the height-velocity (H-V) diagram for multi-engine helicopters, proposing to replace it with “safe reject” indications. They advocate adopting the idea of “fly away” in case of engine failure to make the most of the helicopter’s performance rather than relying on a diagram that shows operators what not to do. With the fly-away maneuver, the pilot determines a flightpath that keeps the aircraft clear of obstacles.

Bernardino Paggi, an AgustaWestland expert in flight-test methodologies, identified this common misconception: “If I fly outside the H-V area, I am always safe.” In fact, he said, a rejected takeoff from the takeoff corridor might result in the helicopter hitting an obstacle. Paggi said H-V envelopes are demonstrated on only one type of surface (usually a runway) and cannot be applied to all surfaces from which a helicopter can be operated.

To guarantee actual one-engine inoperative (OEI) capability, AgustaWestland proposes that the regulation clearly require a statement of applicability, such as, “This level of performance can be achieved only over this specific surface.” Paggi also suggested that the VTOSS (takeoff safety speed) concept should replace climb-out speed.

“Safe vertical rejects and hover-out-of-ground-effect fly-away performance provide a safer and operation-oriented envelope,” compared with the existing “no-fly zone,” he added.

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Much like the military already do then:ok:

[speds]

As a big fan of training for Fly Away when such procedures are described in the RFM, I do wish that there was a Training WAT Chart for Fly Away to allow for safe a realistic use of the OEI Training Switch.

[slow n low]

Much like the military already do then:ok:

Indeed crab.. Our Airbus heli type has "height loss on eng failure" charts (commonly called "flyaway" charts) which gives us a well defined height on which to base our "flyaway" call on.... Works very well with the old "towering OGE" departures, or assessing the height to conduct a hoist/winch. It does have a whole bunch of conditions though (2 sec reaction time, pitch to 15 deg ND, Nr>97%, 40KIAS reduce pitch, ect ect.

We even have a Vtoss presented to us to consider..:ok:

I was always under the impression that us mil guys were way behind the drag curve (pardon the pun) when it comes to flying the pucker profiles to achieve the lowest risk approaches / departures. (Our assessments of "flyaway" and "committed" were very subjective but are getting less so as we get access to more performance data on our aircraft)

I find it hard to believe any of the civvy OEM's and operators would not have access to very specific performance data / criteria for approaches, departures and hovers in the OEI case. (Perhaps I am confusing this with Category A or PC1? Hopefully someone can enlighten me, happy to be educated on this!)

[Non-PC Plod]

speds - totally agree. I had to use normal height loss during flyaway charts, then started by adding 150' for the wife & kids and seeing how it went when doing OEI flyaway training. Not helpful having no graph! (I guess we are both talking AW139?

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Slow n Low - The CatA/PC1 profiles are very proscriptive and exact in the way they must be flown to stay legal and guarantee the required outcome - they are not much use when it comes to non-CatA/PC1 arrival or departure profiles but they are often all you have to go on.

Height-loss graphs won't take into account obstacles and VTOSS is often much higher than a safe-single engine in level flight speed because it is calculated to give a climb following an engine failure. With our mil-style vertical departures (non catA/PC1) you are left to cuff figures and use experience of how the aircraft is flying to assess when to transition safely.