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Posted

OK. I've got just about all of the flight tasks down so that I can take my private checkride next week. One of the only areas I still have a problem with is orbiting around an off-airport landing spot (pinnacle or confined area) at a constant altitude and airspeed.

 

Our training area has ocean on one side and steeply rising terrain on the other side. The rising terrain makes it impossible to use the compass or the rotor tip plane distance above the horizon as a reference. As a result, I end up climbing and descending as the hill looms up in front of me and then disappears as I turn away. There is usually a good breeze blowing either onshore or downslope just to add a little variability to the mix. Do any of you more experienced pilots have words of advice on how to keep it level when the horizon changes rapidly?

 

Also, I've heard from different instructors at the same school, that:

1.) Airspeed should remain constant during the orbit (as I was taught during fixed wing training), or

2.) The airspeed can be allowed to vary around the orbit to help determine wind direction (with a noticable increase as you turn into the wind).

I know GPS ground speed compared to airspeed will tell me instantly, but I'd like to be able to do it without that aid.

What are other instructors teaching in this regard?

 

Thanks,

WW

Posted
OK. I've got just about all of the flight tasks down so that I can take my private checkride next week. One of the only areas I still have a problem with is orbiting around an off-airport landing spot (pinnacle or confined area) at a constant altitude and airspeed.

 

Our training area has ocean on one side and steeply rising terrain on the other side. The rising terrain makes it impossible to use the compass or the rotor tip plane distance above the horizon as a reference. As a result, I end up climbing and descending as the hill looms up in front of me and then disappears as I turn away. There is usually a good breeze blowing either onshore or downslope just to add a little variability to the mix. Do any of you more experienced pilots have words of advice on how to keep it level when the horizon changes rapidly?

 

Also, I've heard from different instructors at the same school, that:

1.) Airspeed should remain constant during the orbit (as I was taught during fixed wing training), or

2.) The airspeed can be allowed to vary around the orbit to help determine wind direction (with a noticable increase as you turn into the wind).

I know GPS ground speed compared to airspeed will tell me instantly, but I'd like to be able to do it without that aid.

What are other instructors teaching in this regard?

 

Thanks,

WW

 

If you keep the helicopter in trim there should be no difference in airspeed as you roll in and out of turns, regardless of the wind direction or windspeed. There will be a difference in groundspeed which may or may not be as noticeable as you'd like, depending on how strong the winds are. I would recommend you keep a nice constant airspeed and attempt to pay attention to your apparent groundspeed and ground track and try to figure the winds that way. If you have GPS available use that like you said. Also, you should always be attempting to ascertain the direction of the winds, not only when doing pinnacle or confined operations. If you can figure out the winds enroute that should help you figure it out when you get there.

 

I've heard this thing about airspeed changing as you turn into the wind. That's not true unless you're dealing with some kind of windshear where you get a rapid acceleration of wind all at once. Windspeed is measured relative to the ground. Once you leave the ground there is no wind. You are a passenger now in the airmass that, on the surface, is interpreted as wind. Anyway, that's another topic, hope it helps!

Posted

Keep the attitude, and thus the airspeed, constant. Keep an eye on the attitude indicator and the VSI, if you have one. Actually, the airspeed will need to be slightly slower in the turn to maintain altitude, assuming constant power. It takes more power to maintain an airspeed in a bank, so in a 15 or 20 degree bank, you will need to be a few knots slower to keep a constant altitude. A VSI is a very good way of keeping things stable, along with the attitude indicator keeping a constant attitude. With practice, you'll learn to read these instruments at a glance, and spot trends starting before you let things get out of tolerance.

Posted

Monitor your altimeter and/or VSI (with a nod to Gomer). Attitude is airspeed and power is altitude. If you hit an updraft and begin climbing, reduce power and maintain attitude, when you exit the updraft, resume power while maintaining your attitude. Similar for when you enter a downdraft, increase power and maintain attitude, and when you exit, reduce power and continue to maintain your attitude for airspeed.

 

As for orbiting near the rising terrain, be aware of the visual illusions of an aerial perspective, something we refer to in the U.S. Army as an "altered plane of reference", which will tend to make you want to climb or descend as you approach and turn away from terrain instead of maintaining an altitude that is known to be safe from obstacles.

 

Finally, for a visual technique, determine a point on the door, doorframe or window to measure the change in a point of reference within the confined area/pinnacle, and then plan points to fly over that are equidistant from this reference. If the point changes its location in your view, say it is lower in your field of view, then you have either climbed or moved inward of your orbit (or both). If it is higher in your field of view, you have moved further out and/or descended in altitude.

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