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delta3
13th Jun 2005, 22:51
Overshooting the landing spot.

Suppose you feel you are overshooting the landing spot, perhaps because of a small tail wind, or some updraft. Which of the following options is preferred ?

1. Slow down for a steep approach
2. Make some extra turns
3. Side slip

I personally sometimes use the last, but some pilots advised against it.

What are the pro's and con's

Delta3

SASless
13th Jun 2005, 23:14
Infinite range of options....depends whether you are "over shooting" or "over arc-ing". To overshoot connotes rate of closure as an issue....over arc-ing suggests going steeper than desired but with rate of closure rate less an issue. Steep and slow ok...steep and fast ....not cool GI!

Over shooting can wind up being the more awkward of the two in my view although the other can be a bother.

Relative wind is a key issue....power availibility is always an issue....in Bell products particularly...LTE is an issue. As you near the ground...the more "normal" your aircraft attitude and power demand needs to be...sticking the tail into the ground upsets the Boss...over torquing miffs the engineers...as it takes them away from the Uckers game. Running into a tree gets the Greeners on your wagon, along with the engineers and Boss.

Going a bit steep is ok...doing "S" turns is ok...aerodynamic drag works I guess....going around and starting over never hurts. It all depends upon the situation.

Picking the exact landing spot you intend to plunk the skids/wheels down on is the key....beginning before you lower the nose or collective to initiate the approach and going for that exact spot will help prevent finding yourself in that pickle.

cl12pv2s
14th Jun 2005, 03:30
Hello,

SASless has pretty much mentioned the factors concerned, I just want to add my two cents...

Infinite range of options....

The earlier you can recognise that you are not right, the more options you have.

As you get slower and lower, the number of options you have reduce until the only 'safe' option is..

4. GO AROUND

Most situations are recoverable with early recognition and a few subtle adjustments to 'rate of closure' and 'rate of descent'.

I think need for major S turns and sideslipping suggests an approach that is so far gone that I'd consider going around rather than trying to recover. Small turns and a little drag is OK, but if it needs so much that your PAX notice, then I would probably set up the approach again. Of course, in autorotation (when go-arounds are not an option) side slipping and s-turns are the only options.

I'd be even more inclined to go around if I had misjudged the wind direction and had a tailwind (sensed by the steepening angle and a high rate of closure)....as I would be doubting the quality of my 'recon' of the LZ. If I'd stuffed up the wind direction, then what else didn't I see?...wires, obstacles, etc..etc.. Obviously there is not much you can do about a wind-shift. You just have to deal with that!

So to summarise...

The earlier you can spot that you're off the line the better. All those techniques Delta3 mentioned will work...however... Each situation is different, and the hazards vary (as in SASless's post). You don't want surprises when doing a downwind approach! Going Around is always an option, and the decision to do so, shouldn't be left too late.

cl12pv2s

Added after!:

1. Steep Approach Pro's and Con's

Con's: In the H-V curve for longer. Power requirement is higher...therefore risk of SWP and LTE higher...especially with a tailwind.

2. S-Turns Pro's and Con's

Cons: Looks messy! PAX might not like it. Also, depending on the configuration of the landing area, S-turns might not be possible due to obstacles or other aircraft / runways either side of your approach path.

3. Side Slip Pro's and Con's

Personally, I've never used this for normal approaches...only autorotations.

Cons: Feels uncomfortable for PAX, unnecessary stress on aircraft conponents, power requirements are higher and risk of LTE or SWP is higer depending on which pedal you kick in. Crabbing late on an approach (below about 50 feet) increases the risk of rollover in the event of an engine failure.

4. Go-Around

Cons: Can't see any con's to this course of action, unless fuel is a factor!

14th Jun 2005, 06:02
Steep, slow approaches are often uncomfortable and put you in the avoid curve (H-V curve) for longer; a very steep one can obscure the landing point and obstacles/wires etc.

Side slipping is a very fixed wing sort of technique but can be very effective - it tends to distort your IAS indications and can feel uncomfortable to pax. You need ETL if you are in an underpowered helo and if you sideslip to the hover and drop off ETL you will have a large power requirement at the bottom

Turns are good if you have the room.

As the others have said - if in doubt, go around and set it up properly next time.

paco
14th Jun 2005, 06:14
The unexpected steep approach can put you right in line for Vortex Ring. My preferred option would be cl12pv2s's - No 4 - Go-around.