What is the function of a backwards takeoff profile?

[MurderedOutTaco]

I'm a student commercial pilot, sorry if this is a dumb question: I have watched a number of HEMS videos on youtube in which the pilot makes a backwards takeoff from the pick up point. I assume there is some function for this, other than to impress observers on the ground? Why not 180 at hover height and then takeoff with a max P forward profile? In most of the videos I have seen there is plenty of room for maneuvering at hover height (i.e., football field, etc). Also, I assume this is only done in multiengine aircraft?

[Gomer Pylot]

The function is to allow landing back to the takeoff point in the event of an engine failure. It's in the RFM, and it's a valid takeoff profile. You don't want to have to drop straight down, to a point you usually can't even see from a larger twin, so you keep the takeoff point in sight, allowing a forward descent which requires less power to stop at the bottom. Read up on Category A operations.

[Wally]

As Gomer Pylot said. And here's a graphic:

 

http://forums.x-plane.org/?showtopic=48605

[cburg]

Got it...but what is the best way to turn...right or left?

[MurderedOutTaco]

Thanks Gomer and Wally for the explanation and for the Cat A/OEI graphic. Makes complete sense to me now. So much to learn...

[aeroscout]

You have to be careful backing up in calm winds, and even more careful with a tailwind.

If you have never experienced ETL backwards you may be in for a very unpleasant surprise.

[Gomer Pylot]

Taking off with a tailwind is almost never a good idea. The Cat A profile assumes a headwind.

 

If there is a need to turn after takeoff, it's the same as any other, turn whichever way you need to. But you don't usually want to turn until you have adequate altitude and airspeed.

Edited July 24, 2014 by Gomer Pylot

[WolftalonID]

One way we practiced tail control was hovering down the taxiway doing pirouettes. This was done both to the right and to the left. It was required to maintain center line, hover height, and rotation speed kept constant without whipping the tail about when the wind caught it. Really works the pedal control especially when there is a breeze. I loved doing them by the time I was in commercial training. At first they were so dang hard, in my private level hovering still was a challenge!!

 

This drill however brought a deeper tail control skill for doing difficult departures like this as well. So dont sweat the wind, learn it, work it, respect it, keep it on the nose if you can.

[cburg]

So what do we think about this (not the safety aspect, which is obvious, but the technical aspect).

 

https://www.youtube.com/watch?v=1HCFIuwy1m4

 

http://www.youtube.com/watch?v=YKEMgj45Duo#t=16

 

I guess he missed the class on "never dive"

[WolftalonID]

Well it isnt a 22. Cant say its ok because I dont know what that heli is supposed to be able to do...but that video deffinatly shows what it can do!

[Matt321]

I'm always willing to learn a new technique but after doing medevac in a single engine helo for years and never hearing this I'm a bit skeptical. If the visibility in this large twin is so bad looking out the chin bubble, how is it looking backward? I'd rather lose an engine and descend vertically for a hard landing than clip my tail rotor and spin like a top. Maybe I'm misunderstanding your technique.

[Gomer Pylot]

It's a standard, published technique, not mine nor anyone else's here. It's not a function of visibility, but of the ability to land OEI back at the point of takeoff. If all you've flown is single-engine, then you've never needed to learn this technique, although it could be used by a single-engine helicopter. Depends on what is beyond the takeoff area and how optimistic you are.

[eagle5]

I used to have to back into my parking spot from the taxiway all the time in the 22. So what model twin are we talking about here?

[Gomer Pylot]

Any transport category aircraft. Anything that can do Cat A operations.

[Matt321]

Ok, I looked at all this cool cat a stuff and at least understand the concept now. I still think we have a lot more accidents caused by collisions with other stuff then engine failures and except in the case of over water or rooftop pad you should have plenty of references for a vertical takeoff. But with less than 100 hrs multi engine I guess I'm not exactly qualified to judge. I'll just keep looking where I'm going for now.

[Pohi]

I would hope you would always know what's behind you when backing up no matter how many engines you have. Knowledge gained from just having landed at the spot, clearing turn, a walk around prior to getting in the aircraft, or any other means.

[Wally]

That profile is a single tool in your pilot bag o'tools. It's not the 'Golden hammer' that turns every challenge into a nail.

[Spike]

IMO, having the ability to see your touchdown point by moving forward is always beneficial. In certain circumstances, backing out places the machine in a better position to immediately return to your spot then simply going vertical. Plus, unless you are Verf flying, descending vertically from 100 feet or so is rarely actually “vertical”, especially in an emergency……

[AS350 pilot]

Okay, I just watched those videos. I'm going to make a quick point about them and not about the departure profile.

 

Be ware of the "look at me" syndrome of some helicopter pilots. Showing off and flying like they were in both of those videos is asking for trouble. Always fly in control, there is no need to show off. Any other legitimate commercial pilots out there will be more impressed by precise well though out flying then showing off and doing unnecessary maneuvers.

 

Fly Safe, everyone!

[Rupert]

First, the EMS takeoff:

 

1. vertical takeoff to 150' or 100' above obstacles, whichever comes first;

2. transition forward, maintain heading, and do not turn on course until 300' agl day or 500' agl night.

 

That said, anytime a pilot has a known clear space behind him, it better serves safety to keep the departure landing zone in sight, in front of the aircraft, until attaining a safe obstruction clearance altitude. From outside the aircraft, this may look like a backwards takeoff.

Very conservative. Very safe.

This backwards takeoff upsets some flight nurses, so do the less-safe vertical or forward takeoff when necessary in order to placate the nurse.

 

Backwards = Safety

 

Backwards does not equate to showing off, but, rather, to doing it the conservative, conscientious way, single or dual engine.

 

Backwards takeoffs benefit single engine operations just as much as they do dual engine operations.

 

If you lose your only engine, you will find it much easier to descend and hit your original lz if you can see it in front of you, like, just in front of your feet.

 

I have three pilot friends who have lost their single engine while at a 100' hover. Two of them walked away from very damaged aircraft, and one stayed three weeks in Intensive Care. One of the walk-aways hit about 20 feet in front of his position over the ground when he lost the engine; the other walk-away did a right-turning spiraling dive to a spot directly underneath him (a master pilot); and the third, who did not walk away, came straight down and hit hard.

 

If you lack room in front of you that will let you see your impact site, and allow you to go forward with some horizontal movement prior to impact, then back up as you take off and create that horizontal space in front of you.

[eagle5]

So I went ahead and gave this backwards takeoff thing a try. Kind of cool, but it felt rather awkward doing it. Sort of like when I practice steep approaches. If there's an obstacle to go over then the maneuver seems natural, if however I'm just doing it to a wide open ramp or taxiway then my brain keeps asking me, why are you doing it this way?

[cburg]

How about the 180 turn...power pedal on non-power pedal...heavy, hot, high?

 

Seems like non-power pedal.

[brian74]

How about the 180 turn...power pedal on non-power pedal...heavy, hot, high?

 

Seems like non-power pedal.

I can't see any reason anyone would want to do a pedal turn, unless it was only slight enough to avoid potential obstacles in the take-off path while remaining predominantly into the wind. I think the whole point is to remain aligned with the point of intended landing and into the wind in case of engine failure with high DA and/or weight. Once enough altitude is gained from the reverse takeoff, a slight decent can be used with fwd cyclic to trade altitude for bucket airspeed and achieve ETL and Vy using less power. Wind is certainly your friend in this case.

[Gomer Pylot]

The Cat A profile assumes a takeoff into the wind. Doing a pedal turn to downwind, and away from the pad, would not be the prudent thing to do.

[cburg]

I was envisioning a take-off in a confined space, like facing a tall building/object where you headed into it for landing, where you have to rotate to clear.

 

It occurs to me that it depends on HP loss on a power-pedal tune versus maximum visibility (right or left seat pilot). I fly in the center (and have no intention of getting boxed in like the example), but know some guys fly in and out of some really tight spots.

 

Interestingly, I notice when flying (as a passenger) out to oil rigs that helicopter companies seem to use slightly different TO and LND profiles...not sure why. Can't ask…we are told “don’t talk to the pilots”. Like when Neil Armstrong was on our company's Board of Directors. Best way to get fired was to go up to Neil and try to talk to him. He would not have minded I'm sure...but it was forbidden by the company.

 

They are all twins…some on tires and some on skids. Some stay vertical for 100-150 ft up and down, some do more of standard type TOLs.