At an airport with both runway and helipad (KASH) I have seen both being used for helicopter takeoffs and landings. Is there anything that causes the helicopter pilot to choose to use the runway instead of the helipad?
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asked Nov 27, 2015 at 14:18
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4 Answers
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I know you asked specifically about runway versus helipad departures, but I thought I would lay out all the options available to the heli pilot, and you can see what all the choices are.
There are three different areas on an airport that a helicopter can operate from:
Non-movement area -- this is the area of the airport that is not controlled by the ground or tower controller. It often consists of aircraft parking areas or an area leased by a tenant. It is separated from a movement area by this the marking below. Helipads may be found in non-movement areas, such as the Coast Guard helipads at SFO and JFK.
Movement area -- this is the area of the airport controlled by a ground controller, and separated from the runway area by this marking:
. Helipads can be found in movement areas.Runway area -- this is the area controlled by the tower controller, and contains the runways used for landing and departing traffic.
This picture from KHWD shows the three areas:
Regardless of which area is used, almost heli departures from towered airports are coordinated directly with the tower controller because the aircraft enters the controllers airspace.
At non-towered airports, helis operate out of the flow of fixed-wing traffic, and need to self-announce like any other aircraft.
Additionally, helicopters can make three different kinds of departures:
max performance take off -- which begins with a near-vertical segment, and then transitions to a horizontal. This is typically used from a confined area, and looks something like this:
normal takeoff -- this begins in an in-ground effect hover with a horizontal segment until translation lift is assured, then transitions into a climb:
running takeoff -- when there is insufficient power to begin with an in-ground effect hover, then the helicopter may begin its departure by sliding (skids) or rolling (wheels) along the ground, until translational lift can be obtained, then transitioning into a normal takeoff:
The choice of departure area and departure type are for the most part independent, but they are obviously linked based on performance and obstacles.
The departure area is an operational decision. When the helicopter is operating from a remote part of an airport, the pilot will often make a departure from a non-movement area (helipad or ramp) so she doesn't have to taxi to the runway. If the helicopter is a passenger flight, such as air-taxi, it will most likely operate from the runway or a helipad in the movement area.
The departure type is a performance decision, based on obstacles, weather, weight, and available power. Hot & high departures might require a running take-off. Lightly loaded twin-engine copters in normal weather can safely make high-performance departures over obstacles in the desired direction of flight.
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1$\begingroup$ Spot on. This sentence is the crux of the answer -
The departure area is an operational decision$\endgroup$– SimonCommented Nov 27, 2015 at 19:28 -
1$\begingroup$ i have noticed that helis with wheels like to do running/rolling departures on runways. Also, I have seen a lot of large military helis depart in formation using rolling takeoffs from different parts of the runway, in order. $\endgroup$– rbpCommented Nov 27, 2015 at 19:32
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2$\begingroup$ Yeh. I think that's because of wear on the skids, especially from runways. If I had wheels, I guess I'd do a rolling take off every time since it's the lowest power requirement. Even on grass, the skid plates wear. But as you say, ops is the key. I worked on a line of Wessex IIs (H34 to the cousins) and the layout of the pan was such that hover take-off followed by hover taxi to a dedicated grass runway was the norm. $\endgroup$– SimonCommented Nov 27, 2015 at 19:35
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$\begingroup$ I have heard helicopter pilots being instructed to land either on the paved runway or at least sixty yards away in order to avoid blowing foreign objects and debris onto it. $\endgroup$ Commented Mar 17, 2018 at 2:10
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One reason is to avoid damaging light aircraft or other property
I had a case back in the 1980's where I had brought a Navy helicopter to an airshow for a static display. (Gross weight about 12,500 lbs). While doing an air taxi to the spot where I was to display the aircraft, the tower told me to land immediately. My rotor wash was causing some light aircraft that I didn't see clearly (downwind from us) to strain at their tie downs. We used a rolling ground taxi to get to our position. (Air show was good fun, good weather, etc).
When we departed, I coordinated with the tower to do progressive taxi to the runway, and to depart from there, because most of the aircraft from the airshow were still there, and we had to get back to our base. We wanted to reduce risk as far as possible to anyone's light aircraft (there were a lot of them) from our rotor wash.
We took off from the runway to prevent damage/disturbance to other people's property at the airport. All's well that ends well.
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My impression was that runway takeoffs are easier / safer because you remain less in the unsafe zone where auto-rotation is precluded.
e.g. See the chart below. You want to avoid the red zone, the so called "coffin corners" (not to be confused with a similarly called but totally different operating envelope for Aircraft at high speeds). So airspeed helps.
Basically auto-rotation is your safety pass in case of engine / transmission failure etc. So you want to avoid situations where you are gaining pure height without any airspeed.
See the recommended take off profile on the chart below. It increases airspeed a lot before the height increases significantly. That's what you get in a runway takeoff but I guess could also do in a helipad takeoff depending on the surrounding constraints on flight path.
answered Nov 27, 2015 at 16:11
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4$\begingroup$ There is no difference in the take-off or landing profile to a runway or a helipad. Remember helicopters do not (except in a few scenarios) roll along the runway and rotate. They lift into a hover, accelerate in ground effect, gaining translational lift until about 45 kts, then climb. Same for helipads or runways. I can avoid the red areas landing on a helipad just as easily as I can landing on a runway. $\endgroup$– SimonCommented Nov 27, 2015 at 16:29
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5$\begingroup$ @Simon Right, but if you take the recommended take off profile you need to be doing close to 100 kmph at about 10 ft above the ground. The runway is one clearly safe place you can do this. If your helipad surroundings offer the clear area to do it, that's great too. That's why I had the part to my answer which clarified that you could get the same safe flight profile from a Helipad too but obstacle clearance is a must. $\endgroup$ Commented Nov 27, 2015 at 17:10
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$\begingroup$ there are plenty of areas on an airport besides runways where normal departures can be done in the non-shaded areas of the H/V diagram, including taxiways and the grass between the runways/taxiways. I have even "landed" and "taken off" from Frazier Lake's water runway in a copter equipped with emergency pop-out floats. $\endgroup$– rbpCommented Nov 27, 2015 at 18:39
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2$\begingroup$ @simon Isn't 50 knots 92 kmph? $\endgroup$ Commented Nov 28, 2015 at 2:29
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1$\begingroup$ I've never seen a helipad in real life that has any room to do anything other than a max performance take off (or landing along roughly the same profile) but this may be because all of the helipads I have seen have been at places like hospitals... $\endgroup$– MichaelCommented Oct 8, 2018 at 18:58
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Though I'm not sure of the exact circumstances, the helicopters may be carrying out a rolling take-off. This is done in some cases where sufficient power is not available for normal (hovering) takeoff, like high gross weight etc.
In these cases, the helicopter is rolled down the runway to gain sufficient speed (to generate the required lift), so as to satisfy the power requirement. As this technique uses up considerable distance (for the takeoff roll and initial climb), and requires a smooth surface (during roll), the runway is preferred.
In case the helicopter had taken off from runway normally (i.e. in hover), the ATC might have asked the pilot to use the runway so as to let the other aircraft know which direction the helicopter is going.
answered Nov 27, 2015 at 17:19
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2$\begingroup$ you can make any kind of departure from a runway, but you can only make a hover (normal) or high-performance takeoff from a helipad $\endgroup$– rbpCommented Nov 27, 2015 at 18:29
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1$\begingroup$ I've made many "limited power" take-offs from somewhere except a runway, including sliding skids across the ground on grass (which is actually preferable since if causes less wear on the skid plates, although there is a slightly increased risk of mistakes since on grass, a skid can catch on something). $\endgroup$– SimonCommented Nov 27, 2015 at 19:51