Setting up and managing helicopter landing sites


CarolinaFireJournal - Bob Twomey
Bob Twomey
10/10/2014 -

Most local EMS services, fire departments and rescue squads have had the use of air medical helicopter transport services at their disposal for well over 20 years across most of the country. Patient transport via helicopter has become routine for many of us, and an occasional occurrence for others. However, detailed, basic training in the proper selection, use and management of landing sites, also known as landing zones (LZs), appears to still be lacking for many emergency personnel.

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Photo 1 is a typical remote LZ.

LZ management is one skills area of seemingly relative unimportance; that is, one of lesser concern, when there are only so many hours of available training time and so much to train on more directly related to our specific job(s). After all, we can leave landing the helicopter at the scene up to the pilot and aircrew, right?

That’s one way to look at it, but if you adhere to National Incident Management System (NIMS) and Incident Management System (ICS) criteria, the command agency and officials are responsible for total scene management — including air resources should they be needed. This does not mean that you do the job for them, but it does mean that you will provide for this resource on your scene. If you don’t have a working knowledge of helicopters and their physical requirements and limitations, then how are you going to properly manage and provide an LZ for them safely?


Photo 2 is a typical remote LZ landing.
 

Photo 3 is a football field landing of two helicopters.
 

Photo 4 shows establishing LZ atop Looking Glass Rock.
 

Photo 5 — maneuvering a large rock.
 

 

It is more likely that you, as rescuers, will be selecting, marking, and managing LZs on your rescue scenes more than any other component of helicopter use. As such, this article will concentrate on LZ site selection, hazards and hazard marking, verbal and non-verbal communications with aircrews, nighttime LZ operations, and professional management of the LZ.

Selecting an LZ

Sometimes, there is just no “good” LZ to be found close to your rescue scene. At a minimum, a “bad” or less desirable LZ is one of those LZs that forces a pilot to decide safety over suitability for landing, given the type helicopter he or she is flying, the weather conditions at the time (especially wind), approach and departure paths, ground slope, environmental hazards (dust, snow, debris), and physical hazards (power lines, trees, buildings, people, livestock, etc). Early into the rescue operation, should a helicopter be needed, finding a suitable, safe LZ should be high priority, even if it is some distance away from the actual rescue scene.

As rescuers, there are some basic fundamentals to keep in mind when selecting an LZ for your responding helicopter. An acronym we use in teaching helicopter classes is SSBAT (Size, Shape, Barriers, Approach and Takeoff).

In general, for most mid-size air ambulance helicopters (B0-105, BK 117, Bell 407, Bell LongRanger, EC 135, etc), an LZ should be 100 feet by 100 feet, which is about one-half acre in size. This allows for maneuverability by the pilot within the LZ, and provides enough room for the pilot to perform emergency landing procedures in the event of engine or component failure upon landing or takeoff. At the very least, 75 feet by 75 feet is the smallest LZ that should ever be used, and on a hot or windy day, an LZ this small is pushing the limits for safety.

A general rule is: the bigger the LZ, the better and safer it is. For nighttime landings, no less than 100 feet by 100 feet should even be considered. Bigger helicopters, like a Bell 412, or UH-1 Huey, should have an LZ 125 feet long by 100 feet wide. A Blackhawk would require a 200 feet long by 100 feet wide LZ for adequate safety. You can see that size is not only important for physically accommodating the helicopter and its “maneuvering room” requirements in the event of an emergency, but also for things like helicopter “rotor wash” (downward wind generated by the spinning rotors) that can damage ground equipment as well, so provide as much room as possible in your LZ selection.

Generally, a pasture makes a good LZ as long as there are no livestock present. It can be dangerous to land a helicopter around horses, cattle or other livestock. Great care must be exercised if you choose to set up your LZ in a pasture to avoid stampedes, livestock running through fences, or even into the helicopter or tail rotor. Most pilots will not land in your LZ if they see livestock present.

Shape of the LZ basically deals with usable length and width of the touchdown area relative to hazards such as trees, poles, vehicles, wires and other obstacles that can pose safety risks to the helicopter. Shape also includes the slope of the land at the LZ. Generally, the safest helicopter approach to the touchdown area is along a gentle “glide path” to the point of touch down during the final approach. Likewise, during takeoff, an LZ with enough open area in front of the helicopter as it lifts off and accelerates into forward flight is much preferred over an LZ requiring a vertical lift-off from a tight LZ. Slope of the ground is very important as well. Landing a helicopter on too steep of a slope can cause serious problems such as “dynamic rollover,” where the helicopter literally overturns once it exceeds a certain critical angle. You should find as flat an area as possible for the touchdown area, but in general, do not exceed a five percent slope — a slope that drops five feet in 100 feet. An experienced pilot can quickly tell if a slope is too steep to land safely, and he will usually move to another location.

Barriers refer to any elevated obstacle that poses a risk to an approaching or departing helicopter. Obvious barriers include trees, wires, poles and towers, fences, flagpoles, antennas, buildings, rock formations, and so forth. Tall objects close to an LZ require a pilot to adjust or sometimes deviate from safer glide approaches to the touchdown area. In hot weather, high terrain elevations and wind can cause challenges at the least and crashes at the worst. While it is true that today’s powerful helicopters can perform some unique flight maneuvers, why chance an accident, endangering the aircrew, ground personnel and the helicopter? Find a safe, level LZ free of barriers close to the touchdown area. Everybody wants to go home in one piece at the end of the day.

Photo 1 is of a typical remote LZ. While there are trees surrounding the LZ, this LZ was laid out at 80 feet by 80 feet, with approach and departure path angles clear of tall trees. This is a good LZ. Another remote LZ (photo two) is shown in the edge of a pasture. A tree line is on the right, and a fence on the left. However, the approach into the LZ was clear and wide, all the way to the touchdown point. Note also that there is not too much slope on this LZ. A football or soccer field is used to land two helicopters (photo 3). There is plenty of maneuver room, and with the exception of the goal posts and stadium lights, approach and departure paths are open and free of obstacles. This is a good LZ. Photo 4 shows an established LZ atop Looking Glass Rock in Transylvania County. It is a tight LZ, but as Photo 5 shows, we have landed an MD-500 and BO-105 in this LZ before. But there are trees surrounding the touchdown area, marked with an “H,”and approach and departure paths angles are steep, requiring plenty of reserve power and careful maneuvering.

For simplicity, I am going to combine the “A” and the “T,” as we have already been discussing them: approach and departure paths. Notice that as the helicopter approaches the intended touchdown point, the aircraft is “flared” at an angle approaching the ground. This is a normal, safe approach. Notice the angle of the helicopter just before it touches down. This maneuver is slowing the helicopter to near zero forward airspeed just before the skids touch down. This is why you need to provide the pilot a big enough LZ so he can perform this maneuver rather than a vertical descent from an elevated position.

Takeoffs, or departures along a departure path, are just the opposite. The pilot needs room to acquire forward airspeed prior to lifting out of his or her LZ, when possible. This prevents the pilot from having to rise vertically without forward airspeed, which, in hot weather and near maximum payload and high-density altitudes, can cause problems.

It is standard practice for a pilot to land and take off into the wind. Wind coming into the rotor system provides additional lift and aircraft stability. This is a very important consideration when setting up your LZ, as pilots will always try to land into the wind and take off into the wind. On a day or night without any ground-level winds, a pilot has more discretion in how he chooses to approach or depart your LZ. In windy conditions, barrier hazards will play a more prominent role in how the aircrew approaches and departs your LZ, so you should take this into consideration when communicating with the pilot about how you prefer him to approach and depart your LZ. However, you must remember that the final decision on approaches, landings and takeoffs will ALWAYSrest with the pilot in command of the helicopter.

LZ Marking and Communicationswith Aircrews

This now brings us to another very important area of interaction with helicopters: communications and marking ground hazards. In general, you should select an LZ that does not have tall grass, greater than one foot high or more. Tall grass can hide debris that can damage skids, landing lights, searchlights or antennas projecting from the bottom of the helicopter. Tall grass also reduces the ability to hover, as the grass “absorbs” the downward rotor wind, giving less effective lift for the aircraft. Hot searchlights and landing lights can ignite dry, tall grass under a helicopter. Likewise, tall grass, weeds and vines and can also become entangled in the landing skids upon lift-off. It is always safer to find an LZ with short grass, no stumps or limbs that can damage skids, or other loose debris that can be kicked up into the rotor systems or engine air intake ports.

When marking hazards such as power lines which can be very hard to see from the air, you should place a vehicle under the hazard where possible. Otherwise, clear, concise radio communications with the pilot are essential in advising him what and where the hazards are, especially at night. LZ corners can be marked with LED lights or road cones staked to the ground with a piece of re-bar with a “T” handle at the top pushed down through the open center of the cone. The low-intensity LED LZ lights are very effective, quickly deployed on any surface, and low in profile, so rotor wash does not affect them. They can be seen from the air at a substantial distance, and they afford clear boundaries of your LZ. Road flares should never be used to mark anything around an LZ. Pilots don’t like anything burning around their helicopters, and when a magnesium flare is hit with rotor wash at 60 to 100 miles per hour, they tend to burn erratically, along with combustibles around them.

Marking ground wind direction can be done simply by using brightly colored surveyor’s tape tied to a stake, antenna of a vehicle, or even being held in your hand. All the pilot wants to know is the wind direction and relative speed based on how the tape is fluttering. Remember, ground winds can be blowing from a different direction than at 500 or 100 feet above ground. During nighttime landings, radio communications are much safer, as visual signals or markers are harder to see.

Another very effective way to mark an LZ and the touchdown point at night is to place two emergency vehicles at two corners of the LZ, facing into the wind, with low-beam headlights shining out into the LZ forming an “X” pattern. The helicopter approaches the vehicles from behind and into the wind, landing on the crossed headlight pattern. With this method, make sure you face your trucks into the wind and that no lights are pointed at the helicopter. Your headlights shining behind the helicopter are not a problem; just make sure they are on low-beam setting.

 

Hand Signals

There are only a fewhand signals that you need to effectively communicate with a pilot when radio communication is not available. These hand signals are internationally understood and recognized, and can even be used at night with light sticks or light wands.

In Photo 12, the LZ manager extends his arms upward as shown to indicate to the pilot “this is your LZ, land here.” During the pilot’s reconnaissance circling above the LZ, the next signal is to show the pilot the wind direction. In Photo 13, the LZ manager brings his outstretched arms together, palms together, forming a helicopter tail boom, showing the pilot that he should approach you from the direction of your outstretched arms, which will be into the wind.

As the helicopter is on the “short final approach” to the LZ — generally one-quarter mile or less from you — you use the signal “come towards me” (as shown in Photo 14). This is signaled by holding your arms out straight and parallel to the ground, palms up, and pulling your hands towards you by bending your elbows, almost as if you were pulling the helicopter towards you.

Next, once the helicopter reaches the touchdown spot in the LZ, hold your arms outstretched from your sides and parallel to the ground as seen in Photo 15. This signals the pilot to stop and briefly hold hover position. Then, the LZ manager signals the helicopter pilot to land by bringing the arms downward from the “hold hover” position towards the ground at a 45 degree angle. (As shown in Photo 16.)

These signals work effectively and are easy to use. There is little chance of miscommunication if they are signaled properly and practiced to the point they come naturally to you. Use of helicopters in rescue is becoming more common today, and you should learn how to manage your LZ effectively and safely. If you take on the task of LZ manager, then manage the LZ. Keep people, animals, equipment and debris out of the way of the approaching helicopter. Secure the LZ so that no one walks into the LZ area unexpectedly, or worse, walks into the spinning tail rotor because it can’t be seen due to spinning so fast. Let that pilot know you are in control of the LZ and that you will keep it safe for his aircraft and crew.

Never get complacent around an LZ or a helicopter. Take pride in managing your LZs such that no one gets hurt. An aircrew can tell in a matter of seconds whether you know what you are doing or not, so do it right. And please remember this: a pumper standing by at idle, with no charged and manned line off the reel, is useless, because when something goes wrong on a helicopter landing, it goes wrong VERY QUICKLY — quicker than you can react.

Bob Twomey is the current chief and founder of the North Carolina High Level Extraction Rescue Team, Inc., a volunteer helicopter search and rescue support team based in Transylvania County, N.C. He is the senior helicopter pilot for Wolf Tree Aviation, LLC operating out of Transylvania Community Airport. He also serves as Deputy Chief for Training in Brevard Rescue Squad. He has been active in SAR for 37 years. Twomey can be reached at 828-884-7174 or [email protected].

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Issue 33.4 | Spring 2019

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