Sunday, December 1, 2013
Helicopters as Playground Equipment
It can be assured that the life of today’s helicopter pilot will take many interesting turns over the course of operational time, and that some of the inevitable convolutions will depart from familiar aviation disciplines in wildly diverging ways. Take, for example, the case of the helicopter situated outside normal aviation environments. It has long been enjoyed, sometimes positively and sometimes very negatively, that helicopters often end up on deck and shut down in settings other than those suggesting normal aviation surroundings, and that in those sundry places they have an amazing capacity to attract wide varieties of random interest, usually innocent but sometimes either unintentionally or deliberately threatening.
I can recall more than a handful of occasions over the years that put our EMS airframes at risk as a function of peculiar location and circumstance. In addition to hospital helicopter landing facilities in crowded urban locales, which were sometimes vulnerable to intrusion by public walking traffic occasionally demonstrating a fondness for throwing rocks – or even discharging firearms – we very often found ourselves completely offsite, introducing security factors not covered in any regular aviation reference. We once had an air ambulance AStar experience a maintenance interruption to normal operations while standing by to transport an accident victim from a farmer’s field. We were able to quickly call in a backup helicopter, completing the mission effectively, but we were forced to leave the disabled aircraft shut down on private farm property for several hours, including an overnight period. It’s a good thing the crew was alert enough to leave the airframe supervised by responsible guardianship, because as soon as noise and activity levels diminished, and our helicopter was left to relative peace and quiet, a surprisingly aggressive gaggle of very curious Black Angus cattle moved in to conduct their own investigation. Livestock, as some will surely appreciate, have been known to gnaw and munch on airframe materials over the years, seen most often during the era of fabric-covered airframes, but old cattle habits die hard. Additionally, large bovines have a habit of “leaning” on stationary objects that cannot escape them, and tail rotors are certainly not exempt from such abuse. Our crew, needless to say, was kept busy all night preventing all possible gnawing and leaning.
More often, offsite helicopter landings end up inviting leaning, and other potentially damaging behaviors, by people. I remember one particular occasion which featured our prized first TwinStar having been assigned to grace the grand opening of a new medical facility. Some of us had planned to join the proceedings a little later in the morning, well after the duty crew would have positioned the aircraft on site. The pilot on duty that day boasted a terrific history of outstanding performance in settings other than those typically encountered in emergency medical air transport, but at that point a few environmental nuances common to EMS had eluded his collection of experiences. One area of unfamiliarity was the inevitable presence of actively curious children which materializes any time a helicopter makes a static display appearance in public, along with the propensity of those children to improvise recreational activities which focus methodically and relentlessly on using the unsuspecting aircraft as an upscale jungle gym. As we drove up, we were treated to a scene that featured our program’s most valuable possession swarmed by children climbing on every conceivable part of the airframe, literally swinging on radio antennas and tail rotor blades. We discovered our well intended but inadequately solicitous pilot quite some distance away, enjoying lunch and a lively conversation with bystanders. He, of course, was oblivious to the plight of his aircraft, but we were not able to let him leave this public relations date until our maintenance team had arrived to complete an inconvenient but necessarily thorough inspection many hours later, after the crowds had departed.
The fact that helicopter airframes are enormously strong in some ways and astonishingly fragile in others is well known to those involved in rotary wing operations, but always seems to be a surprise to those without inside familiarity. I love to tell interested but uninvolved people all about how helicopter designs are really the end product of long chains of masterful engineering achievements and compromises, and that they are positively no heavier than they absolutely must be, right down to the last pound of airframe weight. Rotor blades, as an example of exquisite design elegance, show little resistance to potentially destructive bending/flapping while at rest, but the centrifugally generated strength of the same blades, when turning at design operational speeds, exhibits immense physical rigidity and integrity. Playground equipment, by contrast, can be as overbuilt and heavy as necessary in order to achieve desired function and durability. So, conflation between playground equipment and helicopters should be strenuously avoided.