At AirVenture a couple years ago, a group of air show performers were discussing an often-overlooked topic. That topic was “margins.” Subsequently, more room has been devoted to issues related to margins in Ops Bull and other ICAS publications, but it is the type of issue that needs to be continuously explored from multiple perspectives.
So, what are margins and why are they relevant to the air show industry? Simply put, margins in the air show environment refer to the buffer area that performers give themselves to safely recover from a maneuver.
Hypothetically and as one example, a performer has practiced a torque roll enough times to insure that the maximum altitude lost while sliding backwards is 400 feet, that the maximum altitude required to reestablish control is 400 feet and that the pullout takes a maximum of 600 feet. The performer will then set a minimum altitude for the torque roll at 1,800 feet, giving a 400 foot margin beyond what he knows he needs in the event of an unforeseen complication in the maneuver (400 foot slide + 400 feet to reestablish control + 600 feet to pull out + 400 foot margin = 1,800 feet). Using this same example, a performer who set a minimum altitude for the torque roll of 1,400 feet would effectively be giving himself/herself no margin at all.
Obviously, margins are unique to each aircraft and can differ not just from aircraft to aircraft, but from maneuver to maneuver for a particular pilot. They can even vary based on a variety of weather conditions for the same pilot in the same airplane.
Allotted margins are important to identify because they require a second-level knowledge of the maneuvers being performed. Not only must performers know how to correctly execute their maneuvers, but they must also be familiar with any possible deterioration to which the maneuver may be susceptible. This intimate familiarity with each maneuver is only gained through repetition and practice. So, in addition to the additional buffer/cushion offered by the margin itself, the performer benefits by becoming sufficiently familiar enough with the mechanics and dynamics of each maneuver to set the margin in the first place.
Flying without properly identifying your margins can be compared to driving down the interstate without wearing a seatbelt or performing trapeze acrobatics without a net. Under perfect circumstances, there would never be a problem. But, when flying in an environment with as many variables as the air show aerobatic box, operating without set margins is simply a bad idea.
Have you identified the margins for each maneuver in your performance sequence?