This Month in Aerospace Medicine History
May 2008
by Walter Dalitsch III, M.D., M.P.H.
Seventy-Five Years Ago
The future of aviation in National Defense (National Commander, The American Legion): “To one who has spent most of the last seven
months traveling back and forth over the length and breadth of this great Country of ours, it is a distinct pleasure to be permitted to sit in
the company of the nation’s aviation élite, and to be invited to make a few remarks, brief as they must be, is indeed an honor. I say this
because in my travels as National Commander I have come to realize fully how important, how much of an absolute necessity, aerial transportation
has become to this fast-moving age. For myself, I can honestly say that I could not have gotten along without it, and I am not what you might
call altogether one of the younger generation…
“Last night I spoke in New York. Tonight I have the privilege of saying a few words to you [in Indianapolis]. Only
a few short years ago it would have been unthinkable, the mere suggestion would have been laughed down as crazy. Yet, in so brief a time, how
small has become the distance between these two great cities. After a restful night’s sleep, a leisurely breakfast, I step into my airship in
New York and on its broad wings I am whisked, safely and comfortably, to your meeting here in Indianapolis in the space of a few hours. A miracle
that in our hurrying age has become the commonplace.
“It was only twenty-eight years ago, that the first sustained airplane flight was made – here in America and by an
American. The world was thrilled but it took the supercharged demands of World War activities to bring aviation to the place it holds today—that,
probably, of the principal mode of transportation and travel of the future. The strides your leaders made after the signing of the Armistice
probably are unrivaled by any industry in the history of the World…
“How the world has shrunk in the 400 years since Magellan set sail with his little fleet to make the first circumnavigation
of the world. One ship and a handful of mariners made the circuit in three years. All of the other ships and sailors, including the leader
himself, were lost at sea or died. Yet, two fearless young men in our day circle our worldly sphere in a little over eight days, without mishap
and without serious discomfort, though I would not say that they were without dangers.
“And the end is not yet in sight. Our generation may have laid the foundation for the great sky armadas of the future
but the ships that seem comfortable and safe enough to us today will look puny and dangerous alongside the airliners of tomorrow. In a conversation
with a distinguished aviation officer of one of our services in Washington recently, I asked what the immediate future was likely to witness
in the advance of aviation. He replied that experienced aviators were loath to make predictions lest their conservative beliefs should be considered
wild dreams…
“The late President Coolidge once said: ‘Our National Defense must be supplemented, if not dominated, by aviation’” (3).
Fifty Years Ago
Open-water helicopter rescue of survivors (U.S. Naval Air Facility, Elizabeth City, NC): “The unparalleled expansion of the
use of rotary wing type aircraft in the military services, and most recently in civil aviation, has fired the imagination of the air minded
public. The helicopter has become the modern day magic carpet which can hover at human command and from which seemingly all tasks can be accomplished
at the operator’s whim. This enthusiasm is the life blood supporting the technical progress in rotary wing engineering and is vital to its
growth. However, this same widespread interest among the non-technical, although aviation-conscious, general population has had an inevitable
effect which has become a matter of increasing concern to those thoroughly familiar with the limitations of the helicopter. This is the general
over-optimism among the nontechnical public as to the capabilities of this aircraft. Unwarranted expectations concerning the ability of the helicopter
to accomplish dramatic rescue of people in distress is encountered with increasing frequency. This constitutes a handicap occasionally for
those responsible for the design and operation of the helicopter who, all too often, are dependent upon the intelligent and understanding
support of the public to utilize effectively this type aircraft.
“One of the many proven uses for the helicopter—rescue from relatively inaccessible places—has become so
comprehensive it is now a specialty in flight operation made unique by the aircraft itself. It is not the intent of this report to define that
major role in even general terms but rather to present a detailed study of a single but highly important aspect of rescue work, specifically:
The problem of helicopter recovery of survivors in the water, particularly in open seas. This aspect of rescue work imposed on the helicopter
has become a matter of primary concern to the aviation-oriented medical officer because of excessive dangers involved with an associated mortality
causally related to the rescue procedure itself. In this area widespread misinformation exists, some of it dangerous to the survivor himself if he
is misinformed…
“The increasing use of the helicopter as a rescue aircraft is accompanied by a public overestimation of its capabilities
for such work. Attempted rescue of survivors from the water by helicopter is a specialized and hazardous operation influenced by environmental
conditions, techniques and effectiveness of aircraft plus accessory equipment, and the physiologic stamina of the survivor. Rescue failures
are sometimes disastrous to both survivor and rescuer…” (2).
Twenty-Five Years Ago
Current Naval Aviation mishap rates (U.S. Naval Safety Center, Naval Air Station, Norfolk, VA): “Approximately 50% of all
class A flight/flight-related naval aviation mishaps (involves intent for flight with destroyed aircraft, fatalities, permanent total disabilities,
or at least $500,000 of property damage and injury costs) continue to involve pilot error as a contributing factor as determined by the mishap
boards, endorsers in the chain of command, and the Naval Safety Center. These pilot factor mishap rates, i.e., number of mishaps per 100,000
flight hours, during the calendar year 1977-1981 time period for attack, fighter, and helicopter aircraft (excluding trainers) were 3.90, 7.14,
and 3.09, respectively.
“It is imperative, therefore, that all personnel involved in aviation safety, either directly or indirectly, including
those involved in the budgetary processes, development of training criteria, commanding officers, and pilots, be provided the factors associated
with the unsuccessful accomplishment of the aviation missions.
“Research and theory indicate that mishap rates tend to decrease as experience increases. This is well illustrated in attack
aircraft. The pilot factor mishap rate significantly (a=0.53) decreased as time in model increased. The rates were particularly high for pilots
with less than 100 h in model and also for pilots having 1000-1500 total hours who had less than 500 h in model (e.g., transition pilots).
Uncontrolled flight and mishaps during offensive maneuvers were major problem areas for these aviators… Recent flight experience, as measured
by hours in the past 30 d, showed little statistical relationship with mishap rate (α = 0.555) though pilots flying less than 10 h in 30 d possessed
the highest rate, particularly if lifetime hours in model were less than 300. Violation of regulations was the top error for this group…
“Fighter aircraft mishap rates do not appear to conform to the hypothesis of decreasing rates with increasing experience.
Though the pilot factor mishap rate in fighter aircraft was highest for aviators with less than 300 h in model (uncontrolled flight and poor
landing techniques being major problems), particularly if total hours were between 1000 and 1500—the transition pilots—the result
was not statistically significant (α = 0.364). Moreover, the rates tended to decrease as experience increased to 500 h in model but the
rates then increased with further experience… The reasons for this increase appear to be partially related to increased judgment error rates.
Flight hours in 30 d were significantly (α = 0.001) associated with mishap rate. Aviators who accumulated 20-30 h in 30-d periods had
the highest rate, particularly if lifetime hours in model were less than 300. Failure to maintain flying speed and poor landing techniques
were the top contributors to the mishaps in this group… A high rate of judgment errors in this group—which did not exist in attack
aircraft—was a factor in causing this peak.
“Pilot factor mishap rate in the helicopter community significantly (α = 0.083) increased as lifetime hours in
model increased. Pilots with over 1000 h, in fact, possessed the highest rate. Inadequate flight preparation was the top pilot causal factor
for this group… Furthermore, the mishap rate was significantly (α = 0.0001) related to hours in 30 d. Aviators who flew more than
40 h had the highest rate, particularly if lifetime hours in model were greater than 1000. Again, inadequate flight preparation was the top
contributor… These ‘trends’ contrast sharply with the ‘expected’ decreases associated with increased experience.
High mishap rates associated with failure to maintain flying speed, misjudgment of distance, altitude or position, violation of regulations,
inadequate flight preparation, and physical/mental condition of pilot (stress, fatigue, vertigo, etc.) for the pilots with the greater
experience—lifetime or 30 d—were factors in these ‘trend reversals’” (1).
References
- Borowsky MS, Wall R. Flight experience and Naval aircraft mishaps. Aviat Space Environ Med, 1983; 54(5):440-6.
- Ireland RG. A new device for helicopter rescue of survivors afloat. J Aviat Med, 1958; 29(5):358-65.
- Johnson L. Aviation for national defense. J Aviat Med, 1933; 4(2):62-7.
