inverted flatspin
6th Dec 2000, 06:29
here is a very interesting article for anyone who is interested
The Case Against Tougher Medical Standards
Chasing Medical Factors is an Inefficient Means of Improving Air Safety
By Ian Blair Fries, M.D.
On March 21, 1983, a 53-year-old businessman was on an IFR flight from Fort Worth, Texas, to Champaign, Illinois, in a Piper Saratoga. He was descending over Rochester, Illinois, when he reported to Kansas City ARTCC that he was having severe chest pains and shortness of breath. He said he was hand-flying the aircraft. Conditions were marginal VFR with a broken layer at 1,300 feet and four miles visibility in fog and snow. Radar contact was lost. Witnesses saw the aircraft spin out of the clouds, with separate pieces falling to the ground after the main portion had descended.
An autopsy revealed the cause of death was atherosclerotic coronary artery disease. The pilot had been previously hospitalized in October 1982 for chest pains. He had extensive testing for possible coronary problems, but no evidence of heart disease was uncovered except for mild hypertension. He had a valid medical certificate, a private pilot certificate, and an instrument rating.
The specter of such in-flight incapacitation or impairment is the rationale for medical regulations and aviation medical examinations. Such an accident also highlights limitations of medical science in predicting accidents.
As noted below, the number of aircraft accidents resulting from medical incapacitation is small. Nonetheless, the FAA apparently sees the need to toughen medical standards for pilots. The agency has published a notice of proposed rulemaking that outlines more stringent medical criteria for many pilots, a position opposed by AOPA (see "AOPA Action," January Pilot, and "President's Position," December 1994 Pilot). As an aviation medical examiner, pilot, aircraft owner, and chairman of the AOPA Medical Advisory Panel, I assisted the association in preparing its comments to the docket. The results of my research clearly show that the high costs of stricter medical standards are not worth the small and perhaps unmeasurable increase in safety.
Preventing Medically Related Accidents
How frequently are medical conditions factors in aviation accidents? What are the most frequent medical factors? If medical regulations and examination procedures are changed, will accidents and fatalities be lessened?
The AOPA Air Safety Foundation's Emil Buehler data base provided answers to most of these questions. In the 10-year period from 1982 to 1991, there were 19,925 general aviation accidents. "General aviation" is defined as aircraft of less than 12,500 pounds not flown in scheduled service. Of these, the NTSB determined that medical factors contributed to only 379 accidents--or about 1.9 percent, fewer than 38 per year.
Since more than 98 percent of accidents have no medical factor, the majority of resources to reduce accidents should be directed toward the more common factors. It is generally accepted that more than 50 percent of accidents are caused by "pilot error," and weather is a factor in more than 25 percent. This strongly suggests that the current extensive medical regulations and 6,000 aviation medical examiners are either doing their job very well or are superfluous.
Assume that, despite the few medically related accidents, we wish to decrease that number by tighter medical standards and more comprehensive examinations. How could we do this?
Alcohol
Of the 379 accidents with medical factors, well over two thirds were due to alcohol and/or drugs. (Alcohol predominates six-to-one over drugs.) Unfortunately, there is no way that an examiner can prevent a perfectly healthy pilot from leaving his office with a fresh medical certificate in pocket, stopping at a bar, and then piloting his airplane while soused. In 10 years, 259 general aviation pilots did something just as foolish.
A 49-year-old supervisor called one of his employees to pick him up at the site of an automobile accident. The employee noted that his boss was drinking at the scene of his (first) accident. The boss then insisted upon being driven to the airport, and when they arrived, he insisted that they both go for a flight. The employee wisely declined the invitation to fly, but he was unable to prevent his boss from taking off solo in his Beech Bonanza. The flight lasted only two or three minutes until the aircraft struck electrical transmission lines while maneuvering. Toxicology of the dead pilot revealed a blood alcohol level of .325 percent, which is at least three times the level considered "drunk" by most authorities.
Another case: Earlier in the day of an accident which occurred in Leesville, Louisiana, the four occupants of an aircraft had been reported to the local sheriff's department as being drunk in a lounge. Despite their inebriated state, they successfully flew a Cessna 172 to De Ridder, Louisiana. After landing, the aircraft ran off the asphalt, bending both propeller blades. The resourceful occupants straightened the blades with a pipe wrench and then decided to celebrate at a nearby nightclub. All would have had a happy ending if they had not returned to the airport several hours later that dark evening. Though further burdened with alcohol, they attempted a second flight. It ended shortly after takeoff when the aircraft impacted trees in a near vertical attitude. The 47-year-old pilot and two of his three companions were killed; the other passenger survived with serious injuries.
And then there's the pilot who landed at Pueblo, Colorado, and asked the FBO attendant if any liquor stores were open. During the taxi ride back to the airport, he consumed about half a pint of a bottle's clear liquid contents. He then carried a brown paper bag with him to his aircraft. After starting the engine, he expedited his flight by attempting takeoff from the taxiway that connected the general aviation ramp with the intersection of runways 8L and 35. The Piper Comanche never became airborne. It ran off the end of the taxiway into rough terrain, and the pilot was seriously injured.
Accidents involving alcohol are often deadly. While there is no excuse for the fact that 1 percent of general aviation accidents involve alcohol, the rate compares very favorably to that for automobiles and boats--where more than 50 percent involve alcohol. Should Draconian measures be applied to all pilots because a few inexcusably think alcohol is acceptable in the cockpit?
Other medical Factors
Subtracting alcohol and drug-related accidents leaves 171 medically related accidents over 10 years. But 69 of the pilots involved did not have a medical certificate or had a certificate that was clearly invalid. Of these outlaws, more than two thirds were imbibing. If a pilot never bothers to obtain a medical certificate, no change in medical standards or increased thoroughness of an AME's examination will save his or her skin.
This leaves a target of 102 accidents involving medical factors that might have been identified during medical certification.
Eight accidents were caused by hypoxia; these pilots flew too high without oxygen or failed to use their oxygen equipment properly. Seven pilots succumbed to carbon monoxide poisoning because of leaky exhaust systems. The prevention of such accidents is obvious.
Seven pilots had visual impairment. This variegated group included a pilot who was advised by his family doctor to use an eye patch and see an ophthalmologist. He decided to test his vision in flight before seeing the eye doctor. One pilot was blinded by a bright dome light that could not be turned off. Another complained that he had to tilt his head back to read the altimeter with his bifocals.
And still another pilot knew he had visual disturbance at twilight but nevertheless attempted a flight in such conditions. His landing was also complicated by the front quarter of a freshly killed reindeer that somehow became wedged into the rear flight controls of his Pitts biplane, jamming the elevator. This was his third accident in that unlucky year, but he had not reported the previous two to the authorities in Alaska. It is unlikely that an aviation medical examiner could have prevented these accidents.
Over 10 years, seven pilots came to grief because of flu, colds, pneumonia, and nausea, and four more to motion sickness and vertigo. Three suffered strokes--possibly the only accidents that might be related to hypertension. Two were found after their accidents to have gunshot wounds. One pilot each had hypoglycemia, aortic dissection, a sutured laceration that ripped open, acute emphysema, pulmonary embolism, or hyperventilation. One pilot had a leg cramp while landing his Luscombe in a crosswind; he inadvertently stomped on the passenger side left rudder pedal instead of his own right pedal, resulting in a ground loop. It is unreasonable to exert effort to minimize factors that occur only a few times in 10 years.
Heart Disease
The only reasonable target for medical accident prevention is the 41 myocardial infarctions (heart attacks) that occurred in this time frame. Can we predict and prevent them from occurring in the cockpit?
About 336,000 general aviation (Class II and III) medical examinations are performed by AMEs each year. The FAA is proposing electrocardiograms (for Class II after age 35) and cholesterol screening (for Class I after age 50). Would it be worthwhile to add these two tests to *every* medical examination over age 40? As half the pilots are older than 40, this would entail some 168,000 augmented examinations each year for general aviation.
To do this, AMEs would need to purchase special equipment to transmit the electrocardiograms to Oklahoma City. Blood samples drawn would have to be sent to a clinical laboratory, with the results returned to the AME, pilot, and FAA. Assume an additional cost of $100 per examination for these two tests. Under this arrangement, more than $16.8 million will be spent annually to prevent some small portion of the four heart attacks that occur while flying each year. Is that the way we want to spend our resources?
Our ability to predict heart attacks in healthy people is poor, even using very sophisticated testing. A heart attack is often the first manifestation of cardiac disease. The pilot mentioned at the beginning of this article, who succumbed to a heart attack over Illinois, had undergone extensive cardiac testing five months prior to the accident. The tests did not identify the cause of his subsequent death.
We know some factors that increase risk: cigarette smoking, obesity, and lack of exercise. The effect of elevated blood cholesterol is not fully understood, though it may also be a factor in cardiac disease-- but no one has claimed it is a predictor of incapacitation. Clear benefits from lowering blood cholesterol seem to apply only to men who already have had a heart attack.
The electrocardiogram is a beguiling test and the mainstay of cardiac evaluation. However, it is a poor predictor of future cardiac problems in an otherwise asymptomatic individual. There are no other screening tests predictive of incapacitation that are generally accepted by the medical community as effective.
But assuming that, during an aviation examination, an AME could identify a pilot who was likely to have a heart attack within the next year, the chance that it would affect flight is slim. The average general aviation pilot flies 50 hours a year. As there are 8,760 hours in a year, there is less than a 0.6 percent chance--or one chance in 175--that incapacitation will occur while flying...and a much smaller chance that it will occur during a critical phase of flight. Remember that heart attacks were only one *factor* in the four accidents each year.
Is there need for new Medical FARs?
Many accidents had several factors, and the accident might have occurred even if the pilot did not have a medical event. A 61-year-old pilot decided to ferry an Aero Commander 680 twin from Bayport to Islip on Long Island, New York. The aircraft had not flown in 14 years. Appropriate maintenance, service bulletin compliance, and required lubrication had not been done. An engine failed, the pilot failed to maintain VMC, and both occupants were killed in the ensuing crash. The NTSB also listed "incapacitation" as one of the probable causes.
As an AME, I'd like to believe that a more probing examination and stiffer medical standards would improve the safety of flight. Unfortunately, that is not the case. I'd like to believe that more resources devoted to aviation medical certification will save lives. A few lives may be spared, but chasing medical factors is a most uneconomical method to procure safety aloft.
*Those wishing to comment on the proposed changes may write to the FAA, Docket No. 27940, Notice #94-31, 800 Independence Avenue SW, Washington, D.C. 20591. The comment period closes February 21. Comments should be submitted in triplicate.*
Ian Blair Fries, AOPA 551497, is an orthopedic surgeon with extensive medical and aviation-related credentials. He is an instrument-rated commercial pilot, senior aviation medical examiner, accident prevention counselor, and chairman of AOPA's Medical Advisory Committee. Fries is also a member of the Flying Physicians Association, Civil Aviation Medical Association, and Aerospace Medical Association.
Highlights of AOPA's opposition to the more onerous of the FAA's proposed changes to medical standards:
Specifications for "personality disorders, neurosis, and other mental conditions" remain far too general under the proposed revision.
Reducing blood pressure maximums from the current 170/100 (recumbent) to 155/95 (seated) would force many with borderline hypertension to undertake expensive drug therapies and cardiovascular workups to qualify for a medical certificate.
Applicants for second-class medicals, including most of the nation's flight instructors, would be required to undergo electrocardiograms every two years. Currently, that standard exists only for airmen holding first-class medical certificates.
The FAA's former standard relating to "convulsive disorder" would change to make a single seizure event disqualifying or subject to a special-issuance medical.
The NPRM does not recognize modern medical technology in cardiological areas such as heart valve replacement and pacemakers.
Requirements would force third-class medical certificate holders over 70years of age to submit to an exam every year.
AOPA supports some parts of the NPRM, such as changes to visual acuity and color vision standards, the administration of hearing tests, and the possible certification of diabetics whose conditions are under good control with insulin or oral medication.
[This message has been edited by inverted flatspin (edited 06 December 2000).]
The Case Against Tougher Medical Standards
Chasing Medical Factors is an Inefficient Means of Improving Air Safety
By Ian Blair Fries, M.D.
On March 21, 1983, a 53-year-old businessman was on an IFR flight from Fort Worth, Texas, to Champaign, Illinois, in a Piper Saratoga. He was descending over Rochester, Illinois, when he reported to Kansas City ARTCC that he was having severe chest pains and shortness of breath. He said he was hand-flying the aircraft. Conditions were marginal VFR with a broken layer at 1,300 feet and four miles visibility in fog and snow. Radar contact was lost. Witnesses saw the aircraft spin out of the clouds, with separate pieces falling to the ground after the main portion had descended.
An autopsy revealed the cause of death was atherosclerotic coronary artery disease. The pilot had been previously hospitalized in October 1982 for chest pains. He had extensive testing for possible coronary problems, but no evidence of heart disease was uncovered except for mild hypertension. He had a valid medical certificate, a private pilot certificate, and an instrument rating.
The specter of such in-flight incapacitation or impairment is the rationale for medical regulations and aviation medical examinations. Such an accident also highlights limitations of medical science in predicting accidents.
As noted below, the number of aircraft accidents resulting from medical incapacitation is small. Nonetheless, the FAA apparently sees the need to toughen medical standards for pilots. The agency has published a notice of proposed rulemaking that outlines more stringent medical criteria for many pilots, a position opposed by AOPA (see "AOPA Action," January Pilot, and "President's Position," December 1994 Pilot). As an aviation medical examiner, pilot, aircraft owner, and chairman of the AOPA Medical Advisory Panel, I assisted the association in preparing its comments to the docket. The results of my research clearly show that the high costs of stricter medical standards are not worth the small and perhaps unmeasurable increase in safety.
Preventing Medically Related Accidents
How frequently are medical conditions factors in aviation accidents? What are the most frequent medical factors? If medical regulations and examination procedures are changed, will accidents and fatalities be lessened?
The AOPA Air Safety Foundation's Emil Buehler data base provided answers to most of these questions. In the 10-year period from 1982 to 1991, there were 19,925 general aviation accidents. "General aviation" is defined as aircraft of less than 12,500 pounds not flown in scheduled service. Of these, the NTSB determined that medical factors contributed to only 379 accidents--or about 1.9 percent, fewer than 38 per year.
Since more than 98 percent of accidents have no medical factor, the majority of resources to reduce accidents should be directed toward the more common factors. It is generally accepted that more than 50 percent of accidents are caused by "pilot error," and weather is a factor in more than 25 percent. This strongly suggests that the current extensive medical regulations and 6,000 aviation medical examiners are either doing their job very well or are superfluous.
Assume that, despite the few medically related accidents, we wish to decrease that number by tighter medical standards and more comprehensive examinations. How could we do this?
Alcohol
Of the 379 accidents with medical factors, well over two thirds were due to alcohol and/or drugs. (Alcohol predominates six-to-one over drugs.) Unfortunately, there is no way that an examiner can prevent a perfectly healthy pilot from leaving his office with a fresh medical certificate in pocket, stopping at a bar, and then piloting his airplane while soused. In 10 years, 259 general aviation pilots did something just as foolish.
A 49-year-old supervisor called one of his employees to pick him up at the site of an automobile accident. The employee noted that his boss was drinking at the scene of his (first) accident. The boss then insisted upon being driven to the airport, and when they arrived, he insisted that they both go for a flight. The employee wisely declined the invitation to fly, but he was unable to prevent his boss from taking off solo in his Beech Bonanza. The flight lasted only two or three minutes until the aircraft struck electrical transmission lines while maneuvering. Toxicology of the dead pilot revealed a blood alcohol level of .325 percent, which is at least three times the level considered "drunk" by most authorities.
Another case: Earlier in the day of an accident which occurred in Leesville, Louisiana, the four occupants of an aircraft had been reported to the local sheriff's department as being drunk in a lounge. Despite their inebriated state, they successfully flew a Cessna 172 to De Ridder, Louisiana. After landing, the aircraft ran off the asphalt, bending both propeller blades. The resourceful occupants straightened the blades with a pipe wrench and then decided to celebrate at a nearby nightclub. All would have had a happy ending if they had not returned to the airport several hours later that dark evening. Though further burdened with alcohol, they attempted a second flight. It ended shortly after takeoff when the aircraft impacted trees in a near vertical attitude. The 47-year-old pilot and two of his three companions were killed; the other passenger survived with serious injuries.
And then there's the pilot who landed at Pueblo, Colorado, and asked the FBO attendant if any liquor stores were open. During the taxi ride back to the airport, he consumed about half a pint of a bottle's clear liquid contents. He then carried a brown paper bag with him to his aircraft. After starting the engine, he expedited his flight by attempting takeoff from the taxiway that connected the general aviation ramp with the intersection of runways 8L and 35. The Piper Comanche never became airborne. It ran off the end of the taxiway into rough terrain, and the pilot was seriously injured.
Accidents involving alcohol are often deadly. While there is no excuse for the fact that 1 percent of general aviation accidents involve alcohol, the rate compares very favorably to that for automobiles and boats--where more than 50 percent involve alcohol. Should Draconian measures be applied to all pilots because a few inexcusably think alcohol is acceptable in the cockpit?
Other medical Factors
Subtracting alcohol and drug-related accidents leaves 171 medically related accidents over 10 years. But 69 of the pilots involved did not have a medical certificate or had a certificate that was clearly invalid. Of these outlaws, more than two thirds were imbibing. If a pilot never bothers to obtain a medical certificate, no change in medical standards or increased thoroughness of an AME's examination will save his or her skin.
This leaves a target of 102 accidents involving medical factors that might have been identified during medical certification.
Eight accidents were caused by hypoxia; these pilots flew too high without oxygen or failed to use their oxygen equipment properly. Seven pilots succumbed to carbon monoxide poisoning because of leaky exhaust systems. The prevention of such accidents is obvious.
Seven pilots had visual impairment. This variegated group included a pilot who was advised by his family doctor to use an eye patch and see an ophthalmologist. He decided to test his vision in flight before seeing the eye doctor. One pilot was blinded by a bright dome light that could not be turned off. Another complained that he had to tilt his head back to read the altimeter with his bifocals.
And still another pilot knew he had visual disturbance at twilight but nevertheless attempted a flight in such conditions. His landing was also complicated by the front quarter of a freshly killed reindeer that somehow became wedged into the rear flight controls of his Pitts biplane, jamming the elevator. This was his third accident in that unlucky year, but he had not reported the previous two to the authorities in Alaska. It is unlikely that an aviation medical examiner could have prevented these accidents.
Over 10 years, seven pilots came to grief because of flu, colds, pneumonia, and nausea, and four more to motion sickness and vertigo. Three suffered strokes--possibly the only accidents that might be related to hypertension. Two were found after their accidents to have gunshot wounds. One pilot each had hypoglycemia, aortic dissection, a sutured laceration that ripped open, acute emphysema, pulmonary embolism, or hyperventilation. One pilot had a leg cramp while landing his Luscombe in a crosswind; he inadvertently stomped on the passenger side left rudder pedal instead of his own right pedal, resulting in a ground loop. It is unreasonable to exert effort to minimize factors that occur only a few times in 10 years.
Heart Disease
The only reasonable target for medical accident prevention is the 41 myocardial infarctions (heart attacks) that occurred in this time frame. Can we predict and prevent them from occurring in the cockpit?
About 336,000 general aviation (Class II and III) medical examinations are performed by AMEs each year. The FAA is proposing electrocardiograms (for Class II after age 35) and cholesterol screening (for Class I after age 50). Would it be worthwhile to add these two tests to *every* medical examination over age 40? As half the pilots are older than 40, this would entail some 168,000 augmented examinations each year for general aviation.
To do this, AMEs would need to purchase special equipment to transmit the electrocardiograms to Oklahoma City. Blood samples drawn would have to be sent to a clinical laboratory, with the results returned to the AME, pilot, and FAA. Assume an additional cost of $100 per examination for these two tests. Under this arrangement, more than $16.8 million will be spent annually to prevent some small portion of the four heart attacks that occur while flying each year. Is that the way we want to spend our resources?
Our ability to predict heart attacks in healthy people is poor, even using very sophisticated testing. A heart attack is often the first manifestation of cardiac disease. The pilot mentioned at the beginning of this article, who succumbed to a heart attack over Illinois, had undergone extensive cardiac testing five months prior to the accident. The tests did not identify the cause of his subsequent death.
We know some factors that increase risk: cigarette smoking, obesity, and lack of exercise. The effect of elevated blood cholesterol is not fully understood, though it may also be a factor in cardiac disease-- but no one has claimed it is a predictor of incapacitation. Clear benefits from lowering blood cholesterol seem to apply only to men who already have had a heart attack.
The electrocardiogram is a beguiling test and the mainstay of cardiac evaluation. However, it is a poor predictor of future cardiac problems in an otherwise asymptomatic individual. There are no other screening tests predictive of incapacitation that are generally accepted by the medical community as effective.
But assuming that, during an aviation examination, an AME could identify a pilot who was likely to have a heart attack within the next year, the chance that it would affect flight is slim. The average general aviation pilot flies 50 hours a year. As there are 8,760 hours in a year, there is less than a 0.6 percent chance--or one chance in 175--that incapacitation will occur while flying...and a much smaller chance that it will occur during a critical phase of flight. Remember that heart attacks were only one *factor* in the four accidents each year.
Is there need for new Medical FARs?
Many accidents had several factors, and the accident might have occurred even if the pilot did not have a medical event. A 61-year-old pilot decided to ferry an Aero Commander 680 twin from Bayport to Islip on Long Island, New York. The aircraft had not flown in 14 years. Appropriate maintenance, service bulletin compliance, and required lubrication had not been done. An engine failed, the pilot failed to maintain VMC, and both occupants were killed in the ensuing crash. The NTSB also listed "incapacitation" as one of the probable causes.
As an AME, I'd like to believe that a more probing examination and stiffer medical standards would improve the safety of flight. Unfortunately, that is not the case. I'd like to believe that more resources devoted to aviation medical certification will save lives. A few lives may be spared, but chasing medical factors is a most uneconomical method to procure safety aloft.
*Those wishing to comment on the proposed changes may write to the FAA, Docket No. 27940, Notice #94-31, 800 Independence Avenue SW, Washington, D.C. 20591. The comment period closes February 21. Comments should be submitted in triplicate.*
Ian Blair Fries, AOPA 551497, is an orthopedic surgeon with extensive medical and aviation-related credentials. He is an instrument-rated commercial pilot, senior aviation medical examiner, accident prevention counselor, and chairman of AOPA's Medical Advisory Committee. Fries is also a member of the Flying Physicians Association, Civil Aviation Medical Association, and Aerospace Medical Association.
Highlights of AOPA's opposition to the more onerous of the FAA's proposed changes to medical standards:
Specifications for "personality disorders, neurosis, and other mental conditions" remain far too general under the proposed revision.
Reducing blood pressure maximums from the current 170/100 (recumbent) to 155/95 (seated) would force many with borderline hypertension to undertake expensive drug therapies and cardiovascular workups to qualify for a medical certificate.
Applicants for second-class medicals, including most of the nation's flight instructors, would be required to undergo electrocardiograms every two years. Currently, that standard exists only for airmen holding first-class medical certificates.
The FAA's former standard relating to "convulsive disorder" would change to make a single seizure event disqualifying or subject to a special-issuance medical.
The NPRM does not recognize modern medical technology in cardiological areas such as heart valve replacement and pacemakers.
Requirements would force third-class medical certificate holders over 70years of age to submit to an exam every year.
AOPA supports some parts of the NPRM, such as changes to visual acuity and color vision standards, the administration of hearing tests, and the possible certification of diabetics whose conditions are under good control with insulin or oral medication.
[This message has been edited by inverted flatspin (edited 06 December 2000).]