Portal:Civil Aeronautics Board

“ It is the established practice of most of the major air carriers to provide a definite procedure by which all essential instruments and controls are checked at certain specified times during operation. This is usually accomplished by means of a check list upon which the instruments and controls are listed and is so firmly established as to be a matter of routine. Had such a formal procedure been in effect at the time Trip 21 was performing an instrument approach at Atlanta, a routine check would have revealed such an error in altimeter reading as appears to have been involved in this case. ”

“ Aircraft, while on final approach to land, or while landing, have the right-of—way over other aircraft in flight or operating on the surface. When two or more aircraft are approaching an airport for the purpose of landing, the aircraft at the lower altitude has the right—of-way, but it shall not take advantage of this rule to out in in front of another which is on final approach to land, or to overtake that aircraft. ”

“ The experience of pilots flying in the vicinity cannot be relied upon completely in arriving at a conclusion as to the presence of turbulence. Experience shows that of two airplanes flying at the same altitude at the same time, a very short distance apart, one may encounter very severe turbulence while the other may be operating in comparatively smooth air. Therefore, it is impossible for us to arrive at a definite conclusion that the pilot of Trip 19 was flying through conditions of severe turbulence just prior to the crash. ”

“ All events leading up to impact, including the final radio transmissions from the flight, indicate that the crew was not concerned with and totally unaware of a dangerously low altitude situation. In examining the many potential ramifications involved in the aircraft's deviation from the desired altitude profile one obvious possibility is a misinterpretation or misreading of the information being presented on the altimeters. It is noted that the drum altimeter has been in operation for many years and is considered by all segments of the industry to be an accurate, highly reliable instrument. ”

“ When an airplane takes off with a weight in excess of the designated standard weight, the weight of the airplane must be reduced by gasoline consumption, prior to arrival at its next scheduled stop, to the extent necessary to bring it within the standard weight for landing. If sufficient gasoline had not been consumed between time of take-off and any emergency landing, gasoline can be dumped by the use of tested and approved dump valves in order to reduce the total weight to the approved weight for landing. ”

“ While it is impossible to determine whether or not mere visual observation of the cloud mass would have given warning that it possessed unusual characteristics, there is enough possibility that it might have done so to cause unfavorable comment on the lack of evidence of any concern on the pilot's part for the making of the closest possible examination of the characteristics of the storm, and of its apparent lateral extent, before entering it. ”

“ It is hazardous to fly for an extended period of time in a turn where all vision to the right side of the aircraft is obscured by the structure. Lieutenant Jones testified that he had been in the final turn for a minute of a minute and a half which at 220 m.p.h, would amount to as much as 51⁄2 miles. In view of the fact that a light haze existed, which reduced the visibility at the altitude of collision to about 6 miles, Lieutenant Jones' judgment in so prolonging the turn was faulty. ”

“ The only evidence in the record which suggests that one motor might have failed at that time is the statement of one witness, an airline pilot, who thought that the maneuver performed by the airplane resembled a stall aggravated by the use of the opposing motor. ”

“ In such weather conditions, and any conditions of limited visibility, the lighting system on the Cincinnati Airport is wholly inadequate to guide a pilot to a safe landing. There are no approach lights or runway lights which can be used by the pilot as a means of maintaining his correct heading after passing the boundary of the field. The only guides which a pilot has to assist him in maintaining alignment with a runway are two green lights at each end of the runway. ”

“ With respect to providing an en route flight weather information, one dispatcher said, "If the trip is operating in a scattered thunderstorm condition, the likelihood of any extended period in solid cloud is almost negligible. If he is operating where you would expect solid IFR conditions, it is a condition that requires all of the information he can get." It was stated that because many Capital aircraft are not radar equipped there was no distinction in the information furnished the en route flight based on this equipment. ”

“ The reasons given were that in climb the aircraft is limited in its maneuverability, and that the descent configuration would help keep the opposing traffic in sight.
If a pilot does undertake an avoidance maneuver with inadequate information, he cannot tell what effect it will have on the probability of collision. Once he has begun the maneuver, he no longer has the fixity criterion, nor can he knows when to end the maneuver. ”

“ If the fuel lines are moved inboard toward the center of the airplane, they will then be susceptible to rupture by items in the cargo compartment in the event of a belly landing which is the more conventional type of damage anticipated in emergency landings. We note in the Salt Lake City accident that the bottom of the fuselage was crushed upward approximately 20 inches. It is for this reason that the fuel lines were initially located in their present position. It is recognized that the fuel lines can be strengthened and their resistance to impact or shearing type failures can be improved. ”

“ Therefore, it can be postulated that an order to continue the flight by visual means during the final portion of the approach a rapid descent became necessary to remain below the clouds and to keep the ground and/or airport beacon in sight. If both pilots were concentrating on conditions outside the cockpit, and the altimeters were unmonitored, it is possible that the descent was continued until contact with the ground was unavoidable. Power was added by the crew when it was realized they were at a dangerously low altitude. However, the power application was too late to prevent ground impact. ”

“ There is no reason to believe that any electrical effect of lightning other than accoustical shock may have been even a contributing cause of the accident.
The optical effect of lightning, or of any sudden and bright light, is well known. Mrs. Everhart testified, that the lightning flash which occurred in the vicinity of the airplane while she was watching from a distance of about 11⁄2 miles was so brilliant that she was blinded for a brief time during which she lost sight of the airplane. ”

“ Under Part 60 of the Civil Air Regulations, a pilot would be expected to clear his position in preparation for landing, and clear himself in each turn, should he make turns to the base leg and final approach. In the absence of a sequence and on the basis of the clearance received, it was not imprudent of the Cessna pilot to assume that the area was clear of conflicting traffic. Nevertheless, the pilot of the Cessna 140 should have observed the Aeronca L-16 as he entered the downwind leg if he had properly cleared his position as he entered. ”

“ However, as we have pointed out, Caption Perry gave no evidence of knowledge of an emergency and took no measures to combat it. The probability of the accident being due to loss of power from carburetor ice is also refuted by the fact that for the last 1500 feet the plane is known to have proceeded in practically level flight and to have crashed with normal power being developed by the engines. Thus all of the circumstances surrounding the flight indicate that carburetor ice was not present, or, if present, was not of such a degree as to be a contributing factor in the accident. ”

“ The air carrier shall be responsible for qualifying each first pilot for the route over which he is to fly aircraft in scheduled air transportation as first pilot. Such qualification shall include a thorough knowledge of all of the instrument approach procedures, the terrain, any obstructions or congested areas, and the physical lay-out of the airport and approaches at each regular, provisional, refueling, and alternate airport approved for the route. ”

“ The basic responsibility of Airway Traffic Control is to prevent aerial collisions between aircraft operating under instrument conditions. Decisions on whether a flight is advisable, or may be made with safety, under the weather conditions existing are the responsibility of the pilot and the air carrier dispatcher. Notwithstanding this, Airway Traffic Control suggested to the United dispatcher that he advise Captain Scott that an air carrier airplane which has preceded him had accumulated an inch and a half of ice while coming through the overcast. ”

“ Data developed by an independent research agency, under government contract, revealed that the rate of response to elevator deflection has a profound effect on the behavior of the aircraft from the pilot viewpoint. This mode of motion, the longitudinal short period mode, has a one to five second period and is involved in the maneuvering of the aircraft. As the short-period frequency decreases, a slower response is experienced, and the initial motion is not a good indicator of what the final response will be. ”

“ The purpose of these previsions is completely defeated if an airline fails to provide adequate dispatchers thus requiring them to communicate over such long distances that they cannot secure current information and by requiring them to have so many flights under their control that they cannot pay adequate attention to any of them. If a trained dispatcher had been located in the Florida sector of Route 6, he would have recognized the significance of Captain Meyers' 8:32 A.M. radio message that he was on instruments and encountering heavy turbulence. ”

“ In undisturbed air, at 6000 feet, the maximum rate of climb of a fully loaded aircraft of the type involved in this accident is approximately 600 feet per minute at take-off power. Even with one engine dead, the maximum rate of climb would be over 100 feet per minute. If the airplane had flown out of a rising current in front of the storm and directly into rapidly descending air, approximately as it entered the rain, it is conceivable that it might have been impossible, even with the application of full power, for the pilot to avoid a rapid loss of altitude. ”

“ However, during flight the responsibility for the safety of the ship is primarily on the pilot. A dispatcher, insofar as his control of a flight permits, must make certain that it is conducted in accordance with the Civil Air Regulations. Pertinent in this case are the regulations forbidding an air carrier aircraft from landing or taking off from any airport along the route except under weather conditions above certain ceiling and visibility minimums set forth in the weather letter of competency issued to the air carrier operator by the Civil Aeronautics Administration. ”

“ Here again, as in the case of lightning, direct research is difficult, but a substantial amount has already been accomplished. We believe it important that the existing store of knowledge of the nature of atmospheric turbulence, of its structure when its severity is at a maximum, and of its effect on the flight performance and the control of the aircraft should be extended as rapidly as possible. ”

“ Methods should be developed for collecting and correlating the experiences that airplane pilots may have with exceptional turbulence, or other unusual atmospheric conditions. It happens from time to time that a pilot, military, airline, or private, observes some exceptional atmospheric condition, or some exceptional effect upon the flight of the aircraft. The ability of pilots to benefit from one another's experiences in such matters is quite largely limited to the results of informal report. ”

“ The stall characteristics of the DC-3 with power off are considered to be quite satisfactory. When a stall occurs it develops at the center section before progressing to the wing tip and good lateral control is maintained almost to the stalling speed. An incipient stall is accompanied by vibration and tail buffeting which develops at a speed of about five miles per hour above the actual stalling speed. There is no marked tendency for the airplane to roll off in either direction, and it may be held in the stall without rolling unless the stall has been induced by pulling the nose up sharply. ”

“ The past record of safety of air transportation within the United States, extending to over 130,000,000 miles of transport flying without serious injury to any person in the 17-month period immediately preceding the present accident and to thirteen years of operation without fatal accident by Pennsylvania Central Airlines and its predecessors, is a sufficient evidence that only the highly exceptional or the hitherto unknown would produce so tragic an effect. ”

“ Although pilots are not in agreement as to the degree of effect of ice upon the performance of the aircraft, they all agree that ice does raise the stalling speed. Wind tunnel tests under simulated icing conditions confirm this conclusion, which also follows from a consideration of the basic theory of wing action. The stall is not accompanied by the usual visual or mechanical warnings and may occur at an attitude which is not expected by the pilot. Tail buffeting is often decreased or entirely eliminated. ”

“ In seeking to determine the course of events that led to this accident, in the absence of any direct testimony from any actual observer on board the aircraft and in view of the circumstantial evidence of record, we are obliged to look for the extraordinary, and to examine into the possibility and probability of occurrences that are so rare in practical operating experience as to be highly obscure, if not virtually unknown. ”

“ It is improbable that a momentary failure of one engine to take the throttle could have resulted from cooling of the motors, because, according to pilot testimony, one of the principal advantages of the drag approach under partial power is that the motors remain warm and available for an emergency.
The evidence indicates that at the time of impact both motors were under little, if any, power, and the similarity of their condition indicates that both engines were doing exactly the same thing at that time. ”