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General Aviation Safety
ON DECEMBER 24, 1968, ALLEGHENY AIRLINES FLIGHT 736, A CONVAIR 580, N5802, CRASHED AT APPROXIMATELY 2012 E.S.T., WHILE EXECUTING AN INSTRUMENT APPROACH TO RUNWAY 32 AT THE BRADFORD REGIONAL AIRPORT, BRADFORD, PENNSYLVANIA. THERE WERE 20 FATALITIES AMONG THE 47 PERSONS ON BOARD THE AIRCRAFT. SEE REC. NO. 69-25. THE AIRCRAFT MADE INITIAL CONTACT WITH TREES APPROXIMATELY 2.5 NAUTICAL MILES FROM THE END OF RUNWAY 32 AT AN ALTITUDE OF 2,081 FEET M.S.L. (66 FEET ABOVE GROUND LEVEL). THE AIRCRAFT THEREAFTER STRUCK A TREE AT 33 FEET ABOVE GROUND LEVEL AND ROLLED TO AN INVERTED POSITION BEFORE STRIKING THE GROUND. SEE APPROACH & LANDING ACCIDENTS IN FILE.
TO THE FEDERAL AVIATION ADMINISTRATION: 1. Pilots, operators and regulatory agencies should renew emphasis on, and improve wherever possible, cockpit procedures, crew discipline and flight management. 2. Both the air carrier industry and the FAA should review policies procedures, practices, and training toward increasing crew efficiency and reducing distractions and nonessential crew functions during the approach and landing phase of a flight. 3. Crew functions not directly related to the approach and landing should be reduced or eliminated, especially during the last 1,000 feet of descent. 4. During the final approach, one pilot should maintain continuous vigilance of flight instruments inside the cockpit until positive visual reference is established. 5. During approaches where less than full precision facilities exist, there should be a requirement that during the last 1,000 feet of final approach, the pilot not flying call out altitude in 100-foot increments above airport elevation. 6. There should be a requirement to report indicated altitudes to air traffic control at various points in the approach procedure, such as the outbound procedure turn and at the outer marker position. 7. The aviation community should consider expediting development and installation of audible and visible altitude warning devices and the implementation of procedures for their use. 8. Altimetry systems should be reassessed with particular regard to their susceptibility to insidious interference by forms of precipitation. 9. The possibility of development of additional altitude warning systems, external to the aircraft, should be explored. One possibility is a high-intensity visual warning red light beam, projected up along and slightly below the desired approach glide slope, to warn of flight below the desired path. 10. Development is needed in the fields of radio/ radar, and inertial altimetry and CRT/microwave pictorial display approach aids as possible improved replacements for the barometric altimetry system in the near future. 11. Modified use of existing approach radar should be further studied with regard to its adaptability as a surveillance (accident prevention) tool for nonprecision instrument approaches (e.g., to monitor automatically and warn against the descent below desired glidepath of any aircraft in the final descent mode). 12. There should be increased surveillance and more frequent and more rigorous inspection and maintenance of altimetry systems by both the air carriers and the FAA. 13. Certification requirements and procedures should be reexamined to determine if there is a possibility of a single failure mode of nominally dual systems which, when combined with an already existent passive failure or inadequate cockpit procedures, can invalidate dual failure protection features.
Original recommendation transmittal letter:
Closed - Acceptable Action
Bradford, PA, United States
Allegheny Airlines, Inc., Convair 580
Addressee(s) and Addressee Status:
FAA (Closed - Acceptable Action)
Safety Recommendation History
-From Joseph J. O’Connell, Jr., Chairman: I have your letter of January 27, 1969, commenting "both favorably and unfavorably" on our safety commendation of January 17, 1969, addressed to David D. Thomas, FAA Acting Administrator. I can readily understand that ALPA would be sensitive to anything that might impute less than meticulous attention to his task by any ALPA flight crewmember. Such was not, of course, our intention or the thrust of our letter, although I am sure you would agree, on reflection, that such inattention can occur, however rarely. I might suggest that the quotation in your letter, taken out of context as it was, creates precisely the impression you avow a desire to avoid, and to correct any misapprehendsion your letter may have created I quote what we actually said in this connection: "It is clear that had all ground and airborne navigational systems been operating accurately and had the flight crews been piloting with meticulous reference to properly indicating flight instruments, these accidents would not have occurred." The underlined part is what your letter quoted and obviously tends to pervert both what we said and what we meant.
This is in reply to your letter of 19 June 1969, in which you provided details on the possible modified use of existing Precision Approach Radar (PAR). A meeting was held on 24 June 1969, with Mr. E. King Stodola, of the Reeves Instrument Division of the Dynamics Corporation of America, who explained his proposal to representatives of the various agency Services attending. The Reeves system would monitor approaching aircraft through the PAR and automatically sound an alarm in the control tower whenever a gross lateral or vertical deviation from a preselected safe envelope occurs during the final approach. Other information such as distance from the runway, altitude, and ground speed could also be furnished. Use of this system would require appropriate information to be relayed to the pilot by the control tower. As you know, PAR has primarily been used at civil airports as a monitoring aid for ILS approaches, and we have very little experience in using it as a monitor for nonprecision approaches. Our experience with regard to monitoring ILS approached has shown that PAR adds little to safety and increases the workload of the already overburdened traffic controller--as would the Reeves proposal. One of FAA's long-range goals for improving safety and efficiency is to establish an ILS at all air carrier jet airports. Our five-year plan calls for 150 additional instrument landing systems for each of the years 1971 through 1975--or a total of 750. These systems will be installed on a priority basis subject to any budgetary constraints. Accordingly, we do not concur in the use of a modified PAR as a monitor for non-precision approaches, as recommended in your letter of 17 January, 1969, for the follwoing reasons: 1. It is more expensive than ILS; todays estimates for a basic PAR are approximately $780,000 as opposed to about $81,000 for a low cost ILS installation. 2. Installation of PAR at non-ILS airports would be limited to those airports equipped with a control tower. In view of the foregoing, we plan no further action with respect to the Reeves proposal.
This is to provide additional details on the possible modified use of existing approach radar as requested in your letter of February 6, 1969, page 3, item 10. In effect, we were calling for an exploration of the possibilities of modifying and automating the detection capabilities and the simplification of operatoinal aspects of already existing Precision Approach Radar equipment. We envision such an application as having the capacity to monitor automatically and warn against the descent below desired glidepath of any aircraft in the final descent mode. Mr. John Carroll of our staff discussed the essentials of this part of our recommendation of January 17, 1969, in a telephone conversation with Mr. Hugh Waterman of your Flight Standards Service last month. Mr. E. King Stodola of the Reeves Instrument Division of Dynamics Corporation of America, Garden City, L.I., New York, recently brought to our attention just such an application. We have asked him to get in contact with you. We are continuing to study the overall safety problems associated with the IFR approach and landing phases of flight and altimetry as outlined in our letter of January 17, 1969. We plan to be in further contact with you as our study progresses.
2/6/69 The following is a summary of the FAA's response: a. The FAA reiterates their immediate concern and has initiated a program of follow-up action in the areas of procedures, and cockpit discipline and vigilance. B. FAA inspectors have been directed to review, on a continuing basis, cockpit check lists and procedures to assure that minimum checking will be done during the more critical periods of flight, such as departures, approaches, and landings. C. FAA believes the airlines require all cockpit check procedures to be completed well before the last 1000' of descent, however, the FAA inspectors are to double check and take action where warranted. D. FAA inspectors have been directed to assure that cockpit check procedures are arranged so that the pilot flying devotes full attention to flight instruments. In an FAA wire to all u. S. Airline presidents, 12/30/68, FAA stressed crew vigilance and cockpit discipline. E. The FAA had asked the air carriers to adopt a requirement that the pilot not flying call out, during the final 1000' of the approach, 500' above field elevation, 100' above minimums and minimums. The FAA believes this procedure is preferable since it serves to keep cockpit conversation to a minimum, assure pilot altitude awareness, and reduces pilot workload. F. The FAA indicated that the pilot reporting of altitudes during instrument approaches would significantly increase radio frequency congestion and increase crew and controller workload. The FAA believes their efforts in pilot training and education will prove to be the most beneficial course of action. G. The FAA adopted a rule, Sept. 1968 requiring altitude alerting devices in jet aircraft by Feb. 28, 1971. H. The FAA plans to participate with NASA and the aviation industry in an assessment of possible failure modes of the altimeter static systems. The FAA reported that development and testing is required for approval of system modifications and at this time they know of no practical replacement for the barometric altimeter. I. The FAA reported that a high intensity visual warning red light beam on approach and glide path would not provide complete information concerning the optimum glide path as does the visual approach slope indicator (VASI) system which is installed at many runways throughout the country. The FAA plans to continue to install these systems in accordance with current criteria within the limits of funds appropriated for this purpose. J. The FAA reported that the use of inertial altimetry could be investigated, but must be considered as a long range research and development program. The cathoderay tube (CRT)/microwave pictorial display (radar mapping) has been evaluated by the military as an additional approach aid monitor but as yet the FAA does not have the detailed information because this equipment had been classified until recently. The FAA plans to look into the matter further. K. The faa requested additional information to clarify this part of the recommendation. (on march 17, 1969, bureau personnel informally clarified intent to FAA flight standards service personnel via telecon).
-From Theo. G. Linnert, Director, Engineering and Air Safety Department, Air Line Pilots Association: We have read your January 17th letter to Mr. D. D. Thomas with a great deal of interest. We would like to comment both favorably and unfavorably. We were very pleased that on page two third paragraph• from the bottom refers to a "Reassessment of Altimetry Systems". The entire contents of this paragraph has our complete approval and appreciation. Altimetry development and reliability is a subject which the Association has been stressing as in urgent need of attention. We are also pleased to see NTSB urging the developing and installation of "Audible and Visual Altitude Warning Devices", since we have been on record for many years in regard to pointing out a demonstrated need exists for such devices. We continue to be greatly concerned that the type of accidents continuing to occur all too frequently during an approach to a landing are apparently no different than those that have been occurring for many years due to the lack of the best available equipment and landing aids both in the airplanes and guidance from ground installed electronic landing aid equipment. The Association we believe is justifiably concerned to any inference such as contained in the NTSB letter quoted as follows: "Had the flight crew been piloting with meticulous reference to properly indicating flight instruments, these accidents would not have occurred." All pilots be they private, military or airline, fly their airplanes with meticulous care while making an instrument approach toward a landing for obvious reasons. Since instrument flying occurs without any visual reference to the ground the success of an instrument flight is dependent upon the "Properly Indicating Flight Instruments". We believe the choice of wording with regard to a pilot not using meticulous reference to properly indicating flight instruments can be inadvertently misleading to the public by inferring carelessness or negligence. We are also concerned that the NTSB letter infers that there is not sufficient emphasis in using recognized good operating practices. We refer to the paragraph that follows: "In this light, and with the number and frequency of approach and landing phase accidents under similar weather and operating environments, we believe that certain immediate accident prevention measures need to be taken. We believe that preliminary to the successful completion of our investigation into the factors and causes of the recent rash of accidents, renewed attention to, and emphasis on recognized good practices will tend to reduce the possibilities of future accidents." Our comments to the above are that we believe neither the carriers nor the pilots overlook using any "Recognized Good Practices". Here again, there is an inference which is misleading to the lay public and airline passengers. In our view the most tangible means that would immediately "tend to reduce the possibility of future accidents" is a program for expediting installation of improved landing aids and getting on with the long delayed need for updating our airports so that the new airline transports are not squeezed into obstruction-bound short runways. Overcoming airport obsolescent requires the same ruthless program that is used to make such remarkable progress in overcoming highway obsolescence. The Association points out that there are approximately 6 million takeoffs and landings annually by airline pilots and thereby indicating a high degree of professional airmanship and also indicating that when accidents do occur in the vicinity or on an airport the incident or accident should be carefully investigated with particular emphasis on the possibility of instrumentation reliability, lack of landing aids, or lack of airport safety standards, such as inadequate runway length, runways surrounded by obstructions and a lack of sufficient numbers of runways to minimize the hazards associated with take offs and landings on slippery runways when strong cross winds occur. Again we commend the NTSB for bringing forth several items requiring immediate attention which will enhance air safety. We also point out that while we favor providing the public with information regarding the cause of airline accidents we respectfully recommend that the NTSB would do well to coordinate with other segments of the airline industry such as the ATA and ALPA. This would enable obtaining the view points of other aviation organizations vitally interested in air safety for consideration by the NTSB when providing information for the public relating to airline accident causes. Rest assured of our interest and appreciation for your continued cooperation in our mutual efforts to increase air safety.
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