FINAL REPORT on an investigation of a serious incident with Cessna 172 aircraft, registration NoLZ-BVA, owned by Bulgarian Aeronautical Center Air Operator realized on 19.08.2007 at Plovdiv Airport. 2007
CONTENT Introduction 1. Factual Information...5 1.1 History of Flight...5 1.1.1 Flight Number LZ - BVA...5 1.1.2. Location of air occurrence...5 1.2 Injuries to Persons...5 1.3. Damage to Aircraft...5 1.4. Other Damages...6 1.5 Personnel Information...6 1.5.1 Aircraft commander student pilot...6 1.6.2. Airplane performance...8 1.6.3 Fuel...8 1.7. Meteorological information...8 1.8. Aids to navigation...8 1.9 Communications...8 1.10. Airport...9 1.11 Flight data recorders...9 1.12 Wreckage and impact information...9 1.13 Medical and pathological information...9 1.14 Fire...9 1.15 Survival aspects...9 1.16 Tests and research...9 2. Analysis...9 3. Conclusions...11 4. Safety recommendations...13
Abbreviations AAIU Air Accident Investigation Unit AC Aircraft AO Air Operator AOC Air Operator Certificate ARP Airport reference point ATrC Air training center САА Civil Aviation Administration BAC Bulgarian Aeronautical Center DME Distance Measuring Equipment FAA Federal Aviation Administration ICAO International Civil Aviation Organization KIAS Knots Indicated Air Speed MCM Maintenance Control Manual MD CAA Main Directorate of Civil Aviation Authority MM Maintenance Manual NDB Non-Directional Radio Beacon NTSB National Transportation Safety Board, USA RWY Runway SN Since new TDZ Touch Down Zone VOR Very High Frequency Omni-Directional Range Station
Introduction On the 09.08.2007 a student pilot of Cessna-172R aircraft, registration number LZ - BVA, conducted at Plovdiv Airport a solo training flight in the flight maneuvering area according to the Training Program - Section V, CPL(A), variant 1. After the end of the exercise he performed a landing approach to RWY 12. At touch-down the nose landing gear tire blew out, the aircraft changed the direction of movement, sprang and flew several meters, landed again and the propeller blade hit the concrete surface and its ends were deformed. The aircraft left the RWY in a 100 direction (about 30 less than the landing course) and went into the ground at 3m from the left-hand end of the runway. After a run of 57m the pilot returned the aircraft on the RWY and after 28m stopped. On the ground of the air occurrence notification from the AO and preliminary presented facts the air occurrence was classified by AAIU as an incident. After an in-depth inspection of the aircraft by the AAIU inspectors inconsistencies between the facts were established and significant deformations of the aircraft airframe. On the grounds of Article 16, Para.1 and p. 9 & 13 of Enclosure 7 to Regulation No 3 of the Ministry of Transport on air accident investigation AAIU has re-qualified the air occurrence as a Serious Incident and started an investigation in the interest of air safety. By order RD-08-416/13.09.2007of the Minister of Transport a commission for investigation of serious incident was appointed. Notified: AAIU, MD CAA, NTSB (USA), CESSNA AIRCRAFT COMPANY (USA). By letter with reg. No 10-01-124/31.08.2007 AAIU notified the Director General of CAA on re-qualifying of the air occurrence and the order of the Minister of Transport for the investigation of the serious incident. By letter with reg. No 10-50-282/31.08.2007 AAIU informed the manager of BAC about the re-qualifying of the air occurrence and the order of the Minister of Transport for the investigation of the serious incident. The materials related with aviation occurrence investigation have been classified under state file number No 07/19.08.2007 in the archives of AAIU. Air Operator: Bulgarian Aeronautical Center Ltd, City of Sofia, Air Transport Institute, Sofia Airport, 1540 Sofia, Bulgaria. The air operator possesses Air Operator Certificate (САО), issued by DG CAA and valid till 20.04.2008. The air operator possesses Air Training Center Certificate, issued by DG CAA and valid till 19.05.2008. Aircraft manufacturer: CESSNA AIRCRAFT COMPANY, USA. National and Registration Marks: LZ - BVA, according Certificate for Registration No1953/08.02.2005, issued by DG CAA. As to the moment of the air occurrence Cessna-172R aircraft reg. LZ - BVA is been owned by AO Bulgarian Aeronautical Center Ltd. Place and Date of Air Occurrence: Plovdiv Airport, ICAO code LBPD, coordinates: N 42 04' 04" and Е 025 51' 03", on 19.08.2007 at 11:49 hrs local time. Type of Flight: solo training flight in flight maneuvering area.
1. Factual Information 1.1 History of Flight 1.1.1 Flight Number LZ - BVA The flight mission was posed in accordance with the Pilot Training Program for conducting a solo training flight in flight maneuvering area according Exercise No 23. The preliminary preparation for the flight was performed on the 17.08.2007 from 14:00 till 16:00. In the preliminary preparation sheet from this date in the section Self-training Matters are set two matters of most general nature and they have no direct relation with the execution of the exercises planned: 21, 22 и 23 of the Program. In the Working-out section are reflected the elements for execution in the flight maneuvering area, but the parameters for execution of elements, such as: climb rate, order and altitude of occupation of the flight maneuvering area, range of altitudes for execution of the elements, speed and heading of lead-in and lead-out of the maneuver, minimum and maximum allowable altitudes and speeds of the flight in the flight maneuvering area, etc. In the Visualization section are not reflected all the planned elements, and those which are shown, are made schematically and in general view, having in mind that it is first time to show a phase of initial training of a pilot - instruction flight, check flight and solo flight. In the preliminary preparation sheet of the trainee pilot there is no section for In-flight Emergency Procedures, such as engine shutdown at different stages of the flight, fire, etc. and order for action in case of emergency situation. No specific parameters for approach and landing on RWY 12 and 30 of Plovdiv Airport are shown. The aircraft preparation for the flight is given in Para.1.6.1. After the execution of the elements of the exercise in the flight maneuvering area the pilot performed approach for landing on RWY12. According the pilot, the aircraft speed at the flare phase and immediately before touch down was 65-60 kt. The aircraft touched down at three points - two main wheels and nose wheel at 17m to the left-hand side from the center-line at an angle of 27 from the landing course, the nose tire was blown, the aircraft sprang and flew 7m, landed again on three points and the propeller blades scraped the concrete and were deformed. The aircraft continued its move, left the runway at joint No 43 and with heading 100 came out to the ground to the left-hand side of the runway. Moving alongside the runway, at joint No 51 it returned to the runway. At a distance of 131m from the first touchdown the aircraft stopped. During the first inspection by the AO it was determined that the tire of the nose wheel was blown up and the ends of the propeller blades were worn out and bended. The damages described in Para. 1.3 has been established afterwards. The aircraft damages after the air occurrence are shown in Enclosure 2. The pilot didn't suffer any injuries. 1.1.2. Location of air occurrence Plovdiv Airport, RWY12. 1.2 Injuries to Persons No injuries to persons. 1.3. Damage to Aircraft During the inspection at the place of the air incident the commission found out the following damages on the aircraft:
- Bending deformation on the propeller blades circumference, shown on Figure 1 and Figure 2 of Enclosure 2; - Rupture of outer and inner tire of the nose wheel, shown on the Figure 3 of Enclosure 2; - Deformations of the fire wall, shown on the Figure 3 of Enclosure 2; - Deformations of forward load-caring belt, shown on the Figure 4 of Enclosure 2; - Deformations of the sheeting of the lower surface of fuselage after the first load bearing belt, shown on Figure 5 of Enclosure 2. The above mentioned deformations require repair of aircraft airframe. 1.4. Other Damages No other damages. 1.5 Personnel Information 1.5.1 Aircraft commander student pilot, aged 20, with a valid medical certificate. 1.6. Aircraft information 1.6.1. Airworthiness information CESSNA SKYHAWK 172R aircraft, reg. No LZ BVA, was manufactured on the 13.12.2004 by CESSNA AIRCRAFT COMPANY - USA. The aircraft possesses Certificate for Registration. The Certificate for Airworthiness has been issued on the 18.04.2005. The last verification of the Certificate was made on 19.04.2007 and is valid till 18.04.2008. The aircraft has accumulated 1016.6 hrs since new till 19.08.2007 (before the serious incident). An engine Lycoming ІO-360-L2A, serial No L-31694-51А was installed on the aircraft with total engine operating time of 1016.6 hrs. In accordance with the life-timing instruction, enclosed to the Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline, an engine overhaul should be performed after every 2000 hrs. The engine has 983.4 hrs residual life till the overhaul. The power unit includes propeller McMauсСley IC235/LFA7570 model, serial No EB41809, installed by the aircraft manufacturer. Aircraft maintenance is performed on the ground of approved by CAA Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline. In implementation of this program on the 18.08.2007 a scheduled maintenance of the aircraft for 1000 hrs was certified, when according the aircraft clock of the tachometer the engine has accumulated 1008.4 hrs. The maintenance was performed by Maintenance Organization of Air Transport Institute, owner of Maintenance and Repair of Aeronautical Engineering Certificate No BG CAA 0006, issued on 22.11.2004. For the execution of this maintenance there is a record in the Customer Care Handbook of the aircraft and technical log book 000792 was fulfilled. AO Bulgarian Aeronautical Center has no contract concluded for maintenance with the Maintenance Organization of Air Transport Institute. Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline is compiled on the base of one of the three maintenance programs for C 172 aircraft, proposed in Part 5-00-00 of Maintenance Manual (ММ) of the aircraft. This is the program shown in Part 5-10-01. The program approved by CAA is for line maintenance, except the pre-flight preparation, and 50, 100, 200, 300, 400, 500, 600, 1000 hrs and annual inspections. AO Bulgarian Aeronautical Center uses for registration of the line maintenance a technical log book. The technical logbook fulfilled for the last flight when the occurrence has occurred, is under No 000804 and certifies the aircraft preparation for the respective flight. It was signed by the technical person and the aircraft commander. There were no failures noted in the preceding flight and no failures were revealed during the pre-flight check.
During the inspection of the documentation related with the aircraft maintenance the following ascertainments were found: 1. There was no failure recorded in all 429 technical logbooks, completed from the beginning of year 2007(04.01.2007) till the moment of the occurrence (19.08.2007). 2. During the certified on 18.08.2007 1000-hrs maintenance the working cards with intervals В, С, D, Е, F, G, O & T of the Maintenance Program were not executed, i.e. the maintenance was fulfilled in the scope of 50-hrs check. 3. During the interval between the last 100-hrs checks, determined according the reading of the clock of the engine tachometer 109.3 hrs, in the technical logs flight time of 137:31 hrs was written. 4. In the technical logbook No 000804 filled up after the aircraft inspection after occurrence, only the propeller deformation was registered and other damages of the aircraft, resulted from the occurrence, were not reflected. 5. The described in the Maintenance Program Maintenance Schedule was developed on the base of Revision 9 of aircraft MM, and as to the moment Revision 14 was published. The last amendments of the Program were approved by CAA on 14.03.2006, and Revision 14 was issued on 01.01.2007. 6. Some errors were made in compilation of working card for Check A, executed during the 1000-hrs check, certified on 18.08.2007: - The content of work No 792001, written into two positions in the working card, is not corresponding with the content of the work with the same number, written in Enclosure 1 of Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline. - Work No 801002 was written in two positions. 7. In the Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline was wrongly written the type of propeller used, where instead of 1C235/LFA7570 it was written IC235/ZFA7570. In the logbook for propeller maintenance, certified on 08.03.2007 (100- hrs check) to the end of records the serial number of the propeller was wrongly written as УВ 4809 instead of УВ 48109. 8. In the Maintenance Control Manual (MCM) of AO Bulgarian Aeronautical Center there were no enclosed contracts for maintenance with organizations approved according Regulation 145 in accordance with the requirement of Para.3.1. 9. In Para.0.3.1 of MCM is shown, that the required time for execution of the position Air Operator Manager is 2 man-hours per month. 10. In Para.0.3.2, p. а of MCM is written: Initial training of the personnel in point 0.3.6.1 should be received in courses at the Training Center according the requirements of regulations of CAA. There is no point 0.3.6.1 in MCM. 11. The determined in Para.1.2.4.1 of MCM maximum allowable changes of the determined in Maintenance Program period of inspections are not compatible with the given by the manufacturer in Part 5-10-00 of aircraft ММ, and all inspections over 100hrs are overstated. 12. In the aircraft logbook from 22.04.2007 a 100-hrs check was certified at reading of clock of the tachometer of 787,3, and the next 50-hrs check was executed on 02.06.2007 at reading of the clock of the tachometer 858,3, i.e. the envisaged by the manufacturer period of inspection was exceeded by 20 hrs. 13. In the aircraft logbook from 08.03.2007 was registered regular execution of 100-hrs check and in the filled up for the case technical logbook No 000750 from 14.03.2007 it was written execution of 50-hrs check. 14. In Para.1.2.1, p. B of MCM is written: Maintenance program of BAC's aircraft should be supported by the program, described in Para.1.10. This paragraph is headed Reliability Program and in it is written "Reliability Program is not applied to BAC". 15. In the content for Section 4 of MCM Examples of documents, tags and forms used are given 19 paragraphs, but in MCM itself on paragraph 4.1is given Technical logbook.
16. In Para 1.3.1 of MCM a number of activities are entrusted to Director of the Planning and Control of BAC Production Department, but in the structural scheme of Operator's organization, shown in Para.0.3.3.1, such a department doesn't exist. 17. In Para.1.11.2, p. E is written: "When a BAC aircraft is grounded outside of BAC base (this base is not determined in MCM) because of lack of spare part with respective certificate, it is permitted to use a spare part without such a certificate for only 30 hrs maximum or until the aircraft is transferred to Sofia Airport. It is more likely a decision of the Chief Engineer of BAC. The component should be replaced after specified time, unless the respective certificate is received. 18. Para.1.14 of MCM Notification for an incident is not pursuant to the requirements of Regulation No13/27.01.1999. 19. Para 2.1.2 of MCM is entitled Assurance of Quality Program, while АМС OPS 1.035 requires Quality Assurance Program. 1.6.2. Airplane performance According to the data shown in Aircraft Operation Manual: Aircraft maximum take-off mass - 2450 lbs. Aircraft maximum landing - 2450 lbs. Aircraft standard empty mass - 1639 lbs. Maximum allowable speed V NE - 163 kt. IAS. Maximum cruising speed V NE - 129 kt. IAS. Normal operational speed range 44 129 KIAS. Operational range with fully extended flaps 33-85 KIAS. Maximum allowable G-force with retracted flaps - +3,8G, -1,52G Maximum allowable G-force with extended flaps - +0.3G The aircraft is fitted with three-point fixed (non-retractable) landing gear with steerable nose wheel on shock-absorber leg. The pressure in the main tires of the aircraft according Part 12-18-00 of ММ is 29 PSI and the pressure in the nose tire is 34 PSI. The pressure in the shock-absorber leg is 45 PSI. This pressure should be checked during 100-hrs checks in fully extended position of the absorber. At this pressure and normal parking strut compression the visible part of the mirror surface of the shock absorber is 50,8mm (2 in.). At measuring of this value after the occurrence it was 27,5mm. It is a sign of reduced pressure of the gas in the shock absorber. 1.6.3 Fuel Fuel is aviation gasoline type 100LL. The maximum capacity of the fuel tanks is 56 US gallons (two tanks of 28 US gallons each), unusable fuel 3 US gallons, and usable fuel 53 US gallons. Before the last flight the aircraft tanks were refueled in full. 1.7. Meteorological information Day, visibility more than 10 km, wind 1m/s. 1.8. Aids to navigation Standard aids for Cessna 172R aircraft. Plovdiv Airport, RWY12: NDB+ VOR DME. 1.9 Communications Standard communication equipment for 172R aircraft. Communication equipment of working place at Plovdiv Tower.
1.10. Airport Plovdiv Airport is with the following coordinates of the airport reference point: N 42 04' 04" and Е 024 51' 03" and elevation of 182m. The airport has one runway with directions 127.23 and 307.23, marked as RWY 12/30 Place of aviation occurrence: TDZ RWY12. 1.11 Flight data recorders No flight data recorders are used on Cessna 172R aircraft. 1.12 Wreckage and impact information On Figures 6 & 7 of Enclosure 2 are shown the traces, left by contact of the aircraft main and nose tires and scratches of the propeller on the RWY. 1.13 Medical and pathological information The air occurrence was without any traumatological consequences for the pilot. 1.14 Fire No fire appeared. 1.15 Survival aspects The pilot was with safety harness. No fuel spillage resulted from the aircraft structure deformations. 1.16 Tests and research For the purposes of the air occurrence investigation the following was accomplished: - Examination of the air occurrence scene, presence of traces and fragments on the RWY; - Inspection of the aircraft and ascertainment of damages and destructions emerged; - Listening and analysis of the communication between the air controller at Control Tower of Plovdiv Airport and the pilot; - Investigation of the records on the pilot training and specific preliminary and preflight preparation for the flight; - Examination of the records in the aircraft operational documentation; - Examination of the operational documentation of the Air Operator; - Logical and probabilistic analyses of the possible causes for the air occurrence. The materials and results of tests and research are enclosed to Deed 07/19.08.2007 and are stored in AAIU archives. 2. Analysis After acquaintance with present facts and circumstances available and taking into account the pilot's and air traffic controller explanations in the day of air occurrence, the commission analyzed two main hypotheses about the origin of the serious incident: - Technical failure that leaded to a puncture of the nose wheel tire; - Committed error in the piloting technique during landing phase. On first hypothesis: The commission performed an inspection of the aircraft maintenance, in which the following was established:
- there was a certified pre-flight check in the aircraft documentation. This check included check of the nose landing gear and tire, the check was performed by a technical person and no failure was established; - a pre-flight check was performed by the pilot, who was accepted the aircraft and didn't register any failure; - the commission didn't establish a report on the failure or a deviation of the aircraft movement parameters during the listening to the radio exchange between the pilot and ATCo; - The length of the mirror surface of the shock absorber at parking position was 27,5mm, but it should be 50,8mm at normal pressure in the strut. It should be checked during a 100-hrs check, which should be performed on 18.08.07, but instead of this a 50-hrs check was performed. The low pressure of the shock-absorber contributes a bigger part of the energy of the hit to be absorbed by the tire, but this shouldn't lead by itself to the puncture of the tire; - During the inspection of the destroyed nose wheel tire it was established that its butch number 305С61-8 and serial number 50380634 were in accordance with the numbers in the technical documentation FORM 8130-3 of FAA and the condition of the tire didn't give ground for assumption for its destruction. On the ground of the above mentioned facts the commission accepted that this hypothesis is of low probability for origin of the air occurrence. On second hypothesis: The commission performed detailed inspection of the place of the air occurrence and the traces left by the aircraft at landing and the contact with the runway. It was established that the aircraft was touched-down in the touch-down zone, in the middle of first third of the RWY12 along the runway and at 17m to the left from the center line. The traces also gave the possibility to determine the direction of movement during the first contact with the runway - in heading 100, which was a difference of 27 from the landing course (LC), and the touch-down itself was at three points: two main tires and nose tire. At the contact with the runway surface the nose tire was left specific S-shaped trace. (Enclosure 2, Fig. 6.) After analysis of the aircraft movement and the system of nose wheel steering the commission assumed that it was possible if the pilot in order to rectify the direction of aircraft movement was deflected, still in air, just before touch-down, the rudder by the right-hand pedal, creating angel of slide and oriented the nose wheel in parallel with the runway direction. As a result of the sliding the velocity vector of the undisturbed flowing around the wing was decomposed and the effective part of the dynamic head was lessened and resulted in drastic loss of height during the flare and touch-down with overloading. At the contact of the landing gear wheels with the runway surface the forces of reaction of touch down were added to the outer forces acting on the aircraft. In aircraft rectilinear and uniformly retarded motion the reaction force is directed normally and lies in vertical plane. In this case the component force of the vertical reaction determines the resultant force of normal pressure of the aircraft on the runway and the component force parallel to runway determines the resultant force of rolling friction. In case of landing approach and contact between the aircraft and runway with an angle of sliding as a result of lateral acceleration and the aircraft mass a side reaction force is created, acting on the landing gear tires under an angle, equal to the angle of slide, with a coefficient of friction several times bigger than the coefficient at rolling. Depending on the order of contact of the landing gear tires with the runway, the lateral force created by the slide is distributed. S - shaped track of the nose tire is a result of the interaction of lateral friction force and inertial forces of aircraft mass, leaded to considerable overload resulted in destruction of nose tire. It is confirmed by the nature of the tear of the tire along the contour of the nose wheel rim.
After the nose tire cut as a result of normal g-load at touch down the aircraft separated from the runway, retaining the heading of movement at about 100, flew 7m and landed again on runway at the left-hand end line. From the pilot's explanations it was cleared that in order to prevent the aircraft departure to the ground he had operated the brakes of the two main wheels of the landing gear. In Flight Dynamics, author А.М. Mhitarian, second revised and supplemented edition, Para.8.7. Influence of design factors on the take-off and landing characteristics", page127, is е written: "For aircraft with nose gear it is not advisable to use the brakes in the initial phase of landing roll for preventing of drastic lowering of the aircraft nose." The moment created around the transverse axis as a result of the brakes operated and lack of amortization by the nose tire cut are the reason for the following contact of the propeller blades into the concrete in the area of joints No41-43 of RWY and subsequent deformation. (Enclosure 2, Fig. ) 7) At joint No 43 the aircraft left the boundaries of runway, rolled in parallel with the runway 64m and at joint No 51 it returned again to the runway, where it stopped. The distance from the first point of contact till the full stop of the aircraft is 131m. On the ground of the above mentioned facts the commission accepted the second hypothesis as probable for the origin of air occurrence. 3. Conclusions The technical investigation conducted, the results of examination and analysis give the grounds for the commission to make the conclusion, that the serious incident was a result from the following Main cause: Insufficient training of the pilot leaded to an error in pilot technique and operation of the aircraft at landing. Immediate cause: Landing approach with deviation of landing course and touch down with sliding leaded to destruction of the tire of the nose landing gear. During the process of investigation of the aviation occurrence the commission established also the following irregularities: 1. Flight Operation Manual, approved by CAA on 15.01.2005 was developed on the base of requirements of Regulation No 24 of Ministry of Transport and approved by CAA on 15.01.2005. As a structure (number and titles of chapters) the Manual reflects the general requirements to the document, shown in Enclosure No 5 of Regulation 24 for issuing of AOC. BAC possesses: Air Operator Certificate (AOC) and Air Training Center Certificate, where the activity specification is specified as Code AW 14 training flights. The contents of submitted and approved manual don't meet the requirements to this basic document, describing the structure, organization and activity of the specific AO in such a way as shown in Section 4/Part 2, p.4 of JAR-OPS and it doesn't specify the organization, functions, tasks and order of their fulfillment specifically as ATrC in accordance with the specification in the AOC. 2. The Training Manual (Part D) of BAC ATC, approved by CAA, is presented in Part I, Training of the Personnel, containing 11 sections, where Enclosure Section is without contents. The Manual doesn't contain the rest 10 sections. 3. The presented to the commission Pilot Flight Training Program isn't approved by CAA. 4. Air Accident Prevention and Flight Safety Program doesn't meet the requirements of JAR-OPS 1.037 и Safety Management Manual (ICAO Doc.9859) and it isn't approved by CAA. 5. There is no methodical working-out of the exercises on the base of Pilot Training Program PPL (A) for Cessna 172R aircraft, which should reflect the parameters for execution of the specific exercise, related with the methodical succession of the program and safe operation of this type of aircraft. Because of this reason the documentation of the preliminary preparation and
additional training for flight is not proper and it doesn't give possibility to make an assessment of the quality of the preparation and control, as well the readiness for safe conducting of the flight by the student., 6. АО Bulgarian Aeronautical Center has no contract concluded with Air Transport Institute Maintenance Organization. 7. The approved by CAA Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline is pertinent to the line maintenance, except pre-flight preparation and 50, 100, 200, 300, 400, 500, 600, 1000-hrs and annual inspections. 8. During the certified on 18.08.2007 1000-hrs maintenance the working cards with intervals В, С, D, Е, F, G, O & T of the Maintenance Program were not executed, i.e. the maintenance was fulfilled in the scope of 50-hrs check. 9. During the interval between the last 100-hrs checks, determined according the reading of the clock of the engine tachometer 109.3 hrs, in the technical logs flight time of 137:31 hrs was written. 10. In the technical logbook No 000804 filled up after the aircraft inspection after occurrence, only the propeller deformation was registered and other damages of the aircraft, resulted from the occurrence, were not reflected. 11. The described in the Maintenance Program Maintenance Schedule was developed on the base of Revision 9 of aircraft MM, and as to the moment Revision 14 was published. The last amendments of the Program were approved by CAA on 14.03.2006, and Revision 14 was issued on 01.01.2007. 12. Some errors were made in compilation of working card for Check A, executed during the 1000-hrs check, certified on 18.08.2007: - The content of work No 792001, written into two positions in the working card, is not corresponding with the content of the work with the same number, written in Enclosure 1 of Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline. - Work No 801002 was written in two positions. 13.In the Maintenance Program of Cessna 172R aircraft of Bulgarian Aeronautical Center Airline was wrongly written the type of propeller used, where instead of 1C235/LFA7570 it was written IC235/ZFA7570. In the logbook for propeller maintenance, from the maintenance certified on 08.03.2007 (100-hrs check) to the end of records the serial number of the propeller was wrongly written as УВ 4809 instead of УВ 48109. 14. In the Maintenance Control Manual (MCM) of AO Bulgarian Aeronautical Center there were no enclosed contracts for maintenance with organizations approved according Regulation 145 in accordance with the requirement of Para.3.1. 15. In Para.0.3.1 of MCM is shown, that the required time for execution of the position Air Operator Manager is 2 man-hours per month. 16. In Para.0.3.2, p. а of MCM is written: Initial training of the personnel in point 0.3.6.1 should be received in courses at the Training Center according the requirements of regulations of CAA.. There is no point 0.3.6.1 in MCM. 17. The determined in Para. 1.2.4.1 of MCM maximum allowable changes of the determined in Maintenance Program period of inspections are not compatible with the given by the manufacturer in Part 5-10-00 of aircraft ММ, and all inspections over 100hrs are overstated. 18. In the aircraft logbook from 22.04.2007 a 100-hrs check was certified at reading of clock of the tachometer of 787,3, and the next 50-hrs check was executed on 02.06.2007 at reading of the clock of the tachometer 858,3, i.e. the envisaged by the manufacturer period of inspection was exceeded by 20 hrs. 19. In the aircraft logbook from 08.03.2007 was registered regular execution of 100-hrs check and in the filled up for the case technical logbook No 000750 from 14.03.2007 it was written execution of 50-hrs check.
20. In Para.1.2.1, p. B of MCM is written: Maintenance program of BAC's aircraft should be supported by the program, described in Para.1.10. This paragraph is headed Reliability Program and in it is written "Reliability Program is not applied to BAC". 21. In the content for Section 4 of MCM Examples of documents, tags and forms used are given 19 paragraphs, but in MCM itself in paragraph 4.1 is given Technical logbook. 22. In Para 1.3.1 of MCM a number of activities are entrusted to Director of the Planning and Control of BAC Production Department, but in the structural scheme of Operator's organization, shown in Para.0.3.3.1, such a department doesn't exist. 23. In Para.1.11.2, p. E is written: "When a BAC aircraft is grounded outside of BAC base (this base is not determined in MCM) because of lack of spare part with respective certificate, it is permitted to use a spare part without such a certificate for only 30 hrs maximum or until the aircraft is transferred to Sofia Airport. It is more likely a decision of the Chief Engineer of BAC. The component should be replaced after specified time, unless the respective certificate is received. 24. Para.1.14 of MCM Notification for an incident is not pursuant to the requirements of Regulation No13/27.01.1999. 25. Para 2.1.2 of MCM is entitled Assurance of Quality Program, while АМС OPS 1.035 requires Quality Assurance Program. 26. Reduces pressure of the gas in the nose landing gear shock-absorber. 4. Safety recommendations 1. AO BAC should submit to CAA updated revision of FOM to reflect the requirements of JAR- OPS, Regulation No 24 of МТ/15.02.2000, rev. SG No65/05.07.2002, last amendment and addition in SB No 88 of 02.11.2007 on issuing of air operator certificate issuing with actual structure, functions and tasks according the specified in AOC and ATrC certificate specification of activity. Person responsible: ATrC manager Time: two months from the date of handing in the report. 2. ATrC BAC should submit for apporoval by CAA Complex Pilot Flight Training Program: PPL(A); CPL(A); CPL(A)/IR; FI(A); PPP/IR. Person responsible: ATrC manager Time: two months from the date of handing in the report. 3. On the ground of Art.20, Para4 of Regulation No 27/31.03.2000, rev. SG No 22/13.03.2007 ATrC BAC should submit for approval by CAA: - ATrC Operation Manual - Methodic for ground training of the flight personnel - Methodic for flight training at ATrC for the type of aircraft Person responsible: ATrC manager Time: three months from the date of handing in the report. 4. ATrC BAC should submit for apporoval by CAA Air Accident Prevention and Flight Safety Program, which should reflect the basic matters of ATrC Safety Control System and to meed the requirements of Regulation 13 на МТ/27.01.1999 on air accidents investigation and JAR-OPS 1.037, as well Safety Management Manual (ICAO Doc.9859) and Accident Prevention Program (ICAO, 2005). Person responsible: ATrC manager Time: two months from the date of handing in the report. 5. When compiling Exposition of organization of the control of continuous airworthiness BAC should avoid the shortcomings shown in points 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 and 25.
Person responsible: ATrC manager Time: three months from the date of handing in the report. 6. BAC should modify the Maintenance Program of Cessna 172R aircraft, removing the shortcomings shown in points 7, 11, 12 and 13. Person responsible: ATrC manager Time: three months from the date of handing in the report. 7. BAC Quality Assurance Program should be put in condition to assure the exclusion of shortcomings shown in items 6, 8, 9, 10, 11, 17, 18, 19, and 26. The Exposition of this system should be approved by CAA. Person responsible: ATrC manager Time: three months from the date of handing in the report. 8. AO BAC should conduct an extra annual inspection of Cessna 172 R aircraft, reg. No LZ BVA after the repair. Person responsible: ATrC manager 9. AO BAC а) to carry out : - Aviation occurrence analysis with the instructors and trainees; - An exam with the trainee pilot on aerodynamics of Cessna 172R aircraft; ТНЕ PILOT, S OPERATING HANDBOOK and Flight dynamics, phase Landing, b) to plan the trainee pilot after air occurrence realized and to perform two instructional circling flights and a check flight in flight maneuvering area. Person responsible: ATrC manager Time: one month from the date of handing in the report. In accordance with Art. 19, Para. 7 of Regulation No 3 of the Ministry of Transport on air accident investigaton, the persons responsible for execution of the propose safety measures should in the term shown to notify in written AAIU about the measures taken and the terms of their implementation.