Cessna 550 Citation II Maintenance Manual

Ground Power Unit HP High Pressure hrs JAA Time (24 hour clock) Joint Aviation Authorities JAR(s) kg(s) Joint Airworthiness Requirements kilogram(s) kt(s) knot(s) LDA MHz PEM psi QA QNH QRH Landing Distance Available Megahertz (frequency) Performance Engineer's Manual Pounds per square inch (pressure) Quality Assurance Altimeter setting giving altitude relative to mean sea level. Quick Reference Handbook RFFS Rescue and Fire Fighting Service SAM School of Aviation Medicine UTC Universal Time Co-ordinated VHF Very high (radio) frequency (ix) Air Accidents Investigation Branch Aircraft Incident Report No: Registered Owner & Operator Aircraft Type Nationality 3/96 (EW/C95/2/3) British Midlands Airways Boeing 737-400 British Registration Place of Incident Date and Time G-OBMM Overhead Daventry 52°20' North 001°10' West Latitude: Longitude: 23 February 1995 at 1205 hrs All times in this report are UTC Synopsis The incident was notified to the Air Accidents Investigation Branch (AAIB) at 1245 hrs on 23 February 1995 and an investigation began the same day. The investigation was conducted by Mr D F King (Investigator in Charge), Mr R W Shimmons (Operations), Mr C G Pollard (Engineering) and Ms A Evans (Flight Recorders). The incident occurred when the aircraft was climbing to cruise altitude after a departure from East Midlands Airport en-route for Lanzarote Airport in the Canary Islands. Following an indicated loss of oil quantity and subsequently oil pressure on both engines, the crew diverted to Luton Airport; both engines were shut down during the landing roll. The aircraft had been subject to Borescope Inspections on both engines during the night prior to the incident flight. The High Pressure (HP) rotor drive covers, one on each engine, had not been refitted, resulting in the loss of almost all of the oil from both engines during flight. There were no injuries to any crew or passengers. The aircraft was undamaged; both engines were removed and examined as a precautionary measure. The investigation identified the following causal factors: (1) The aircraft was presented for service following Borescope Inspections of both engines which had been signed off as complete in the Aircraft Technical Log although the HP rotor drive covers had not been refitted. 1 (2) (4) During the Borescope Inspections, compliance with the requirements of the Aircraft Maintenance Manual was not achieved in a number of areas, most importantly the HP rotor drive covers were not refitted and ground idle engine runs were not conducted after the inspections. The Operator's Quality Assurance Department had not identified the non-procedural conduct of Borescope Inspections prevalent amongst Company engineers over a significant period of time. The Civil Aviation Authority, during their reviews of the 'Company Procedures for JAR-145 approval, had detected limitations in some aspects of the Operator's Quality Assurance system, including procedural monitoring, but had not withheld that approval, being satisfied that those limitations were being addressed. Fifteen safety recommendations are made. 2 1 Factual Information 1.1 History of the incident 1.1.1 Aircraft dispatch and flight The flight crew reported for duty at 1055 hrs at East Midlands Airport to prepare for a charter flight to Lanzarote in the Canary Islands; departure was scheduled for 1155 hrs. On arrival at the aircraft, at approximately 1100 hrs, the crew commenced their normal pre-flight checks, during which they noted that the hydraulic power circuit breakers had been left open. The first officer went down onto the apron and asked the despatching engineer why they were not set. The engineer had reviewed the Technical Log before starting his refuelling and pre-departure checks and had seen that Borescope Inspections of both engines had been carried out during the previous night. These had been signed off as being completed satisfactorily. The engineer informed the first officer that, so far as he could see, there was no reason for the circuit breakers to be left open, so the first officer returned to the flight deck and closed them. With no outstanding items in the Technical Log, and after completing the normal pre-start checks, the crew started both engines. All engine parameters were checked as normal and G-OBMM left the stand at 1150 hrs. All the flight deck indications were normal during the taxi out to the runway and the aircraft was lined up on Runway 27 for take-off. The first officer was the designated handling pilot for the flight to Lanzarote and, using full power, he commenced the take-off roll, at 1157 hrs. During the climb, the commander was carrying out the normal non-handling pilot duties; these included monitoring of the engine instruments which initially indicated no problems. However, as the aircraft was climbing through approximately Flight Level 140, the commander noted that both engine oil quantity gauges were indicating about 15%; the indications were also fluctuating and continuing to decrease. As the crew were discussing this problem, both engine oil pressures began decreasing. Coincident with this, G-OBMM was transferred to London control on 131.12 MHz and, at 1204 hrs, the commander contacted London. The London Controller stated that he had positively identified the aircraft and confirmed the clearance to Flight Level 210. Shortly after this, at 1205 hrs, with the oil quantities continuing to decrease and the oil pressures now below 13 psi, the commander informed London that he had engine problems and wished to return to East Midlands Airport. The controller immediately cleared G-OBMM to level at Flight Level 180 and to turn left onto a heading of 010°M. By now, the oil quantities were indicating zero and the oil pressures were still decreasing. The crew informed Air Traffic Control (ATC) of the deteriorating situation and a "Mayday" was 3 declared. As the aircraft was turning left onto the designated heading, the ATC controller informed the crew that Luton Airport was the closest diversion and asked them where they wished to go. The commander then declared that he was diverting to Luton and the controller cleared G-OBMM to roll out on a heading of 120°M, and to commence a descent. The commander assumed the role of handling pilot, and the first officer was allocated the tasks of re-programming the Flight Management Computer and operating the radio. Radar and Flight Data Recorder (FDR) information indicate that G-OBMM levelled at Flight Level 180 at 1205.28 hrs and remained level for only 17 seconds before commencing a descent. During the descent and recovery to Luton, the ATC controller assisted the crew by minimising transmissions but ensuring that he passed them all essential information such as continuous descent clearances and weather information for Luton. Within the aircraft, the flight crew were working together to ensure that the aircraft was configured for the approach to Luton. The commander was using idle power and had made the decision that they would be making a Flap 15 landing. He decided on this flap setting because he was very conscious of the need to minimise power requirements due to the engine oil situation; both oil low pressure lights had illuminated 40 seconds after leaving Flight Level 180. The commander had called the senior cabin attendant to the flight deck and fully briefed her on the situation, including the fact that they were making an immediate diversion. In turn, the senior cabin attendant briefed the cabin crew and the cabin was quickly prepared for landing; the commander had already briefed the passengers that he was diverting to Luton. The approach was direct and uneventful, and the crew was given priority and all requested assistance by London and Luton ATC agencies. G-OBMM touched down on Runway 26 at Luton at 1214 hrs; touchdown speed was at the crew's assessed target of 170 kt and at the normal touchdown point. Immediately after landing, the commander selected idle reverse power and used maximum automatic braking; with the landing roll under control and after transferring electrical power to the Auxiliary Power Unit, the first officer, on instruction from the commander, closed down both engines at approximately 120 kt. The aircraft came to a stop on the runway and was quickly attended by the Luton Airport Rescue and Fire Fighting Service (RFFS). The flight crew maintained radio contact with ATC but were unable to establish radio communications with the RFFS on the 121.6 MHz frequency; however, verbal contact with them was quickly achieved through the open flight deck window and the commander took the decision not to carry out an emergency evacuation. 4 1.1.2 The RFFS remained on the scene and the passengers began disembarking through the front left door using the aircraft airstairs. Once the commander had disembarked, he noted that the cowls of both engines, and the underside of both wings and flaps immediately behind the engines were covered in engine oil. History of the maintenance during the previous night The aircraft was scheduled to undergo Borescope Inspections of the turbine sections of both engines, which was required every 750 operating hours. This was to be performed, by the Airline's Line Maintenance organisation, during the night of Wednesday/Thursday 22/23 February. The Line Engineer in charge of this night shift had also been on duty on the previous night. When he had made the handover to the day shift, on Wednesday 22nd, he had left a loose note for the day shift leader expressing his concern about the manpower expected to be available over the Wednesday/Thursday night relative to the predicted workload, which he knew to include the two 750 hour Borescope Inspections. However, when he came back into work, at about 1930 hrs on the Wednesday evening, he found that the manpower of the shift had not been supplemented. Instead of the nominal shift complement of six, there were only four on duty that night, two of whom, including the shift leader, were doing extra nights to cover shortfalls. Although the Line Engineer was in charge of the shift, he knew that he had to do the Borescope Inspections himself as he was the only Line Maintenance engineer within the Company, at East Midlands Airport, with the necessary authorisation. Since this inspection was to be done in hangar T2, some distance from where the bulk of the Line Maintenance work was done, but close to the Base Maintenance hangar, he elected to do this inspection first. Therefore, after organising the Line night shift's work, he picked up the inspection paperwork from the Line Office and went to the aircraft. The package of paperwork contained everything that he, as a Line Maintenance engineer, would have expected. Hanger T2, used for this inspection, was partially occupied by the engine and propeller workshops but one end was largely vacant. This hangar space was, however, insufficient to accommodate the Boeing 737-400, G-OBMM, completely. When the Line Engineer arrived at the aircraft, at about 2030 hrs, it had been pulled into the hangar so that the doors could be partially shut to almost touch the fuselage sides just ahead of the tailplane. Although the airstairs were extended, the slats and flaps were retracted and there was neither electrical nor hydraulic power available. As he needed no aircraft power and anticipated no other tasks being undertaken on the aircraft until the inspections 5