Flight Safety Twin Otter Manual
Like other aircraft manufacturers, Xian went one step further in its MA60 twin-turboprop transport by incorporating an electromechanical lock as a backup to the mechanical stops that help prevent the power levers from being moved aft of flight idle in the air.
Flight Safety Twin Otter Manual
Although Xian had revised the master minimum equipment list in 2008 to include provisions for operating the MA60 with the electromechanical lock inoperative, the flight crew operating manual did not include any procedure for disengaging a functioning lock on approach. The report noted that manual disengagement of the electromechanical lock does not cause a caution light to illuminate or an aural warning to sound.
Development of the aircraft began in 1964, with the first flight on May 20, 1965. A twin-engine replacement for the single-engine DHC-3 Otter retaining DHC's STOL qualities, its design features included double-slotted trailing-edge flaps and ailerons that work in unison with the flaps to boost STOL performance. The availability of the 550 shp (410 kW) Pratt & Whitney Canada PT6A-20 turboprop in the early 1960s made the concept of a twin more feasible. A DHC-3 Otter with its piston engine replaced with two PT6A-4 engines had already flown in 1963. It had been extensively modified for STOL research. To bush operators, the improved reliability of turboprop power and the improved performance of a twin-engine configuration made it an immediately popular alternative to the piston-powered Otter which had been flying since 1951.
International aircraft publication standards of the General Aviation Manufacturers' Association and the Air Transport Association promote the use of a system of NOTES, CAUTIONS, and WARNINGS in flight manuals. A "NOTE" is meant to expand further on a topic; a "CAUTION" deals with matters that, if not strictly observed, could result in damage or destruction of equipment; and a "WARNING" directs attention to potentially critical information that, if disregarded, could lead to personal injury or loss of life. Although air crew may not know the exact definitions of NOTES, CAUTIONS, and WARNINGS, they are generally familiar with their relative importance through frequent exposure to them; that is, NOTES receive less attention than CAUTIONS and WARNINGS.
The Bombardier Corporation does not agree with the recommendation and contends that the present format and information in the manual is adequate. Bombardier also feels that changing the "NOTE" that highlights the fact that this manoeuvre did not meet the safety standard required under CAR 3 to a "WARNING" would not be appropriate in countries where regulatory approval has been granted.
The occurrence aircraft, a de Havilland DHC-6-300 Twin Otter, is a twin-engine turbo-prop aircraft that features a high wing with struts, a fixed landing gear, and an unpressurized cabin. The aircraft was configured with seating for 8 passengers for flight TIN223.
Two low-fuel-level caution lights are located on the caution light panel and are labelled FWD FUEL LOW LEVEL and AFT FUEL LOW LEVEL. Each light is controlled by a float switch in the related tank when a predetermined fuel level is reached. In level flight, the low level trigger point is 75 pounds of usable fuel remaining in the forward tank and 110 pounds of usable fuel remaining in the aft tank. An average fuel consumption rate for the DHC-6-300 is 10 pounds of fuel per minute. When both low-fuel-level lights illuminate, there are approximately 18 minutes of usable fuel left in the main fuel tanks before fuel exhaustion and loss of engine power. The aircraft flight manual (AFM)Footnote 7 advises pilots to land as soon as possible, and in no case later than 15 minutes, after illumination of both lights.
For the items that Air Tindi has deemed most critical for safety of flight, the verbal challenge and response technique is used. These checks require both flight crew to participate and these checks are not completed from memory. For the DHC-6, the following checks are verbal challenge and response checks: After Start, Run-Up, Taxi, Line Up, and Descent/Approach (Appendix B).
Making decisions as a crew, either before or during the flight, can be very effective. However, in a safety critical environment, such decisions need to be bound by objective procedures and hazard management, such as SOPs and checklists, to ensure that they are not affected by any associated group-based dynamics or biases.
Flight crew checklists prompt pilots to perform specific tasks, reducing the probability that they omit a safety critical step. At Air Tindi, checklists that contain the most critical items for flight safety are performed using the challenge and response technique. The technique increases the probability of detecting any omissions because when checklist items are read aloud by one pilot and responded to by the other pilot, omissions are more likely to be avoided. However, to be effective, the operating culture and crew resource management practices must encourage and reinforce the routine use of challenge and response checklists.
The DHC-6 aircraft flight manual provides performance figures on single-engine cruise fuel consumption per nautical mile. These numbers indicate that at 7000 feet above sea level (ASL) and an aircraft weight of 9000 pounds, with the remaining engine set to maximum continuous power, the fuel consumption per nautical mile would be 21% less if the flight was continued on 1 engine rather than 2.
There are no cockpit indications when REFUEL has been selected. Although the aircraft flight manual prohibits refuelling in flight, there are no defenses in place to prevent the switch from being placed in the REFUEL position.
If flight crews do not use the company reporting procedures to communicate safety concerns related to operational deviations, there is a risk that company management will be unaware of unsafe practices and unable to take corrective action.
None of the records recovered by the investigation team indicated that the failure of the CVR was noticed by the flight crew. The company operations manual did not contain direction to the flight crew requiring a periodic functional check of the unit. The occurrence flight was required by regulationFootnote 3 to have a functioning CVR.
The most recent audit of company operation and maintenance facilities, prior to the occurrence, was conducted by TC in October 1992. This audit included the areas of flight operations, flight watch/dispatch, passenger safety, transportation of dangerous goods, flight safety, airworthiness, and security. The audit team concluded as follows:
SGL is proud of its excellent safety record, and attributes its safe operations to the quality and experience of its field crews and flight operations crew, and management's ongoing commitment to safety. In order to ensure that company standards are met, all company aircraft are flown and maintained by permanent SGL employees while in the field and at head office. In addition to company training on specific aircraft, most of SGL's pilot's have successfully completed the Flight Safety course for the aircraft they fly. These courses entail a comprehensive ground school and flight simulator training.
Each flight crew consists of two pilots. Pilots shall use an aircraft checklist, standard calls, and procedures as described in the SOP Manual during all flight operations. The two pilots share handling duties in flight to mitigate the onset of fatigue. The aircraft shall be flown at all times within the limitations of the aircraft's flight manual and supplements along with any additional requirements imposed by the civil aviation authority.
There are no passengers permitted in the aircraft during flight. Only the flight crew and any personnel directly involved with the survey operation are allowed to fly and be designated as essential crew. Any crew members in addition to the pilots are thoroughly briefed on all flight safety procedures before the aircraft is moved. Essential crew may include observers mandated by a civil aviation or military authority.
The aircraft will conform to the required equipment list as described in the aircraft's flight manual and applicable supplements, in addition to references 1 and 6 for VFR, IFR, night, and over water flights, as applicable. This includes flight instruments, communication, and navigation equipment. The pilot in-command shall also ensure that equipment is carried sufficient for the survival of each person on board, given the geographical area, the season of the year and anticipated seasonal climatic variations. Each crew member is also provided with a personal EPIRB (emergency position indicating radio beacon) and a smoke hood/air filter. When operating over water or offshore (IAGSA Safety Policy Manual definitions) the aircraft shall be equipped with a life raft of sufficient capacity to accommodate all persons on board and equipped with a sea survival kit; a personal floatation device for each person on board; and a functional radio capable of two way communication with flight watch and/or ATS. During operations over cold water, a hyperthermia protection suit is provided for each person on board.
ETOPS Significant Systems means the aeroplane propulsion system and any other aeroplane systems whose failure could adversely affect the safety of an ETOPS flight, or whose functioning is important to continued safe flight and landing during an aeroplane extended diversion
1.2.1 This manual* applies to all twin-engine aeroplanes with a MCTOW of more than 8618 kilograms (19,000 pounds) for which a Canadian type certificate has been issued authorizing the transport of 20 or more passengers (whether or not the individual aeroplane is configured for 20 or more passengers) operated by a Canadian air operator in an air transport service. ETOPS does not apply to flights conducted wholly within Canadian Domestic Airspace.
For flights operating in the North Pacific area, which for the purpose of this manual, is defined as the area covering the Pacific Ocean areas north of 40ºN latitudes including NOPAC ATS routes and published PACOT track system between Japan and North America; 350c69d7ab