SAFETY INVESTIGATION .1 BASIC SAFETY CONCEPTS
Chapter 2. Basic Safety Concepts 2-31
2.9 SAFETY INVESTIGATION 2.9.1
The investigation of safety occurrences is an important component of the management of safety. Chapter 7 characterizes the accident investigation process as the ultimate goalkeeper of system safety. The value of safety
investigation is, however, proportional to the approach under which the investigation is carried out. 2.9.2
The traditional approach discussed in 2.3.8 describes what is known as a safety investigation for “funereal” purposes:
a to put losses behind; b to reassert trust and faith in the system;
c to resume normal activities; and d to fulfil political purposes.
2.9.3 The concept of occurrence causation described in Section 2.4, and the notion of the organizational
accident discussed in Section 2.5, are linked to what is known as safety investigation for improved system reliability: a to learn about system vulnerability;
b to develop strategies for change; and c to prioritize investment of safety resources.
2.9.4 In closing this chapter, one example of each approach to safety investigation is schematically presented.
Both examples relate to the investigation of accidents.
Safety investigation for funereal purposes
2.9.5
The facts
• An old generation four-engine turboprop freighter with a flight crew of two as sole occupants flies into
severe icing conditions during a night-time domestic flight. •
As a consequence of ice accretion, engines 2 and 3 incur a flameout, and seven minutes later engine 4 fails. The flight crew manages to re-start engine number 2.
• The aircraft is now in a condition of considerable asymmetrical power, with both engines on the left
side delivering power and the two engines on the right side unserviceable. The flight crew experiences serious difficulty in controlling the aircraft.
• Because of the high demand on the aircraft’s remaining sources of electrical power, electrical load
shedding is not possible, and the electrical system reverts to battery power. The flight crew is left with limited emergency instrumentation to maintain control of the aircraft, limited radio communication and
limited navigation capabilities.
• While attempting to conduct an emergency landing, battery power is depleted and all electrical power
is lost.
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• All that is left to the flight crew is the self-powered standby gyro, a flashlight and the self-powered
engine instruments. •
The flight crew is unable to maintain controlled flight, and the aircraft crashes out of control. 2.9.6
Findings of the safety investigation
• The flight crew did not use the weather radar to avoid the icing conditions.
• The flight crew did not consult the emergency checklist to resolve the powerplant and electrical system
malfunctions. •
The flight crew was faced with a demanding situation requiring decisive thinking and clear action. •
The aircraft was flown into icing conditions which exceeded certification conditions for the engines. •
The flight crew did not request diversion to a closer aerodrome. •
The flight crew did not use correct phraseology to declare an emergency. •
The flight crew practised poor crew resource management CRM. •
There was mismanagement of aircraft systems. •
The presentation of visual information on the emergency checklist was poor. •
There were issues regarding internal quality assurance procedures for flight operations. 2.9.7
Causes
• Multiple engine failures;
• Incomplete performance of emergency drills;
• Flight crew actions in securing and re-starting engines;
• Drag from unfeathered propellers;
• Weight of ice;
• Poor
CRM; •
Lack of contingency plans; and •
Loss of situational awareness. 2.9.8
Safety recommendations
• The authority should remind pilots to use correct phraseology.
` •
The authority should research the most effective form of presentation of emergency reference material.
Chapter 2. Basic Safety Concepts 2-33
Safety investigation for improved system reliability
2.9.9
The facts
• An old generation two-engine turboprop commuter aircraft engaged in a regular passenger transport
operation is conducting a non-precision approach in marginal weather conditions into an uncontrolled, non-radar, remote airfield.
• The flight crew conducts a straight-in approach, instead of following the full published approach
procedure. •
Upon reaching MDA, the flight crew does not acquire visual references. •
The flight crew abandons MDA without having acquired visual references to pursue the landing. •
The aircraft crashes into terrain short of the runway. 2.9.10
Findings of the safety investigation
• The flight crew committed numerous errors and violations.
But:
• The flight crew composition, while legal, was unfavourable in view of the demanding flight conditions.
• According to company practice, the flight crew pilot made a straight-in, direct approach, which was
against regulations. •
There was a lack of standards for commuter operations in the State. •
There was a lack of supervision of air traffic facilities by the State. •
The authorities had exhibited disregard of previous safety violations by the operator. •
The State’s legislation was out of date. •
There were conflicting goals within the authority, i.e. facilitating industry development versus safety oversight needs.
• There was a lack of resources within the authority to fulfil its responsibilities.
• There was a lack of a State aviation policy to support the authority.
• There were deficiencies in the State’s training system.
2.9.11
Causes
• The flight crew’s decision to continue approach below MDA without visual contact;
• The decision was influenced by performance pressures; and
• The decision was influenced by the airline’s poor safety culture.
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2.9.12 Safety recommendations
• The report includes numerous front-line-oriented recommendations regarding flight crew performance.
• The report also contains recommendations with regard to:
— reviewing the process of granting an AOC by the authority; — reviewing the State’s training system;
— the definition of an aviation policy which provides support to the task of the aviation administration; — reforming existing aviation legislation;
— reinforcing existing legislation as an interim measure; and — improving both accident investigation and aircraft and airways inspection processes.
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