Human Factors Incident Reporting — Page 310, Lesson 509

I want to walk you through a topic that is absolutely central to aviation safety — Human Factors Incident Reporting. This is where we stop talking about theory in the abstract and start looking at real events that have happened, reported through a system called CHIRP. CHIRP stands for the Confidential Human Factors Incident Reporting Programme. It's a voluntary, confidential system that lets pilots and other aviation professionals report safety concerns without fear of punishment. The goal is to learn from mistakes and design better cockpits, better procedures, and better training. Let's start with CHIRP Report 3, which is about cockpit design. The pilot in this report describes a situation where he set the QFE — that's the barometric pressure setting that makes the altimeter read zero at the airfield elevation — and then started a descent to 2000 feet QFE. When he reached 2000 feet, his co-pilot said "You've gone below 2000 feet." The pilot replied that he had not, but then looked at his altimeter and saw that it was set to 1030 millibars, not the correct QFE of 1020 millibars. That's a ten millibar error, which corresponds to roughly 280 feet of altitude error — enough to put you below your cleared altitude. Now, the report asks us to consider Figure 16.1, which is drawn to actual size. The altimeters are viewed from a distance of about 50 centimetres, and the instrument panel suffers from shake — vibration. The individual helicopters in this fleet are fitted with altimeters of types A and C, or B and C. Because pilots fly from either seat, a pilot may find himself using an instrument of any type on any given flight. The reporter says that most of his colleagues have difficulty in seeing and setting the correct pressure settings. So the core issue here is that the altimeter control knobs and displays are not standardised across the fleet, and the design makes it hard to read and set the correct barometric pressure, especially under vibration and at a normal viewing distance. This is a classic human factors problem: the equipment does not accommodate the human's perceptual and motor limitations. Now let's move to CHIRP Report 4, which is about status and role. This is a very sobering report. The aircraft was a twin-propeller commuter aircraft. The captain was also a senior manager in the airline and known to be somewhat irascible — easily angered. The first officer was junior in the company and still in his probation period. It was the end of a long day, and the captain was plainly annoyed when company operations asked for a further flight, but he reluctantly undertook it. During the approach at the end of this leg, the first officer went through the approach checks but received no response at all from the captain. Rather than question or challenge the captain, the first officer sat tight and let the captain get on with it. The aircraft flew into the ground short of the runway because the first officer did nothing to intervene. It transpired that the captain had failed to respond to the checks not because he was in a bad mood but because he had died during the approach. This report illustrates a critical human factors concept: the power gradient between crew members. The first officer's junior status, the captain's senior management role and irascible personality, and the first officer being on probation all created a steep authority gradient. The first officer was unwilling to challenge or question the captain, even when the captain was not responding to standard checklist calls. The tragic outcome was that the captain had actually died — a medical incapacitation — and the first officer's deference prevented him from recognising the emergency and taking control. This is a powerful lesson about the importance of assertiveness, crew resource management, and flattening the authority gradient so that any crew member can speak up regardless of rank. Finally, let's look at CHIRP Report 5, which is about risky shift. This is a phenomenon where a group makes more extreme decisions than any individual would make alone. The report describes a situation after about two weeks of IMC — Instrument Meteorological Conditions, meaning flying solely by reference to instruments — in an Aberdeen winter. Both pilots, the co-pilot and the captain, were gripped by an overwhelming desire to SEE something other than white mist. Between oil rigs, with the cloud base at destination known to be 200 feet, they had no problem — but they were still in IMC at the time. The captain tells the first officer to set the Radar Altimeter bug at 100 feet — that's the altitude warning bug on the radio altimeter — and set the radar to the 5-mile range scale and tell him if any hard bits show up. The captain then starts a descent to regain VMC — Visual Meteorological Conditions. Still no sign of the sea at 200 feet. He keeps going down slowly. The radar screen is still clear. He keeps descending, well below limits, but has to actually get to SEE again, and after all this is the North Sea where men are men, etc etc. They actually level out at 75 feet, but still in IMC — but can see the waves below. The reporter says "No problem as you never come across 75 ft waves." The Decca navigation system is playing up, and the pilot becomes engrossed in a navigation problem, radio calls, and an intermittent engine "ANTI-ICE" caption. This report shows how the desire to see outside — a psychological need after prolonged instrument flying — can override standard operating procedures and minimum altitudes. The pilots descended well below the published minima, to 75 feet, still in cloud, over the sea. They rationalised the risk with phrases like "this is the North Sea where men are men" — that's the risky shift, where the group culture normalises dangerous behaviour. They also experienced task fixation: the pilot became engrossed in the navigation problem and other tasks while flying at an extremely low altitude in instrument conditions. This is a textbook example of how human factors like motivation, group norms, and task saturation can lead to a breakdown in safe operations.