Thursday, 19 November 2015
Everyone who writes about aviation safety eventually comes around to the subject of risk management. Managing risks is not as simple as a checklist. Risk management can be done only through a deal the pilot makes with his/herself.
You can tell a kid a thousand times not to venture out on an apparently frozen pond, but in the end each individual has to come to a conclusion about what is risky, what is not, and what level of risk is acceptable.
Because bad decisions lead to accidents, a good understanding of the risks and of the fact that when improperly or recklessly done, flying can be extremely dangerous, is required. A strong sense of self-preservation is also a definite risk-management asset. No checklist will ever take the place of these things.
The risk is lowest when flying a well-maintained simple aeroplane on a clear and calm day. Beyond that, the risk increases. General aviation flying isn’t going to get any “safer”, but that doesn’t mean that each individual pilot can’t improve his or her personal safety potential.
The best way to learn about risks is to look at the mistakes other pilots have made and learn from them. These are chronicled in the accident reports issued by the CAA and others. In many cases it transpires that a pilot got to a point where even fancy footwork and a burst of brilliance could not save the day.
As kids we learn that “if at first you don’t succeed, try try try again”, but in aeroplanes the risk increases greatly when you do. Maybe the saying should be modified, to advise doing something more easily managed rather than simply to repeat that which got the better of you the first time.
One engine or two? There may be valid reasons for buying a twin rather than a single. They climb better, go faster, and carry more. But the riskiest part of twin flying comes when a pilot does something in a twin that he wouldn’t do in a single. All propeller aeroplanes are viewed as equals by things like weather and flight envelopes. A pilot is operating in a high-risk zone if this is not acknowledged.
Also, any thought about “buying” safety is a risky one. The Cirrus is an aeroplane you can buy with an airframe parachute fitted as standard. Yet the Cirrus fatal accident rate is no better than that of similar aeroplanes. That is no reflection on the aeroplane but it does say a lot about the risks that pilots take in the aeroplane.
An extremely risky moment comes when a pilot flies with this thought: “I think I can make it.” A basic high level of confidence is certainly required of a pilot, but overconfidence is not good. We need to know what we are doing and then do it well. If there is any doubt, don’t.
The final risky moment I’ll share with you applies to motorcycles, hot cars and power boats as well as aeroplanes. It comes when a person thinks or says, “Watch this!”
Thursday, 12 November 2015
(Acknowledgements: AIR FACTS/Richard Collins)
In 86% of fatal GA accidents in the USA “pilot error” is given as the cause. If only it were that simple! To use a rugby metaphor, it really starts with a “pilot fumble”. The ball is dropped, but the option is still there to recover, and the error does not actually occur until the pilot fails to do so. 10% of fatalities occurred on missed approaches or go-arounds, and as only a tiny percentage of total hours are flown while doing these procedures, they can be defined as being quite hazardous.
One more rugby metaphor: The practice of holding onto the ball with both hands when a potential hazard looms. In flying, we need a version of this, and it needs to be a pilot’s operating mode which becomes active before a time of potential stress becomes critical.
A go-around is a time for a burst of brilliance and fancy footwork, but you have to be locked, loaded and ready to deliver. There is a lot going on requiring heavy-duty pushing and shoving, which might be more apparent on a go-around than in other situations. For example, the more flap you have extended, the more aggressive you need to be.
There is also a need to think carefully about how you use the elevator trim as the manoeuvre unfolds. Elevator trim is speed-related, and an aeroplane will seek the speed for which it is trimmed. Flap retraction on a go-around, usually from full to take-off initially, will result in a pitch change. The trim for the full-flap approach speed is likely to be quite different from the trim required in the subsequent climb-out.
Better to leave the trim alone until the required changes in configuration have been made and until the airspeed is on the desired value, and then trim away the forces. Accept the increased pushing and pulling as a reminder of the difference between what the aeroplane wants to do and what you want it to do.
A pilot flying a go-around is at a disadvantage because, unless it is prompted by some conflict with other traffic, he or she has usually already messed up! Key indications were ignored, bad decisions were made, and the airplane was flown into a difficult situation.
A go-around is unlike a take-off, in that it usually starts with full flap and with the pitch trim set for a full-flap approach. Thus the aeroplane will be out of trim, and the reduction in flap will induce what feels like a sinking spell requiring a substantial change in pitch attitude with a correspondingly high stick force. After making the errors that got the aeroplane to such a bad place some pilots may exhibit a reluctance to be aggressive with the power and the controls, but this is a time for decisive action.
Some pilots may also like to maintain a nose-up trim throughout the landing process as they feel it keeps the pitch forces low, but pilots so doing could find themselves at a disadvantage should the landing have to be aborted.
Go-arounds, not only “touch-and-gos”, should thus get plenty of attention in both initial and refresher training.
Friday, 6 November 2015
A stall is likely when an aircraft’s angle of attack is greater than the critical angle of attack without any compensatory power setting. To safely avoid and recover from a stall and possible subsequently fatal spin:
- Be alert and prepared at all times to face the unexpected
- Keep your wings and airframe clean and clear of ice, anticipate bad weather and stay in Visual Meteorological Conditions (VMC)
- Keep a safe margin from the stall angle of attack by keeping always a safe speed. When manoeuvring, the load factor and the stall speed increase, so keep the speed up!
- Apply immediate recovery action whenever the stall warning sounds or if the aeroplane does not normally react to your control inputs
- Relax any back pressure on the control column or move it forward centrally to reduce the angle of attack. In a turn, beware not to induce yaw by roll while moving the column to the centre
- Be gentle on the stick or wheel to avoid secondary stall or spin
- Apply power with care so that resultant forces do not make the situation worse.
- Read, understand and remember the contents of the Aircraft Flight Manual and Pilot Operating Handbook for your aeroplane
- Remember the stall indicated airspeeds for the different flap settings
- Recognise the stall warning indications for your aeroplane and maintain your handling skills by practising your stall avoidance and recovery procedures regularly at a safe altitude – preferably with an instructor
- Seek advice from an instructor if you are unsure of any technique
- Know the behaviour and feel of your aircraft at a high AoA, so that you can use this behaviour and feel to detect when you are close to stall