Practical Actions


We have compiled some relevant information below. There are links to full articles and GAPs here too, and you will find more information on the CAA website.


Light-Commercial Ops

twin night tarmac bannerRegardless of whether you’re a pilot, an engineer, or the CEO, you should be constantly reviewing the way you do things and trying to make improvements. It is only through having a proactive and open management structure that a safe operating environment can be created. Everyone should be actively taking part in the company’s safety programme and communicating information and new ideas freely.

Operational Pressures

Today’s aviation environment is very competitive, and operators may find it difficult to turn down business that they feel their competitors might accept. But the reality is that ‘pushing the limits’ may result in an accident that exacts a large financial toll on a business (even to the extent of destroying it). And in the process, it is likely to damage reputation, possibly cost lives, and cause great emotional upset.


A sound company safety culture, thorough pilot and engineer training, and the adherence to well-documented company procedures are a must if an operation is to be safe.

Safety Culture

The culture is set from the top. If senior management places a clear importance on their safety culture being a good and just culture, the rest will follow. It’s about being explicit about how you do things in your organisation – the safe way.

Complex Systems

A common theme that emerges from accident investigations in this category is that of pilot unfamiliarity with the aircraft systems and performance characteristics – especially fuel management and weight and balance.

Type Ratings

Type ratings can be expensive, and some operators may be tempted to keep the number of hours flown to a minimum to save money. Ironically, light commercial operations are the very area that comprehensive type-rating training is most needed, and inadequate type-rating training has been a significant factor in a number of New Zealand accidents.

Pilot Competency Checks

The Flight Crew Competency Check and BFR not only allow a pilot to prove that they are competent to safely handle the aircraft within the company’s particular operating environment, but are also an opportunity to learn more from an experienced pilot. It is important that these checks are treated as a chance to discuss problems and to learn new ways of doing things, rather than being viewed as a test.

Pilot Experience Levels

preflightLight commercial operations are often a stepping stone for pilots on their way to an airline job. Because of this, some pilots do not tend to remain with an operator for very long. Lack of experience in an organisation can therefore become a problem. This not only becomes apparent in day-to-day operations, but also when training and supervising new pilots. Without this depth of experience within a company, new pilots may not learn all they need to. While many operators set relatively high ‘total time’ requirements for new positions, such experience has often not been gained on the larger and more complex aircraft for which a position is sought. The cycle can be self-perpetuating, meaning that pilot experience levels diminish to the point where safety may be compromised.

Pilot Pressure

Because profit margins are often slim, operators are sometimes under pressure to fly as many hours as possible to avoid cash flow problems. Pilots are aware of this and may feel they will be penalised if they ‘don’t get the job done’ and worry about keeping their job. The concept that ‘we want you to get the job done – but safely’ should be the norm.

Many pilots want to log flying hours towards an airline career as quickly as possible and may feel under pressure to fly as often as they can.

Pilot Decision-making

Learning to assess a situation and make a safe decision about whether or not to do (or continue) a flight is a skill that comes with experience and good pilot decision-making training. It is important that such training is provided for new pilots and that experienced pilots are always on hand to provide valuable guidance and support when needed.

Aircraft Maintenance

If your aircraft develops a defect, you should be careful not to put your maintenance organisation under pressure to get it fixed in an unreasonable length of time –maintenance errors can occur when people are put under pressure.

If your aircraft does develop a non-deferrable defect that can’t be fixed at short notice, do not be tempted to operate with it – it’s dangerous and illegal. An aircraft that is flown with defects is definitely a sign of a poor operation. Most passengers would not be impressed if they knew that the aircraft they are about to get in to is not 100 percent airworthy.


Only you can tell if you are fatigued. It is irresponsible to turn up to fly while you are fatigued, and your responsibility is to try to ensure that you are well rested before flight.

If you are fatigued, then you shouldn’t fly and you need to tell the employer you are unfit to fly. Don’t expect them to take it well if you were out late the night before, but if it’s out of your control, you need to be honest about it.

Full Vector article on light commercial operations here.

Additional Vector article on getting your first commercial job here.

Further Vector article on pilot decision making here.


Carbon Monoxide


Image courtesy of

Carbon monoxide (CO) is a by-product of combustion in engines. The process of combustion combines oxygen from the air with fuel to produce carbon dioxide (CO2) and water (H2O). If the combustion is incomplete, or if there is a shortage of oxygen in the burning mixture, then sometimes instead of forming carbon dioxide, the result is an increase in the levels of carbon monoxide (CO).

The key difference between carbon monoxide and carbon dioxide is their effect on our bodies.

Carbon dioxide (CO2) is a natural part of the respiratory cycle, and it is constantly being exchanged for oxygen in our blood.

Carbon monoxide (CO) is a much more reactive molecule, and has a far greater affinity for haemoglobin in the blood. Rather than being easily exchanged for oxygen in the lungs, it tends to stick to the haemoglobin, and this prevents the blood picking up oxygen. This lack of oxygen has basically the same effect as hypoxia – that of being at too high an altitude.

Unlike lack of oxygen due to being at high altitude, CO poisoning cannot be fixed quickly or simply by descending to thicker air, or by taking some breaths of oxygen. Because of the affinity of the CO molecule for haemoglobin, it takes up to several hours for the body to replace the CO in the blood with oxygen.

CO is tasteless and odourless, which adds to the danger it poses to pilots. Where CO poisoning has occurred through a fault in the exhaust system, it is possible to detect other smells from exhaust gases, but the CO itself is undetectable by human senses alone.

Carbon Monoxide Detectors

All piston engine aircraft, where there is a possibility of exhaust gas reaching the cockpit, should be fitted with a CO detector. Pilots should check the detector as part of the preflight. The check should include colour and expiry date for the spot type detectors, or a system and battery check for the alarm type.

Pre-flight and In-flight Precautions

The preflight check should always include a careful examination of the exhaust system and any heating ducts that the aircraft uses. Cracks in the exhaust pipes, or perished ducting, can increase the potential for CO to enter the cockpit.

A regular check of the CO detector should be part of your activity cycle in flight. It would pay to be particularly vigilant if using the cabin heating.

Suspected CO Poisoning

Firstly, try to isolate the source of the CO. If cabin heat is selected on, turn it off. Ventilate the cabin with as much fresh air as you can. If you are fortunate enough to have oxygen available, use it. Changing power setting, mixture setting, aircraft configuration, or speed may all change airflow and CO levels in the cabin.

Check yourself for symptoms. Check your vision. Advanced CO poisoning may show up by a change in your skin colour – maybe your fingernails have turned bluish (but be careful not to confuse temperature effects, for example, cold fingers, for CO exposure).

Let someone know of your predicament. A PAN or MAYDAY call to ATC may be in order. They may be able to help you to the nearest suitable landing place, or monitor your flight path.

Remember that the effects of CO take a considerable time to clear. A couple of breaths of fresh air might make you feel better, but the effect of the CO on your cognitive ability and motor skills may take some time to disperse. For that reason, it will generally be advisable to land as soon as you can.

Full Carbon Monoxide article here.


Assertiveness in the Aviation Workplace


Being assertive is not easy. It’s often easier to be aggressive or passive. So how does someone without natural assertiveness learn the skill? And why is it important for aviation safety?

Organisation development specialist, Julie Rowlands, says that if people want to develop assertiveness, they do have to screw up a bit of pluck.

“It’s the courage to do what you know is right, in the face of being challenged about it. Or, when someone is testing you, and you don’t like their style, and you don’t like the impact they’re having on you, it’s having the confidence to do something constructive about that.”

Julie says men, in particular, confuse assertiveness and aggressiveness. Being the loudest voice in the room, controlling the group, and staring down people who disagree with you, is not being assertive – it’s being aggressive. And while organisational goals may still be reached by someone ‘monstering’ their staff in such ways, morale will inevitably be low, output poor and staff churn high.

So what is ‘being assertive’?

“What underpins assertiveness is the acceptance that everyone in an employment situation has rights,” says Julie Rowlands.

“A manager has the right to expect a certain level of behaviour and/or performance from those reporting to them. And an employee has the right to be able to offer suggestions if something is concerning them, without fear of ridicule or retribution – a ‘just culture’.”

Julie Rowlands says in some workplace environments, managers do not welcome suggestions which they automatically regard as criticism, and if from less experienced staff, invalid.

She advises employees in that environment to prepare themselves for defensiveness and attack.

“Anticipate it, and recognise that it’s normal, particularly if you have criticised someone else’s actions and behaviour. Then prepare to calmly reassert yourself again. And again. Sometimes it can take up to five ‘assertions’ to get your point of view seriously considered.”

But as Julie observes, the aviation industry is very hierarchical. “At times, it will be more difficult for the young engineer or pilot to challenge what they believe is unsafe or inappropriate.”

“It’s easy to say to them, ‘You just have to say something because safety is at risk’, but we’re not the person who has to live with the consequences of that action. It’s something they themselves have to decide to do.

“If they do decide to challenge it, however, they have to do it assertively, which means raising the issue in a way that’s often focused on a solution, rather than the problem. So instead of saying, ‘you shouldn’t be doing this, it’s wrong’ the words need to be something like ‘I’m genuinely concerned about this because of these reasons, but if you were willing to look at doing it this way, I think it might get a better outcome and a safer outcome.’

“In the face of a reasonably difficult CEO, who is short on time, something like that needs preparation so you can approach it in a composed way.”

But what about the situation where there is no time for such preparation – where someone is being asked to do something immediately, like sign off on a task they’ve had nothing to do with, and are possibly unhappy about?

“In that situation, it’s still being assertive,” says Julie, “to hit the ‘pause’ button, keep breathing calmly and ask for more information and more time to consider the request.”

Julie Rowlands says a trawl around the internet will uncover the many assertiveness courses, ‘courageous conversations’ workshops, and conflict resolution coaching now available.

Full article on assertiveness here.



windscreen ice2

Icing Prediction

It is a fairly good bet that most weather systems and conveyor belt flows contain conditions conducive to icing, but the right conditions for icing can be quite localised, and therefore, hard to predict. Where cumuliform clouds are involved, the lifetime of a cell-producing conditions conducive to icing may be measured in tens of minutes, so icing may be limited to temporary periods.

Stratiform clouds tend to persist for longer periods and can be more spread out, but the icing layer may be quite thin.

Knowing the Outside Air Temperature (OAT) and having a detailed knowledge of the weather are the best cues for predicting icing conditions. However, sometimes the only way of knowing where the icing is, is to encounter it – or to hear from someone else who has.

Induction System Icing

Induction icing is a comprehensive term which includes all types of fuel metering and all parts of the induction system where ice can accumulate. This includes the air filter, bends in the system, and critical areas of the fuel metering device, like the throttle plate in a float-type carburettor.

Impact icing forms on the surface of the air intakes, air filter, and possibly in the bends in the system, creating disturbances in the airflow and gradually closing off the air intake.

Visible airframe ice should immediately alert you to the danger of a similar build-up in the induction system. In aircraft that have fuel-injection systems, this may be the only indication of induction system icing.

Refrigeration icing forms in a float-type carburettor as a result of fuel vaporisation and low pressure, when the relative humidity is more than 50 percent, and in air temperatures anywhere up to 35°C.


For aircraft with fixed-pitch propellers, a gradual loss of rpm and airspeed are early warning signs – exactly as if the throttle was being closed very slowly. If left unheeded, the next warning will be a rough-running engine combined with severe power loss, and finally a complete power loss.

For aircraft with fixed-pitch propellers, in the early stages, the propeller governor will maintain a constant engine rpm despite the loss of power. The first positive signs will be decreasing airspeed coupled with falling manifold pressure, but these symptoms come on gradually and insidiously, and may go unnoticed. Eventually other symptoms will be experienced, such as rough running and rpm loss.


At the first indication of a reduction in rpm/manifold pressure/airspeed or height, full carburettor heat should be applied for at least 30 seconds and the mixture leaned slightly to correct the over-rich situation. A gradual return of airspeed (and engine rpm with fixed-pitch propellers) will indicate that ice had been present.

Airframe Icing

wing icing NASA2

Photo courtesy of NASA

Although ice can build up on all aeroplane surfaces, aerofoil icing (the mainplane and the tailplane) is of significant concern. Ice destroys the smooth flow of air over the aerofoil, diminishing its ability to generate lift. It increases drag, increases the aircraft weight, and degrades the control authority of the pilot. As power is added to compensate for the additional drag, and the aircraft nose is raised to maintain altitude (increasing the angle of attack), additional ice will accumulate on the underside of the aerofoils and fuselage.

Ice accumulation (on the leading edges or upper aerofoil surfaces) no thicker than a piece of coarse sandpaper can reduce lift by as much as 30 percent and increase drag by as much as 40 percent.

One particular hazard of severe icing is the tailplane, or empennage stall. Sharp-edged surfaces are more susceptible to collecting ice than large blunt ones. For this reason, the tailplane will begin accumulating ice before the wings, and at a faster rate. Because you cannot see the tailplane, you may be unaware of the situation until a stall occurs when the critical angle of attack is exceeded (this can occur at a relatively high airspeed).

Since the tailplane provides a balancing nose-up force, when it stalls, the aeroplane will pitch nose down, sometimes uncontrollably. Application of flaps can initiate or aggravate this process. Caution should be used when applying flaps during an approach if there is the possibility of tailplane icing.

Loss of thrust or lift due to ice build-ups on the propellers, rotor blades, or around engine intakes is also a serious consideration. Not only will ice accretion significantly reduce the amount of thrust or lift produced, it is also likely to cause the propeller or rotor to become unbalanced.

The blockage of pitot intakes and static vents by ice will produce pressure instrument errors. The best defence against pitot icing is to ensure that the heating elements are working during the pre-flight, and are switched on well in advance of any anticipated icing conditions.


ice rivetsFrost forms on aircraft when the OAT falls below 0°C and there is visible moisture in the air – usually while on the ground overnight.

Frost does not have the same weight penalties as other icing, but it does roughen the smooth surface and disrupt the airflow over the wing. This can lead to flow separation and significantly reduced takeoff performance. It is essential to ensure that the wings, tailplane, and windscreens are cleared of ice before flight. Frost can be carefully brushed or washed off the aircraft, but be careful not to scratch surfaces or provide more water that can refreeze later!

Frost can also form in flight. It usually occurs when the aircraft has spent long enough in temperatures below 0°C to have ‘cold soaked’ to that temperature and then encounters moist air. This can occur after takeoff on a winter’s morning, or when an aircraft descends into warm moist air. This can also happen to VFR aircraft in clear air.


Remove all ice or frost on any lifting surface before flight. Your Aircraft Flight Manual or company Standard Operating Procedures will have guidance on how best to achieve this.

Avoid icing conditions if you can. The freezing level in ARFORs and SIGMET warnings will alert you to the areas you are most likely to find ice, and if you can’t avoid these, then limit your exposure and don’t rely on the de-icing capability of your aircraft to cover all situations. No aircraft are certified for flight into severe icing conditions, and if you encounter them, you must get out as soon as possible.

Know how your particular de-icing or anti-icing system works. There are a number of different methods used, so know when and how to use yours. If you fly a variety of types, make sure you know the differences.

Roll Upsets

Roll upsets due to airframe icing are a serious control problem, which can be fatal. They occur for a number of reasons:

Ice build-ups on the wing lower surface and fuselage eventually causing a conventional stall as the angle of attack is progressively increased, which is followed by a roll upset.

Under certain conditions, ice can form in ridges just forward of the ailerons, disturbing the airflow over them in such a way as to create an aerodynamic imbalance. Eventually the aileron will ‘snatch’ or deflect out of the neutral position of its own accord and cause the aircraft to roll. This can happen at angles of attack that may be considerably less than the stalling angle. On unpowered controls, it is felt as a change in control-column force. Instead of requiring a force to deflect the aileron, force is required to return the aileron to the neutral position. Aileron instability sensed as an oscillation, vibration or buffeting in the control column is another clue that the airflow over the ailerons is disturbed.

Loss of roll effectiveness can result when ice forms ahead of the ailerons and disrupts the airflow over them in such a way that it reduces their effectiveness to the point where roll performance is less than desirable. This is different from the aileron ‘snatching’ scenario, where aerodynamic balance is disrupted but effectiveness is essentially maintained.

A further condition that can contribute to roll control problems is the accumulation of more ice at the wings tips than the roots. This occurs because the wings tips are thinner, may have a different camber and a shorter chord, and often have a degree of aerodynamic washout relative to their roots. For these reasons, the wing tips will tend to accumulate ice quicker, thicker and further aft than on a general purpose aerofoil. Such ice build-ups cause separation of the airflow at the wing tips, which compromises aileron effectiveness.

Aircraft Icing Certification Levels

Icing conditions and their effects on aircraft aerodynamics are not yet completely understood so pilots must not be over reliant on de-icing and anti-icing equipment fitted aboard aircraft that have been certified for flight into icing conditions. Severe icing conditions will most likely be outside the aircraft certification-icing envelope.


PIREPThe best way to warn other pilots about actual icing conditions is to broadcast a PIREP (pilot’s report).

This serves the dual purpose of warning other pilots and alerting ATC to the problem. ATC can then assist by giving you routing or altitude changes that can facilitate clearing the icing conditions as soon as practicable. The same service can then be provided to other aircraft to help them avoid the area of known icing. PIREPs help aircraft operators and aviation authorities form a picture of where icing is most likely to occur, which is something that the whole industry can benefit from.

PIREPs are also passed on to MetService, who will use the information to update weather forecasts, and if necessary issue SIGMETs. Any information pilots can supply about icing they have encountered also serves, over a period of time, to improve the ability of MetService to predict icing conditions more accurately.

For detailed information refer to the Aircraft Icing Handbook, at the bottom of this page, or go to the NASA website where they have two online courses, one on ground icing, the other on in-flight icing.

Full Vector articles; Ice, Icing, Airframe Icing, Carburettor Icing and More on Icing.

See Vector article on PIREPs here.