Loss of Control Review

Over the past 5 years more than 60% of RAAus fatal accidents are believed to have occurred due to loss of control events, but what do we mean when we talk about loss of control, and what are the most common scenarios resulting in a loss of control event?
 

At RAAus, we typically refer to two forms of loss of control events:

  • Loss of control in flight (LOC-I), and;
  • Runway loss of control

Loss of control in flight events refer to occurrences where the aircraft operates outside of the normal flight envelope, or when normal control of the aircraft is lost during flight. These often result from failure to prevent or recover from a stall and/or upset. This may refer to occurrences immediately after take-off, during the final approach to land or flare, or during any other phase of flight. Unfortunately, loss of control events are the number one cause of fatal accident within RAAus operations, as well as within light aircraft operations globally.

The most common cause of loss of control in flight is stall/spin events. Another form of loss of control event is a spiral dive often from VFR flight into IMC (covered in National Safety Month week 1 content).


Runway loss of control
refers to occurrences where directional control of the aircraft is lost, often resulting in a ground loop of runway excursion. Runway loss of control is one of the most common causes of aircraft damage, however typically results in minor injuries.

 

Loss of control in flight occurrences

Loss of control is a very broad category of occurrence which may occur during many different scenarios – The most common similarity between these occurrences is often the failure to identify and prevent a stall. 

These occurrences may occur to any pilot at any stage in their flying – Over the past 5 years we have seen fatal loss of control events across a range of experience levels from only 30 hours through to many thousands of hours.

So let’s take a look at some of the most common scenarios:


Loss of control after take-off

Loss of control after take-off may occur due to a number of different reasons. The first of these is due to the failure to conduct appropriate performance calculations. This may result in failure to climb after take-off leaving the pilot unable to clear obstacles at the end of the runway or insufficient runway available for the take-off. During this situation pilots may pull back on the control in an attempt to clear obstacles resulting in a stall spin event.

Another cause of loss of control after take-off is when the aircraft encounters an upset due to environmental conditions or is distracted, allowing the aircraft to get too slow during the climb out or turn onto cross-wind. Failure to identify and prevent a stall during this phase of flight often results in insufficient altitude to recover.

Loss of control following engine failure

One common cause of loss of control event is following an engine failure. This is particularly important during an engine failure after take-off, where the aircraft is established in the climb. When an engine fails during this phase of flight, the pilot has very little time available to immediately lower the nose, establish and maintain best glide speed. Failure to act immediately following an engine failure after take-off is likely to result in a stall with insufficient altitude to recover.

Loss of control in the turn

Loss of control events commonly occur in the turn due to the increase in stall speed with the increase of angle of bank. One scenario where this may be emphasised is during the base to final turn where a pilot overshoots the centreline. The tendency in this scenario is to increase the angle of bank and apply more rudder to regain centreline, however in doing so, the result is an uncoordinated high angle of bank turn at low speed which often leads to a spin.

It is highly important that pilots recognise the increase in stall speed in the turn and avoid high angle turns at low airspeed and/or low altitude.

The following table shows the increase in stall speed with an increase in load factor. Assuming a 40kt stall speed, if the pilot enters a 60deg turn, the stall speed is now 56kts.

Angle of Bank

Load Factor

% increase in stall speed

New stall speed

0

1

 0

50

45

1.4

20

60

60

2

40

70

75

4

100

100

 

 

 

 

 

 

 

 

 

One common area of concern in relation to loss of control events in the turn is in relation to mustering or farm flying operations. During these flights pilots may still operate above 500ft AGL monitoring stock, fences or troughs. With the pilot focusing on a point outside the aircraft it is easy to become distracted in the turn failing to identify a reduction in airspeed. It may also be that the pilot is actively creating an unbalanced turn by applying cross controls to maintain the turn but lift the wing for improved visibility, inducing a spin scenario. Training for operations at 500’AGL and below is available, however all pilots would benefit from completing training to ensure the aircraft remains balanced and at a safe operational speed no matter what height flight is being conducted.

Loss of control in the go-around

The go around is another common scenario in which loss of control events occur. These occurrences often occur due to a late decision to conduct a go-around when the pilot is attempting to quickly regain a climb. The tendency here is to apply full power and pitch the nose to achieve a climb attitude, this may be further complicated by the trim setting for landing and raising the flaps on the aircraft resulting in an increased stall speed as well as not controlling yaw due to the increased power input.

It is important that pilots regularly practise go-arounds remembering that the first phase is to achieve level flight to increase airspeed, then to commence a climb. Pilots should also make sure they consider an early decision to commence a go-around rather than leaving this to the last possible opportunity. Often pilots only conduct a go-around once controlled flight is departed during the flare, making a difficult situation even harder.
 

VFR into IMC

1 in 10 fatal accidents occur due to VFR flight into IMC. Most of these events result in a loss of control due to pilot disorientation. This topic was covered in week 1 of National Safety Month.

 

Tips to avoid loss of control events:

  1. Airspeed
    Pilots should always operate while attempting to fly accurate airspeeds relating to their aircraft type. If operating in gusty or thermal conditions, add a buffer of 5kts to climb-out or approach speeds to offer an additional margin of safety.
  2. Rudder
    Spin events occur due to unbalanced flight – Pilots should pay extra attention to ensuring they fly accurately with the balance ball centred during all phases of flight.
  3. Stall recognition and recovery
    Do you know the signs of a stall? When was the last time you practised stalling? Stall recognition and recovery is the best method of avoiding loss of control events. If you feel like you may be a little rusty, why not contact your local instructor to practise stalls?
  4. Altitude
    There is a common saying that the three most useless things in aviation are: Altitude above you, runway behind you, and fuel not in your tanks. Low altitude flying requires additional training to equip pilots with the relevant skills for safe conduct. This also applies to farm flying which, although may be carried out above 500ft AGL, is still not suitable for recovery from a stall/spin. Avoid scenarios where you may be operating low and slow with nowhere to go!
  5. Performance
    Pilots must always consider performance calculations relevant to their aircraft. Although many light aircraft may not have full performance charts and take-off and landing charts, it is important that pilots consider the effects of weight, density altitude, and runway surface prior to each take-off and landing and always use full available runway length, even when you know sufficient length is available.
  6. Distractions
    Pilots must continue to manage distractions during all phases of flight, however this is particularly relevant a low altitudes. Try implementing a sterile cockpit system where you ask passengers to remain quiet below 1000ft AGL, avoid the temptation to reach for you mobile phone, and be particularly cautious of becoming fixated on a point outside of the cockpit below 1000ft AGL, such as farm spotting, or circling your friend's house!
  7. Emergency drills
    Pilots should brief themselves on the actions in the event of an emergency prior to each and every flight. This includes the actions in the event of an engine failure after take-off, during which the first action must be to lower the nose. Pilots should regularly practise stalls and forced landings or engage an instructor to improve your knowledge and abilities.