Failure To Follow Procedures

Failure to follow procedure can lead to incidents and accidents related to both flight operations and maintenance procedures. In aviation it is very important that procedures are adhere accurately and constantly by pilots, ground crews, engineers and even cabin crews. These procedures are written to ensure that proper operation is conducted, thus guiding error proned human being from doing the wrong steps. However, over time people get use to the step and tend to skip procedures or purely conduct operation by the weakness of human memories.

The Dirty Dozen in Aviation

These are the identified common factors that lead to human mistake in aviation and other industry. Humna being is has a lot of weakness by nature, and it is impartant that aviation manager and human factor practitioner understand these weakness to implement correct measure to reduce this errors. Dirty dozen is a toll use to bring down the case study into specific human factor and could then be analysis on the factors for discrepencies thus improving the system. Moreover, human factors awareness can lead to improved quality, an environment that ensures continuing worker and aircraft safety, and a more involved and responsible work force.FAA[3]

The Dirty Dozen are:
1) Lack of Teamwork
2) Fatigue
3) Lack of Resources
4) Pressure
5) Lack of Assertiveness
6) Stress
7) Lack of Awareness
8) Norms
9) Complacency
10) Lack of Knowledge
11) Distraction
12) Lack of Communication

According to the Civil Aviation Authority, on average, a helicopter takes off and crashes with no one board once a year in New Zealand. The following reports exemplifying failure to follow procedures were retrieved from CAA Occurrence Briefs [1]

Accident Briefs

Registration : ZK-HPR
Aircraft Model : Robinson R44
Date and Time : 21 Dec 08 at 14:00
Location : Rangitata Island
Nature of Flight: AGRICULTURAL
POB : 0
Injuries : nil
Damage : Substantial

The pilot vacated the aircraft leaving the controls unattended in order to discuss the job with the landowner. The helicopter became airborne and rotated 180 degrees before landing on its skids, damaging the main rotor blades and tail boom. The aircraft flight manual contains a caution to never leave the helicopter flight controls unattended while the engine is running.

(Image embedded from Fillmore Gazette on 03 Sep 2009)


There are several reasons for a pilot to leave a helicopter while it is running:

  • Escort passengers to and from the machine safely (if there are no ground staff available)
  • To accomplish quick task (load/unload stuffs/refuel)
  • Speak to the person they are working for about the job (agricultural pilots to farmer)
  • Other extenuating circumstances such as the risk of the weather changing quickly and not being able to start the helicopter again in such a hostile environment

Pilots leave their helicopters running primarily to save time. Many believe it can be done safely, and after doing it for years with no consequences it becomes a habit. Complacency pushes aside the very real possibility of the helicopter taking off without them.

How Does it Happen?

When a helicopter is on the ground a friction lock, and/or similar device, is applied to the collective to stop it being raised. If the friction lock is faulty,and the collective vibrates up, it will increase the pitch on the blades. The governor will then increase the power by a corresponding amount. If there is enough weight in the helicopter, this in itself would not be enough for it to become airborne, but sometimes the reduction in weight from the pilot getting out can mean there is just enough power applied to get the helicopter airborne.

A friction lock is also applied to the cyclic. If this fails the rotor disk will flop around. The yaw pedals also have the potential to creep or be bumped by a passenger. This can lead to the helicopter rotating on the ground and more than likely rolling over as a result. (Source: Vector) [2]

(Image embedded from Bush-Planes on 03 Sep 2009)


Lessons Learned

Pilots and operators should have strict safety procedures for leaving a helicopter unattended. These should cover the positioning of locks and frictions, RPM, limitations on wind direction and strength, instructions to be given to passengers who are left in the helicopter, the centre of gravity position and the effect on this when a pilot disembarks, and the distance a pilot is allowed to be away from the aircraft. The helicopter should be in continuous view of the pilot, there should be no extraneous people in the area who could walk into it, and dual controls should not to be fitted in front of a passenger. (Source: Vector) [2]

Remember – uncommanded fly-aways do happen, and you are taking a calculated risk every time you decide to leave a helicopter when it is running.

1. CAA Occurrence Briefs Retrieved on 01 Sep 2009
2. Vector Retrieved on 2 Sep 2009
3. FAA Retrieved on 15 Aug 2012

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