5-M Model Approach To Accident Investigation


The 5-M Model comprises of Man, Machine, Medium, Mission and Management are five core areas that failing factors of accident/incident may appeared in. This model is one of the most common used method in aviation industry to examine aviation accident/incident. It provide manager with a systematic way of focusing and analysing areas that errors mostly occurred within the structure of organisation.

Picture embedded from SafetyForum on 26 Sep 09

Breakdown of 5-M Model [1]

5-M Factors
Man Refers to human elements inclusive of Physiological, Psychological, Proficiency aspects as well as Qualifications of performing tasks
Medium Refers to the environment where the task is to be conducted inclusive of Weather conditions, Terrain, Obstructions, Sunset/sunrise, Airfield lightnings, Navaids available
Machine Refers to the Design, Manufacture, Maintenance of aircraft and Engineering reliabilty/ Performance of equipment
Management Refers to supervisory capacity of management in terms of Regulations, Polices, Attitudes towards safety
Mission Refers to the type of task implemented, whether it was Complex or Routine


When an aircraft accident occurs many questions are asked regarding the human component that was operating the aircraft or system at the time of the accident. Successful accident investigation therefore requires the investigator to probe beyond the,'human failure',so as to be able to determine the underlying factors that contributed or lead to this failure. The question 'Why', arises a lot during investigation of the operator at the time of investigation.

For example4;

  • Was the individual mentally or physically capable of responding properly? If not, why?
  • Did this failure occur due to a self induce state such as alcohol intoxication or fatigue?
  • Had the individual been properly trained in how to cope with the situation that lead to the accident?
  • If not who was responsible for the training deficiency and why?
  • Was the individual given adequate operational information on which to base decisions?
  • If they were not given proper information, who failed to provide the information and why?
  • Was the individual distracted to the point that he/she was not paying proper attention to their duties?
  • If so who or what created the distraction and why?

These are only a few of the questions that arise during a human-factor investigation when trying to establish what caused the accident. The answers to each of such questions are very vital for the effective measures to be put in place so as to prevent the accident from


Due to technology, the machine (aviation technology) has enabled great advances to the aviation industry. Through automation, human mental work load has been reduced significantly and productivity increased3. However when machine and computer become more complicated and advances to replace more jobs from human, it surface occasional problems which are detected with relation to human limitation in handling them. For example, the design, maintenance and manufacture of the aircraft. Therefore, modern aircraft designs are revise through these problem detected to further reduce the effect of any of these hazards. For instance good design should not only seek to make system failure unlikely, but it should also ensure that, should it never the less occur, one single failure will not result in an accident4.


The medium(environment) in which the aircraft operation takes place, equipment is used and personnel work directly affects safety4. From the point of view of accident prevention the environment is considered to comprise of;
The natural environment.
The artificial environment.
One example could be the unexpected weather condition that form ice near the engine area where ice is injected into the engine, or reduces the air intake amount which resulted in engine failure.


The type of mission or the purpose of the operation is also considered important during the investigation process. This is because each risk is associated with different types of operation which do vary. One example is the mission/procedure too ambitious that could not be possibly achieve? Each mission being different will have certain intrinsic hazards that are accepted with the type of mission4.


The training of proper safety procedures is normally done by the management team of the certain airline or aviation organization. Therefore accident prevention rests on management,as its only management in any organization that controls the allocation of resources4. For example it is management that determines the type of aircraft to purchase, what routes to operate in, training and operational procedures to be given,personnel who will maintain as well as fly the aircraft and so forth. Management are thus the cornerstone for safety and accident prevention techniques.

Case Study of SQ 006

Singapore006.jpeg 0111crash-plane.jpg
Picture embedded from AirSafety on 8 Oct 09 Picture embedded from ChannelNewsAsia on 8 Oct 09


On 31 Oct 2000, Singapore Airlines Flight 006, a Boeing 747-400 aircraft, scheduled for Taipei to Los Angeles, took off on the wrong runway 05R (that was closed for maintenance works and parallel to runway 05L which they had intended to take off) in bad meteorological conditions. Whilst on the take-off roll, the aircraft collided with construction equipment and crashed, resulting in 83 out 179 people being killed.

Analysis using 5-M Model



Qualification and Flying Record of the Crew

  • The primary flying crew consisted of the Pilot and Co-pilot. The aircraft captain had been a Captain for the Boeing 747-400 fleet since 1998 and had a total of 11235 hours of flying time.
  • The Co-pilot had been a First Officer since 2000 and had a total of 2442 hours of flying time.

Currency and Proficiency

  • From the aircrew records, both pilots were qualified and current for their flight. They were also current in simulator training. From interviews, both involved were assessed to be confident in carrying out their assigned duties.

Medical Status

  • Both pilot and co-pilot were physically well at the time of the flight. On review of past medical records, both pilots did not have any significant medical conditions of note. Both pilots reported that they had not consumed any medications or intoxicating beverage 72 and 48 hrs prior to the flight. There was no evidence to suggest alcohol or drugs were factors in the accident.

Physiological and Psychological Fitness

  • Both pilot and co-pilot were assessed to be psychologically and physiologically fit for the flight. The 2 crew had adequate sleep for the past 72 hrs prior, and were not fatigued on the day of the flight.


Aircraft Damage

  • The Aft fuselage separated from the remainder of the fuselage and was generally intact. The mid and forward fuselage suffered extreme fire damage. The left and right wing were heavily damaged by fire.

Aircraft History

  • The incident aircraft was serviceable on the day of the accident and the last maintenance performance was the A check at 17838 hrs, on 29 Oct 2000. The current airframe hours is 18459 hrs, 621 hrs since last service. A review of the maintenance logbooks revealed no related defects in the 30 days of Tech Log entries and showed no evidence that the aircraft was not airworthy.



  • Taiwan was affected by north-east monsoon flow and typhoon "Xangsane". The Taipei Meteorological Service issued a SIGMET for cumulonimbus, together with several gale and typhoon warnings which was applicable to the airport at the time of the accident.
  • Surface Weather observations at the time of the accident varied with winds at 020 degrees, 30 kts gusting to 61 kts, visibility was 450m, RVR was 450m, there was heavy rain, with broken clouds at 200ft and overcast at 500ft.

Airfield Lightings/ Markings/ Signages

  • The green taxiway lights immediately after 05R entry point into 05L were not serviceable and the following lights leading to 05L were degraded and dim.
  • There were no runway guard lights to depict that they the active runway way was ahead.
  • Taxiway centre line markings did not extend all the way down to the runway 05L threshold marking with interruption stops before the 05R threshold marking.
  • No runway markings to indicate that runway 05R was closed.
  • No visual warning/ signages or physical barriers to indicate maintenance works was in progress to prevent aircraft from lining up on wrong runway.
  • Due to heavy winds and rain, concrete barriers instead of frangible ones with red obstruction lights (that were not visible in low visibility) were used to demarcate the construction areas.


  • The flight crew received a pre-flight briefing package with pertinent information such as weather and NOTAMs highlighted; they were aware of the NOTAMs that stated that runway 05R was closed and takeoffs and landings were prohibited and certain sections were available for taxy.
  • Ground radar to pick up aircraft's position in low visibility was not installed due budgetary constraints. Hence there was no concrete plan to deal with low visibility operations.


  • The mission complexity was getting higher due to weather conditions deteriorating with the typhoon getting closer to the airport.


Investigations deemed that Machine was non-contributory. However, Man, Medium, Mission and Management had varying degrees of involvement toward the outcome of this flight. Significantly, Man and Management were pivotal factors, both of which could have mitigated the risks involved.


  • The pilot and co-pilot did not review the taxy route in a sufficient manner by making use of airport charts available to ensure that the route entailed taxiing pass 05R before entering 05L.
  • The pilot did not make use of the Para-visual display in the cockpit prior to take off which would have indicated that he had lined up on the wrong runway.


  • Reduced visibility in darkness and heavy rain diminished pilot's ability to see airfield's markings, lightings and signages.


  • Airport Management failed to conform to ICAO Annex 14 (Aerodrome Standards) in its airfield markings, lightings and signages.
  • Airport Management failed to notice these deficiencies during design verification, work completion certification and in day to day maintenance and inspection.
  • Airport Management did not cater for an independent audit/ assessment of airport to ensure facilities met international safety standards and practices.


  • Due to worsening weather conditions, pilot's hastened their departure to avoid flight delay which could have influenced pilot's decision making and loss of situational awareness in the airfield.
1. Rodrigues, C.C. and Wells, A.T. (2003)Commercial Aviation Safety. McGraw Hill.
2. Aviation Safety Council, Taiwan (2000). Aircraft Accident Report of SQ006. Retrieved from the World Wide Web on 30 Sep 09 http://www.airdisaster.com/reports/ntsb/ASCAAR-02-01.pdf
3.Weiner, E.L., & Curry, R.E. (1980). Flight-deck automation: Promises and problems. Ergonomics, 23, 995-1011. 4.Lewis P,& Burrell,C (2009).Aircraft Accident Investigation: Introduction to Aircraft Accident Investigation Procedures. Retrieved 30 September.2010, from, www.docstoc.com.

Want to know more?

Wikipedia – SQ 006
This page in Wikipedia offers more detailed information about the occurrence.

Contributors to this page

Authors / Editors

Melanie AttanMelanie Attan

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