Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
30
Human error causes of fatal aircraft accident
constitute more than half of all aviation
accidents. Man continues to be a weak link
in the man machine dynamics of aviation. Advances
made in the design and reliability of avionics has
reduced technical system failure. Although there has
been a significant improvement in the training of the
aircrew to prevent human error accidents, human error
continues to be a leading factor in most of the fatal
aircraft accidents. Understanding and preventing
human error in aircraft accident remains the foremost
challenge in aviation safety. A review of 545 aircraft
accidents in US Air Force revealed that 52% of these
accidents were caused by human error [1]. In another
study by Naval Safety Centre wherein 308 Cat A
mishaps were studied, 178 (58%) were attributed to
aircrew error. 47% of the accidents were attributed to
the supervisory error, another form of human failure
[2].
Analysis of fatal human error aircraft accidents in IAF
Wg Cdr BK Umesh Kumar*, Gp Capt H Malik+
ABSTRACT
Human error causes more than half of all aviation accidents. Records of all the fatal human error
accidents available at Dte. of Flight Safety from 01 Apr 1996 to 01 May 2001 were analysed for various
factors such as age of the Pilot, total flying hours, type of aircraft and rating of the Pilot. Human factors
were analysed in detail for factors such as inexperience, breach of discipline and lack of situational
awareness. Pilot error accounted for 68% of all fatal aircraft accidents followed by Technical defect 22.9%.
Mig–21 is the commonest aircraft involved and accounted for 50% of all accidents. Nearly 50% of the
aircrew were aged between 24 – 26 years with mean service flying hours of 900 hours and 200 hours on type
with Ops/White instrument rating. Among the human factors incorrect decision accounted for 48.6% of all
accidents followed by lack of situational awareness (40%) and Poor Skills (36%). Weather accounts for
10% of all fatal aircraft accidents.
IJASM 2003; 47(1) : 30 - 36
KEY WORDS: Human Factors, Fatal Accidents
* SMO, 12FBSU, AF. C/O 56 APO
+ DMS (AM) AIR HQ (RKP)
Original Articlethods in Aerospace Medicine
Material and Methods
Records of all the fatal aircraft accidents
available with the Directorate of Flight Safety from 01
April 1996 to 01 May 2001 were analysed. Various
factors analysed were :
(a) Age of the pilot : Age of the pilot till date of
accident was noted to determine the most
frequently involved age group in fatal aircraft
accidents.
(b) Flying hours of the Aircrew : in terms of
total service flying and flying hours on type
were also noted.
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
31
(c) Rating of the pilot : Rating and category of
pilots were noted. In case of fighter pilots the
instruments ratings are White, Green and
Master green. In case of transport and
Helicopters flying category is classified into
D-White, C-White, C-Green, B-Green and
A-Master Green. Instructor category classified
into C, B, A2 and A1.
(d) Last leave period : Period of absence from
flying was noted (in terms of months) since
aircrew availed his last leave.
(e) Past history of accident : Past history of
accident in terms of ejection, crash landings.
(f) Visibility : Visibility in Kms.
(g) Terrain : Operating terrain was noted to find
out any cause / relation with accident.
(h) Aircraft involved : Type of aircraft involved in
the accident.
(i) Mission : Type of mission to determine which
type was most frequently involved in the
aircraft accidents.
(j) Time of flight : Time of flight to find any
relation of time with accident.
(k) Ground Crew Errors : Ground crew errors
were classified into errors of ATC, Met
personnel and radar personnel including
servicing crew holding themselves directly or
indirectly responsible for the accident.
(l) Aircrew Errors : Were analysed in depth
under following heads [3] :-
(i) Inexperience : In terms of total flying
hours, flying hours on type, type of
mission and type of terrain.
(ii) Habit interference : Accidents due to
the factors such as changing over from
one aircraft to another.
(iii) Breach of disciplines : Violation of
existing orders and instructions.
(iv) Supervisory inadequacy : In terms of
failure to lead the mission lapses in the
duties of supervisor.
(v) Poor skill of flying : As noticed by the
COI.
(vi) Improper handling of controls : Such as
steep turns with high angle of attacks,
rough handling of controls.
(vii) Lack of situational awareness : Lack of
situational awareness was classified into
three levels [4]. Level - 1 Failure to
perceive the situation, Level - 2 Failure
to comprehend the situation and Level -
3 Failure to project the situation into the
future.
Results
Total number of Aircraft accidents from 01
April 96 to May 2001 was 48. The distribution of
accidents depending on the type of Aircraft is given
in Table-1.
Table - 1
MiG-21 24
MiG-23 01
MiG-27 05
MiG-29 02
KIRAN 03
ISKARA 01
AN-32 01
AVRO 01
CHETAH 03
Mi-8 03
HPT-32 03
Mi-17 01
The causes of fatal aircraft accident has been
divided into four categories namely human error
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
32
aircrew [HE(A)], human error ground crew [HE(S)],
Technical defect [TD], bird hit and unresolved [UN].
Their distribution is as follows :
HE (A) 32
HE (S) 01
TD 11
UN 02
BIRD HIT 02
Age of the aircrew : Age varied from 23 years to 34
years with mean age of 28.5 years. 50% of the
aircrew were in the age group of 24 - 26 years.
Total service flying varied from 63 hours in a U/T
pilot flight cadet to 3150 hours in a helicopter pilot.
Rating of the pilot involved in the air crash is as
given below.
U/T 01
OPS / UN RATED 09
OPS / White / D - White 13
Green / B-Green 07
A Master Green / Master Green 02
It is clearly seen from above that most
frequently involved aircrew in terms of category are
Ops White / D - White.
Last leave in correlation with the accident
showed that 24 aircrew had taken leave beyond six
months and 7 had availed leave less than six months.
Break in Flying Analysis showed that only 3
out of 32 had break in flying.
Past history of accident only one Aircrew had
a past history of ejection.
Flying condition total number of aircrew on
VMC and IMC was 26 and 6 respectively.
Visibility : On analysing the visibility of the area
where the accident took place it was seen that in
conditions where the visibility was more than 6 km
there were 13 accidents, 4 - 6 km 15 accidents, 4 km
in 3 accidents and in only one case visibility was less
than 200 Mts.
Terrain : There were 14 accidents in desert terrain,
12 accidents in plains and 6 were in hilly terrain.
Type of mission : Were classified into various types
such as Ground attack, Air attack, Tactical and
Miscellaneous. Ground attack included all stories at
Range, Valley attack, BAS. Air combat included PI, 2
VS 2, 1 Vs 1 and scramble. Tactics included medium
level tactics, Low-level tactics and close formation.
Lastly miscellaneous group included sorties such as
aerobatics, ferry, A&E checks and IF (Instrument
flying). It was seen that there was an almost an
equal distribution of Aircraft accidents in all the
categories. There were 9 ground attack sorties, 8 Air
Combat sorties, 9 tactical sorties and 6 miscellaneous
sorties.
Time No of Accidents
0600-1100 13
1100-1600 17 (1300-1500-10)
1800-200 02
It was seen that nearly more than 50% of the
accidents took place in the time zone between 1100 -
1600 hours. Out of this time zone 1300 - 1500 hours
accounted for 10 fatal aircraft accidents.
Human errors were analysed in detail and the
distribution of errors is as shown under :-
(a) Inexperience as contributory cause of accident
was found in ten cases. Their distributions
were as under :
(i) Inexperience on aircraft 05
(ii) Inexperience on type of mission 02
(iii) Inexperience on Situation 02
(iv) Inexperience on terrain 01
(b) Breaches of discipline were found in four
aircrew. The type of breach of discipline were
as under :
(i) Deliberate low flying 01
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
33
(ii) Not maintaining adequate distance
during take off 01
(iii) Not adhering to the SOP’s 01
(c) Supervisory inadequacies included various
factors such as :
(i) Wrong R/T calls 02
(ii) Incorrect manoeuvre by chase 02
(iii) Assigning the task beyond the
capabilities of pilots 03
(iv) Improper briefing 01
(d) Poor skill was attributed in 12 fatal crashes.
Type of poor skill was as under :
(i) Mishandling of controls 06
(ii) Flapless approach for landing 01
(iii) Selection of wrong fuel mixture 01
(iv) Negotiating a pull 04
(e) Fatigue was attributed in 03 cases. One of
them was attributed to chronic fatigue and
another two were attributed as acute fatigue.
(f) Not seeking help : This was seen in 03 cases.
In 02 cases pilot did not seek help from the
radar and in one case he did not seek the
help of buddy.
(g) Incorrect decision : This was seen in 15 cases.
Incorrect decision varied from getting into
high angles of attack which was present in 6
cases and getting in to clouds was seen 2
cases. This was the major factor in human
errors accounted for 48.6% of all the fatal
aircraft accidents.
(h) Poor Airmanship was mainly seen as ignoring
the Ground Proximity Warming Signals
(GPWS), incorrect procedures and ignoring the
radio altimeter warming. This was seen in 5
cases, which accounted for 15.6% of all the
human error accidents.
(i) Lack of Situational awareness was attributed in
13 cases. Their distribution were as under :
SA Type 1 6
SA Type 2 5
SA Type 3 2
(j) In three accidents failure of the Air traffic
controller was attributed as major factor.
(k) Meteorology as a contributory cause of
accident attributed in three cases wherein Met
section failed to inform the development of
Cumulus clouds after take off.
Discussion
Pilot error continues to be one of the major
factors in fatal aircraft accidents. Data varies with
various studies. In our study we found that pilot
error in fatal aircraft accidents dominated the list with
68%. Technical defect accounted for 22.9% of fatal
aircraft accidents. Percentage of unresolved fatal
accidents was 4.16%.
MiG-21 contributed to 50% of all our fatal air
crashes from April 1996 to May 2001. This is
because MiG-21 is the backbone of Indian Air Force
fighter flying. Every fighter pilot goes through the
MiG-21 flying before they are converted to other
types of fighter aircraft. The next common aircraft
was MiG-27, which accounted for 10% of the total
aircraft accidents. This could be because of the role
assigned to MiG-27, which is basically a ground
attack aircraft.
There have been two mid air collisions in a
five-year span involving MiG-21 aircraft from the
training Squadrons. This rate is high hence a special
attention should be given to collision avoidance
during training flights in the traffic pattern where midair
collisions occur involving the instructional flights.
Presently, avoidance of mid-air collision in VFR
primarily depends on the pilots to see and avoid the
aircraft. To prevent collisions in the traffic pattern, all
the pilots should report their positions and intentions
as they approach the airport and turn on to each leg.
On analysing the age of the aircrew involved
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
34
in the fatal aircraft accident it is seen that nearly 50%
of the aircrew belonged to the age group between
24-26 years. This is a “hot pants†carrier of aircrew,
wherein aircrew can get into any bravery acts. This
could be one of the reasons where in he may get
into a situation because of his bravado and he may
not able to get out of the situation later. This group
needs to be watched carefully in the Squadrons.
When fatal aircraft accidents analysed with
their total service flying and flying on type it was
found that pilots on MiG-21 with 200 hours of flying,
MiG-27 with 400 hours and a much higher hours of
flying in helicopter and transport aircrew i.e. 595 and
1318 hours respectively. It was also seen that
category of pilots with White instrument rating with
fully ops was more frequently involved in the aircraft
accident compared to any other category. This is
similar to the study by Li G et al wherein decreased
aircraft accidents with higher instrument rating [5].
Younger pilots with d/ops or non-ops are more rules
bound and he would complete the mission if all the
requirements were met. In case of fully ops / white
rating pilot he may take the aircraft to extreme
situation with his skill which may be limited.
Helicopter / transport aircrew with vast flying
experience when involved in fatal aircraft accidents,
complacency could be one of the reasons.
Our study did not find any correlation
between the type of mission and the accident.
Incidence of aircraft accident was almost same in all
types of mission.
Break in flying was found in only three pilots
and in one it was found to be significant and
contributory to the fatal aircraft accident. Presently
IAF has a policy of re-inducting the aircrew into
fighter flying after a long break i.e., two months for
day flying and three months for night flying. Aircrew
are given a dual check before he is re-flighted to
fighters.
There was only one pilot with a past history
of ejection. However there was no involvement of
other aircrew in any type of accident/incident
previously. This clearly rules out the possibility of
empirical foundation such as accident proneness,
which had become part of the tactical armamentarium
used in blaming the victim for occupational injuries.
Time of accident played a vital role in our
study. We found that nearly 60% of accidents
occurred from 1100 - 1600 h and out of which 10
occurred during 1300 - 1500 h. It could be because of
fatigue or because of low level of alertness. Another
probable reason is hypoglycaemia, which is bound to
occur during this period.
Pilots are not expected to be superhuman
beings. Therefore it must be accepted that they will
make mistakes. Some of these mistakes will have
disastrous consequences. It will be prudent on the
investigating agency to find out the gross violation
of orders and procedures or where in pilot has
exhibited poor airmanship, which has led to the
accident. It is also true that the aircrew who commits
mistakes can never be a repeater if it is a fatal crash.
Pilots actions do not take place in a vacuum
but are shaped by many factors including policies,
aircraft characteristics, presence of other pilots,
contact with ATC and a great variety of other
environmental determinants. It is also seen that in a
similar situation one is able to come out of the
situation compared to the other. Hence most of the
human factor in pilot error is relative to the general
error of pilot population.
Inexperience attributed as a factor of accident
in nearly 20% of the fatal accidents. Our study
percentage was similar to that of US Air Force in
instructional flights wherein 28% of all the fatal
aircraft accidents were attributed to inexperience. This
can be improved by improvement in emergency
perception / decision making. Other factors, which
include are selection, training and improvements in
the hardware both in terms of reliability and man
machine compatibility [6].
Breaches of discipline accounted for 12.5% of
aircraft accidents. Reasons for the violation of SOP’s
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
35
are not clearly established. It could be because of
thrill of flying or ‘one up manship’. One of the means
by which this can be curbed is by serious
punishments for those who violate existing orders or
SOP’s. This will be a hindrance to others, which will
help in preventing further air crashes. Incorrect
decision amounted for 48.6% of all fatal aircraft
accidents. Study results are similar to that of Billings
and Raynard WD [7]. This could also be because
of inadequate stress coping as suggested by Alkov
et al [8].
Supervisory inadequacies were seen 20% of
the total fatal aircraft accidents. Major inadequacies
included wrong R/T calls, not assessing the
capabilities of the junior and incorrect manoeuvre by
chase. In our study most often Flight commander was
one of the supervisors. He has to handle so many
variable jobs at the same time. It requires a separate
study to assess the stress level of flight commanders
and their chances of error / inadequacy during their
tenure.
Over keenness was seen in one, wherein the
pilot was keen to get the target while forgetting the
flying parameters. This must be emphasised at all
range sorties especially in young aviators to avoid
accidents in future.
Poor skill of flying mainly exhibited by young
aviators in which mishandling of controls accounted
for nearly 50% of the poor skill. Other factors that
included in the poor skill were selection of wrong fuel
mixture, insufficient altitude during the mission. Major
causes for exhibiting the poor skill are not practicing
the emergencies, casual attitude and preoccupation
with other things [9].
Nearly 10% fatal aircraft accidents have been
attributed to fatigue as one of the major factor. It is
long known that fatigue leads to aircraft accidents. In
our study we found that long time fatigue in one
case and short time fatigue in two cases as a
causative factor for the accident.
Nearly 15% of Aircrew displayed poor
airmanship qualities wherein they have ignored GPWS
(Ground proximity warning systems) warning and
Radio altimeter warning. Lack of situational awareness
accounted for nearly 40% of all the fatal aircraft
accidents. This was mainly due to failure to monitor
the data or misperception of data. In two cases
controller had lack of situational awareness and lead
the aircrew from a normal situation into an accident.
Misconception is another factor, which had lead to
lack of situational awareness. Misunderstanding of
information due to task saturation occurred in 4%
compared to 2.3% of US study by Jones et al [4].
Weather accounted for nearly 10.6% of fatal
aircraft accidents. In one case weather was below
captains minima and in another development of CB
was not informed to the aircrew.
Conclusion
This study gives an insight into the various
factors associated with fatal aircraft accidents. Man
continues to be a weak link in the man machine
dynamics. However better selection, training and
good supervision will definitely reduce/ avoid pilot’s
errors to the minimum. This study provides valuable
data in understanding the aetiology of pilot error and
formulating the prevention strategies. It also provides
evidence that pilot error is not merely a function of
human nature rather it is determined by both
exogenous and endogenous variables which are at
times predictable. Environmental stresses that
increase performance demand often play an important
role in the causation of pilot error and fatal aircraft
accident.
To minimise pilot error, enhancing performance
ability through safety training may be beneficial but
has its limits. Developing and applying technologies
that reduce pilot performance in dangerous situations
appear to be more effective.
“A typical fatal accident prone aircrew can be
described as Pilot aged between 24 to 26 with Ops /
White category on a MiG-21 with nearly 200 hours of
flying on type, flying between 1100 hours to 1600
Ind J Aerospace Med 47(1), 2003
Analysis of fatal human error accidents in IAF: Umesh Kumar
36
hours, committing mistakes either in the form of
mishandling of controls or exhibiting poor skills with
lack of situational awarenessâ€Â.
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