Page 69 - World Airnews September 2020 Edition

SAFETY SAFETY

SAFETY: FLIGHT DESCRIPTION SAFETY: ANALYSIS

So what actually happened here and what caused this aircraft the left to 7 degrees left of runway heading. The indicated Indictor (PAPI) light system on the left side, although at the This type of accident is strongly influenced by human factors issues.

to depart the right side of the runway on a seemingly routine airspeed is 72 knots. time of the accident, it would have been on the right side of the Take-off is a high workload period for both pilots. The com-

night take-off. The engine thrust reduces from its maximum of 79.1% to runway as depicted in the photograph above. mander as pilot flying in this case would be dividing his attention

The commander stated that he followed the yellow taxiway idle as the commander rejects the take-off. The heading then The runway is 2291m long (plan view) and 45m wide (addi- between setting thrust while maintaining directional control and

centreline onto the runway and applied power without stopping. deviates 3 degrees to the right of runway heading again, before tional runway information). monitoring the airspeed increase. As this is a visual maneuver, his

The aircraft is equipped with a Flight Data Recorder (FDR) a large correction 15 degrees left of runway heading which This information is available in the Jeppesen Airway Manual primary focus is outside the cockpit. He has the windshield centre

which registers an indicated air speed (IAS) of 34 knots about allows the aircraft to regain the paved surface of the runway. and other commercial charting systems will provide similar pillar to his right, which in the case above may have obscured the

the time the aircraft steadies up on runway heading (232 During this second correction the right engine thrust increas- information. It is important because it allows us to develop a approaching runway edge/grass visual cue to a certain extent.

degrees M). es momentarily to 81.7%. The accelerations measured by the mental model of what we expect to see at the threshold. It may Human factors experts have pondered whether humans are

Eight seconds later there is a heading deviation of 2 degrees FDR are consistent with passage over rough terrain but there is seem like ‘a firm grasp of the non-essentials’ to pilots flying capable of processing more than one channel of information

to the right for about 2 seconds, followed by a correction to no indication of an initiating event for the initial yaw. predominantly VFR or scheduled operators who have been at a time – are we single channel or multi-channel processors?

flying in and out of the same airport for years. But for charter Despite the fact that people can do things simultaneously,

or business aircraft pilots who are continually operating to most contemporary evidence suggests that we have a single

unfamiliar airfields and for low visibility operations, it is vital to cognitive processing channel and that this channel has limited
know what you can expect to see. capacity. Although attention can switch rapidly from one item

SAFETY: ANALYSIS What about the standard markings? They are just that - stan- to another, it can only deal with one item at a time. Clearly,

dard, hence they are not repeated on every chart. Neverthe- a pilot conducting a take-off needs to be operating at a high
EXAMINATION OF THE ACCIDENT SITE the aircraft followed the yellow taxiway centreline as described less, standard markings form an important part of that mental level of mental arousal. The large volume of sensory input that

The airport operator conducts an examination of the site. The but that it lined up on the solid white line delineating the right model we are trying to develop as we self-brief. needs to be processed results in a high cognitive load. This in

results are set out with reference to the attached diagram. edge of the runway rather than the centreline. The runway edges would be delineated by a solid white line turn reduces the ability of the pilot to react to or process infor-

Under normal circumstances, it would be immediately obvi- (runway side stripe marking). The centreline markings consist mation that is unusual or does not align with the mental model

they have of the activity – in this case a take-off.
ous to the crew as they would have seen the grass on the right of uniformly spaced white stripes (30m long) and gaps (20m).
side of the runway; however, in this case there was the large At the threshold, there may be threshold markings or, to use Remember also that the copilot or pilot monitoring on this

dispersal area, to their right, which could be mistaken for the the more descriptive term, ‘piano keys’. These also give us flight may be predominantly ‘head-in’ at this point, reading

right side or half of the runway. some clue as to the width of the runway, with the 12 piano keys checklists, monitoring that take-off thrust is set, engine indi-

Without stopping, take-off power is applied. The aircraft ac- at Teeside confirming that the runway is 45m wide. cations are normal and that speed is increasing etc. A quick

celerates rapidly. The right main gear enters the grass at point Ahead of the ‘piano keys’ and symmetrically placed either glance outside in the initial part of this take-off would reveal an
expanse of concrete to left and right of a solid white line with

B and then encounters a drain cover 23 meters later near point side of the centreline, are the white runway designation mark- white lights. That looks normal doesn’t it? He now diverts his
C, which is at the edge of the disused runway. ings or ‘runway numbers’. attention back inside to continue monitoring. A few seconds

This causes the small 2 degree yaw to the right and may Putting all of that information together, what should the crew later he looks up, sees grass to the right, a rabbit running

account for the ‘bump’ felt by the crew. The aircraft is doing see as they line up prior to take-off? The yellow taxiway centreline towards the aircraft and then a bump, followed by a strong yaw

about 72 knots as is crosses the disused runway. The right main crosses the solid white runway edge line and piano keys to the to the right, 30 to 40 degrees as far as he could recall in the in-
gear as well as the nose gear now enter the grass once again centreline. On or just ahead of the piano keys, we should see the cident report. And this is all happening in a matter of seconds.

beyond the disused runway. The nose yaws 7 degrees left mo- white runway numbers ‘23’ directly ahead, symmetrical about the Quite often, pilots will erroneously alter than recollection

mentarily as a correction is made and the nosewheel enters the centreline. The stripes of the centreline are directly ahead, as are of an event to fit in with their mental model of it. In fact, the

paved surface. The Citation then deviates 3 degrees right once the associated centreline lights. (In fact, during IMC and particu- aircraft had yawed only 2 or 3 degrees to the right. Could the

again and the nose wheel departs the right edge of the runway larly during low visibility operations, we often count them to get a

a second time. In addition to full left rudder and differential crosscheck of the reported runway visual range.) The commander angle at which their take-off trajectory (about 232 degrees)

crossed the old disused runway (orientated about 190 degrees)
braking, the commander increases the thrust on the right en- stated in his report that he did not see any centreline lights at all. have altered his perception of the yaw angle? I have seen

gine and the aircraft yaws 15 degrees to the left. Its path then Solid white edge lines may be visible at night in the landing simulator debriefs where pilots were not aware that a large red

takes it back onto the runway. lights to left and right, although possibly not on such a wide

Note the yellow centreline of Taxiway Alpha which leads to runway. Nevertheless, the white runway edge lights should be fire light accompanied by the associated warning had activated

the threshold of runway 23. Notional point A is where the take- DEVELOPING A MENTAL MODEL plainly visible on each (and been silenced!)

off was assumed to start when the aircraft aligned with runway If we were to operate in or out of Teeside Airport on a charter, side of the Citation. during a take-off –

heading, but it was probably to the right of point A. A tyre mark what information would be available to us? A quick review of the The red component they had to be shown

is seen on the grassed area right of the runway between points current Jeppesen 10-9 page (included below) reveals the following: of the PAPI lights the debrief video of

B and C. Point B is 140m into the take-off run (right main gear). • The airport plan view depicts taxiway A leading to holding should be visible to the event.
There is a further tyre mark at point D which continues across point A1 at the threshold of runway 23. This is also desig- the left or the right The bottom line is

the disused runway and into the grass again at point E. At point nated as a hotspot. of the runway as that we humans are
E, a second tyre mark is seen entering the grass, but closer to • The dispersal area is shown to the right (or northwest) indicated on the Jepp not efficient proces-
the runway (nose gear). of the threshold in grey, so we know it is not part of the 10-9 chart in visibility sors of information
Both tyre marks now deviate to the left as the PAPA light runway which is depicted in black. greater than 300m under conditions of

structure is approached and the tyre nearer the runway returns • The chart shows an RVR transmissometer to the north- RVR. PAPI lights are high workload. As a
to the paved surface. The main tyre track parallels the runway west of the dispersal area. not something that result, we need to
before deviating to the right again and the second tyre track are usually associat- ensure that as much

appears once more. Both tracks then gradually turn to the left • The disused runway crossing runway 23 near the thresh- ed with take-off, the as possible is in

old end is depicted as a line of grey Xs’.
and return to the paved surface at point F. point being that if you order with errors/dis-
crepancies resolved

An extensive search for the reported hare/rabbit or its re- In the additional runway information section in the middle line up on what you before proceeding

mains yields no result. block of the 10-9 chart there is a note stating that aircraft requir- think is the runway
ing more than runway width to turn should do so at the runway centreline and find to a high workload

MECHANICAL INSPECTION ends where extra width (the dispersal areas) is available. them directly ahead of phase of flight such as

The aircraft is examined but no fault is found which could In terms of lighting, the runway is equipped with white high you, it could be taken take-off or approach

and landing.

account for the yaw described by the crew. intensity runway lights (HIRL) spaced 60m apart, demarcating as a subtle cue that all
the edge of the runway. White centreline Lights (CL) spaced is not well. Pilots are typically
MOST LIKELY SCENARIO 30m apart demarcate the centreline. reluctant to stop, slow
The available flight data and ground witness marks suggest that Today, the 10-9 chart shows a Precision Approach Path HUMAN FACTORS down or hesitate on

World Airnews | September 2019 World Airnews | September 2019
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