Flight_International 28Jan2020

(Jacob Rumans) #1


14 | Flight International | 28 January-3 February 2020 flightglobal.com

In both cases, jets became airborne too close to far end of Lisbon runway after intersection departures



wo identical serious take-off
incidents within two weeks
involving EasyJet Airbus A320s
at Lisbon have spurred UK
investigators to advise Portugal’s
airports operator to stop using
confusing terminology for
runway departure positions.
Both incidents involved the
aircraft accelerating with
insufficient thrust and becoming
airborne close to the far end of
the runway.
The UK Air Accidents Investi-
gation Branch (AAIB) says an
A320 bound for London Luton
on 24 April 2019 had intended a
departure from the S1 intersec-
tion of Lisbon’s runway 21.

It states that for “reasons
described as historic”, the
aeronautical information publi-
cation for Lisbon refers to runway
take-off points as “positions”,
unlike airports elsewhere.

While calculating take-off perfor-
mance criteria with the electronic
flightbag, the pilots both based
the calculation on the take-off
position designated “PSNSTMP”
(temporary position S), believing
it to refer to the S1 intersection.
But this designation actually
stood for the S4 intersection,
used for a full-length runway
take-off of 3,800m (12,500ft),

which would have allowed a
lower thrust level.
The crew did not crosscheck
the take-off distances available
from the two positions and, as a
result, failed to detect the error.
Although the A320 ultimately
departed from the nearby U
intersection, the available take-off
distance was still only 2,410m –
nearly 1,400m less than the full-
length runway.
The incorrect performance cal-
culation meant the A320’s thrust
was too low for the departure.
Although the captain mentioned
that the take-off roll “felt wrong”,
says the inquiry, full take-off
thrust was not selected.

Flight-data recorder analysis
shows the aircraft’s ground roll
was 1,860m and it lifted off about
400m from the runway end, over-
flying the upwind threshold at
about 100ft.

The incident involving aircraft
G-EZTD was followed just 14
days later by an “identical” event
as another EasyJet A320 (OE-IJL)
operating to Paris on 7 May took
off 350m from the runway end. It
crossed the threshold at 75ft.
“Robust adherence to proce-
dures is a key defence against
such incidents occurring,” says
the inquiry, pointing out that
pilots often find reduced acceler-
ation difficult to recognise.
EasyJet has since taken steps to
prevent a recurrence including
issuing a notice to crews clarify-
ing take-off positions from
Lisbon’s runway 21, and raising
awareness of the two incidents
among pilots.
“We are aware of the report
and fully assisted the AAIB with
its investigation,” says the budget
carrier. “The safety of our passen-
gers and crew is always our high-
est priority.
“We take events of this nature
seriously and will always take
action to ensure we maintain the
highest standards of safety. As
highlighted in the report we
proactively took a number of
safety actions.”
It has also engaged with Airbus
with regard to future potential
protective measures.
Although Airbus is developing
a system for the A320 intended to
offer protection against incorrectly
calculated take-off performance, it
indicated to the inquiry that the
system in its current state would
not have warned the crews of ei-
ther EasyJet aircraft because the
runway remaining exceeded the
forecast take-off distance. ■


Portuguese airports warned

over ‘confusing’ terminology

AAIB calls for greater clarity after EasyJet has two identical take-off issues in a fortnight


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