investigators are urging ATR operators to check fuel gauges on their aircraft
after discovering the Tuninter
ATR 72 lost in a fatal accident off Sicily
last month was fitted with a fuel-quantity indicator meant only for ATR 42s.
body Agenzia Nazionale per la Sicurezza del Volo (ANSV) states that examination of the wreckage
from the crashed aircraft – which ditched north of Palermo on 6 August after
suffering a dual engine failure – plus the study of documentation shows that an
incorrect instrument had been installed.
ANSV stresses that the investigation is continuing, it has issued two emergency recommendations to the
European Aviation Safety Agency (EASA) and Italian civil aviation authority Ente Nazionale per l’Aviazione
Civile (ENAC) following the
recommendation urges operators to check that their ATR 42s and 72s have the
appropriate fuel gauges installed, while the second suggests that a
modification be introduced making it impossible to fit the wrong gauge to
either aircraft type.
says that the fuel-quantity indicators for the ATR 42 and 72 are physically
similar and that it is possible to fit the wrong gauge to either’s instrument
panel. But differences in the internal algorithms mean that the wrong gauge
would not register the correct quantity of fuel on board.
have shown that if a fuel-quantity indicator meant for an ATR 42 is installed
on an ATR 72, the cockpit display shows a fuel level greater than that which is
actually present,” says ANSV, which has performed several experiments on an ATR
72 to assess the effects of interchanging the instruments.
72 aircraft have a total fuel capacity of 5,000kg compared with 4,500kg for the
smaller ATR 42.
of the 39 occupants on board the Tuninter
service between Bari and Djerba died as the aircraft attempted an emergency
landing at Palermo.
a message to all operators of the turboprops, ATR says that a shortage of fuel
is among the possible causes of the accident. It says that the manner in which
the central fuselage and wing sections continued to float after the crash, plus
the lack of fuel traces at the crash site, support a fuel-exhaustion scenario.
reported value of the fuel indication at the time of the double engine
flame-out supports the hypothesis of a potential inappropriate…installation of
a fuel-quantity indicator on the ATR 72 aircraft concerned,” says the
manufacturer. “This configuration could imply an over-estimated fuel quantity
all-operator message also states: “ATR reminds operators to strictly comply
with existing aircraft maintenance manual requirements.”
spokesman for ATR says that the company believes that its maintenance manuals
for the type are “clear enough” in detailing the need for operators to install
only specifically-listed items during overhaul work.
says that the fuel-exhaustion theory remains “one of the different hypotheses”
under study by the Italian investigators and that it is too early to say how ATR
will respond to recommendations to prevent inadvertent incorrect installation
of the fuel gauges.
says that the investigation is still progressing and that the analysis of the
cockpit-voice recorder and flight-data recorder from the aircraft should
provide much more information on the issue. EASA has yet to respond formally to
the Italian recommendations.