Overrun Accident at Bangkok, Thailand, 23 September 1999
Boeing 747-438, Callsign: Qantas One
Forse il pubblico e i media
non hanno prestato molta attenzione a questo accident, altrimenti non
sarebbero mancati i commenti sul crollo del safety record della compagnia
considerata la più sicura al mondo.
"I want to fly with Qantas" insisteva il personaggio autistico interpretato
da Dustin Hoffman in "Rain Man", anche a costo di andare da Los Angeles
a San Francisco passando per Sydney.
In ogni caso, ancora una volta l'investigazione dimostra che nessuno può
assegnare voti sulla sicurezza in base alle statistiche passate, anche
se appaiono consolidate. Quando si va a scavare nel sistema si
trovano carenze latenti
e
azioni scatenanti che
lasciano piuttosto perplesso chiunque abbia fatto la professione di pilota
di linea con una costante attenzione ad ogni evento, incidente o catastrofe.
Un'attenzione costante ai fattori di causa la cui conoscenza poteva significare
una possibilità futura di evitare comportamenti errati in condizioni
analoghe a quelle in cui tali fatti si erano verificati.
La perplessità sorge dal fatto che ancora una volta non c'è
niente di nuovo nella dinamica degli incidenti di "overrun" in atterraggio
con la pista bagnata.
Abbiamo citato nell'editoriale l'incidente del DC-8 Swissair ad Atene.
Confrontate la causa probabile del riporto
sinottico
con quello che è accaduto a Bangkok; ci sono più di vent'anni
tra i due eventi e molti altri ce ne sono stati in quest'intervallo di
tempo.
Analogamente ad altre tipologie di incidenti, come i cosiddetti CFIT [Controlled
Flight Into Terrain] dove il comportamento dei piloti ricorre con le stesse
modalità, ci si trova a constatare che tutti questi piloti non
erano edotti delle trappole comportamentali nei quali altri erano finiti
prima di loro.
Imparare dagli incidenti, come viene detto anche in altre parti di questa
edizione, è più importante di qualsiasi altra forma di educazione.
Ed è la base su cui ogni professionista del volo costruisce la
propria airmanship.
Questa investigazione è stata condotta dall'ente australiano ATSB
con canoni che vanno oltre le norme ICAO, nel senso che tali norme vengono
applicate compiutamente ma l'individuazione dei fattori causali percorre
puntualmente la teoria dell'Organizational Accident proposta dal Prof.
James Reason.
Di questa teoria, a cui si riferiscono ormai tutte le maggiori organizzazioni
internazionali che regolano i sistemi a rischio di incidente rilevante
o che compiono investigazioni sugli incidenti [ICAO, NTSB, AAIB, ATSB,
TSBC, IMO], abbiamo spesso parlato nel nostro sito e l'abbiamo illustrata
dettagliatamente nel nostro libro "La
strategia del margine"
che è, credo, l'unica trattazione in lingua italiana dell'argomento.
In una scorsa edizione abbiamo illustrato anche un incontro avuto con
il Prof. Reason in occasione del convegno:
Errore
umano e medicina
L'intervento di J.Reason al 1° Congresso Internazionale di Torino
La lettura del rapporto
ATSB sull'incidente Qantas ci pone di fronte ad un'altra realtà.
L'evento accadde nello stesso periodo in cui un MD80 in atterraggio a
Fiumicino finì fuori pista per problemi di controllabilità
e di arresto sulla pista bagnata.
Non credo che da noi si possa pretendere un'investigazione ed un rapporto
analogo a quello dell'ATSB su un evento sostanzialmente analogo [ancora
una volta non ci sono nuovi fattori causali e molti incidenti sono quasi
fotocopie] ma almeno un rapporto sommario, come altri recenti che abbiamo
illustrato e costruttivamente criticato.
Overrun
a Genova - commento al rapporto finale
Relazione
dell'Inchiesta Tecnico-Ministeriale su un SERIOUS INCIDENT di un MD80
in atteraggio a Linate
Relazione
dell'inchiesta tecnico-ministeriale relativa al grave inconveniente occorso
il 4 - agosto - 1999 presso l'aeroporto di Reggio Calabria
Ma le riflessioni
a cui siamo costretti nello scorrere il rapporto ATSB vanno ben oltre.
Diversi dubbi ci colgono sulla professionalità (airmanship) dei
piloti [non solo quelli coinvolti nell'incidente], sulle norme delle compagnie
e sulla capacità di controllo degli Enti di Stato specialmente
quando ci troviamo di fronte ad un evento che riguarda uno dei paesi all'avanguardia
nell'aviazione, ad un'inchiesta che mette a nudo senza remore le strutture
organizzative della maggiore compagnia e dell'ente di normativa australiani.
D'altra parte in Australia la messa a terra dei B767 Ansett per problemi
di manutenzione "potrebbe" essere la prova ulteriore che l'ATSB e la CASA
agiscono correttamente senza guardare in faccia nessuno e senza nascondere
niente. Dico "potrebbe" perché potrebbe anche trattarsi di "giochi
di potere" industriale tra compagnie. In ogni caso dobbiamo dare atto
di coerenza, professionalità e assolvimento della funzione primaria
di salvaguardia del pubblico che viaggia in aereo. Quali garanzie ha lo
stesso pubblico in relazione a quanto avviene in molti altri paesi? E
qui vi rimandiamo alle considerazioni dell'editoriale.
Si deve infine notare la decisione dell' Aircraft Accident Investigation
Committee of Thailand di delegare l'inchiesta all'ATSB, un evidente riconoscimento
di capacità, competenza e risorse che dovrebbe essere la prima
norma di un ente che abbia lo scopo di condurre investigazioni di incidenti.
Se qualcuno è in grado di svolgere tale lavoro con maggior efficacia
è necessario delegare e, naturalmente, partecipare per capire e
imparare. L'aviazione di linea è una faccenda globale ed un incidente
può sempre far emergere fattori che devono essere universalmente
conosciuti. Per questo è bene rivolgersi a chi dà le maggiori
garanzie che tali fattori vengano alla luce.
Quello che vi proponiamo, con qualche commento, è l'Executive
Summary tratto dal rapporto completo di oltre 300 pagine che è
disponibile sul sito ATSB.
Ricordiamo che la Civil Aviation Safety Authority [CASA] è l'equivalente
della nostra ENAC e che l'Australian Transportation Safety Bureau [ATSB]
è l'ente che conduce investigazioni di incidenti in tutte le modalità
di trasporto del continente australiano.
In esso si è integrato il Bureau of Air Safety Investigation [BASI]
che sarebbe stato l'equivalente della Agenzia Nazionale per la Sicurezza
del Volo [ANSV]
EXECUTIVE SUMMARY
Overview
On 23 September 1999, at about 2247 local time, a Qantas Boeing 747-438
aircraft registered VH-OJH (callsign Qantas One) overran runway 21 Left
(21L) while landing at Bangkok International Airport, Thailand. The overrun
occurred after the aircraft landed long and aquaplaned on a runway which
was affected by water following very heavy rain.
The aircraft sustained substantial damage during the overrun. None of
the three flight crew, 16 cabin crew or 391 passengers reported any serious
injuries.
The Aircraft Accident Investigation Committee of Thailand delegated
the investigation to the Australian Transport Safety Bureau (ATSB)
on 18 November 1999. In accordance with this delegation, the ATSB conducted
the investigation according to the standards and recommended practices
of Annex 13 to the Convention on International Civil Aviation and
the Australian Air Navigation Act 1920, Part 2A.
In terms of overall accident statistics, runway overruns are a relatively
common event. Of the 49 accidents involving western-built high-capacity
jet aircraft reported during 1999, 11 were landing overruns. Landing overruns
typically occur when the runway is wet or contaminated and/or the aircraft
is high and fast during final approach.
The accident flight (see part 1)
The first officer was the handling pilot for the flight. The crew
elected to use flaps 25 and idle reverse as the configuration for the
approach and landing, in accordance with normal company practice (since
December 1996).
Questa tecnica di utilizzazione ha una sua logica in condizioni normali, cioè pista asciutta, assenza di precipitazioni, assenza di venti significativi, buona visibilità ma non in quella situazione che ai piloti doveva apparire estremamente marginale.
At various stages during the approach to runway 21L, the crew were informed by air traffic control that there was a thunderstorm and heavy rain at the airport, and that visibility was 4 km (or greater). At 2240, a special weather observation taken at Bangkok airport noted visibility as 1,500 m and the runway visual range (RVR) for runway 21 Right (21R) as 750 m.
In condizioni di visibilità considerevolmente ridotta a causa di pioggia, non esiste pista al mondo [ancor meno se è ungrooved] in grado di drenare l'acqua con un tasso sufficiente ad impedirne depositi stagnanti (standing water), quindi la certezza di trovarsi ad atterrare su uno strato d'acqua e di incontrare problemi di "aquaplaning" avrebbe dovuto essere presente nella valutazione dei piloti. D'altra parte questo dovrebbe essere il bagaglio di conoscenza di ogni professionista degno di tale appellativo.
The Qantas One crew was not made aware of this information, or the fact that another aircraft (callsign Qantas 15) had gone around from final approach at 2243:26. At 2244:53, the tower controller advised that the runway was wet and that a preceding aircraft (which landed at approximately 2240) reported that braking action was ‘good’.
Alla considerazione precedente si deve aggiungere che un pilota dovrebbe prendere con molto beneficio di inventario ogni pilot report che fornisce un quadro positivo e considerare maggiormente chi ha interrrotto l'operazione [a condizione di esserne informato]. L'esperienza ci dice che chi atterra in condizioni marginali fornisce (se richieste) notizie di solito tendenti a minimizzare i problemi. E' una questione formale e psicologica al tempo stesso. Molto pochi sono quelli che dicono di essere atterrati, essere riusciti a fermare l'aeromobile in condizioni da rizzare i capelli e poi affermare per radio che sarebbe stato meglio rinunciare e andare da un'altra parte.
The Qantas One crew noted no effect from the weather until visibility reduced when the aircraft entered very heavy rain as it descended through 200 ft on late final approach.
E' il momento in cui va in crisi la condotta dell'aeromobile perché la drastica e improvvisa perdita dei riferimenti visivi esterni fa abbandonare involontariamente il corretto sentiero di discesa ad una quota troppo bassa per riferirsi di nuovo al sentiero strumentale.
The aircraft then started to deviate above the 3.15 degree glideslope, passing over the runway threshold at 169 kts at a height of 76 ft. Those parameters were within company limits. (The target speed for the final approach was 154 kts, and the ideal threshold crossing height was 44 ft.) When the aircraft was approximately 10 ft above the runway, the captain instructed the first officer to go around.
La decisione giunge ancora in tempo per riportare l'aereo in aria, anche se avrebbe dovuto essere anticipata. Però diventa più un'azione di disturbo che un "take over". Quello che provoca subito dopo è il risultato di mancanza di pianificazione, pressione ad atterrare, delega di condotta [da parte del comandante] non correttamente interpretata, e di altri elementi di confusione.
As the first officer advanced the engine thrust levers, the aircraft’s mainwheels touched down (1,002 m along the 3,150 m runway, 636 m beyond the ideal touchdown point). The captain immediately cancelled the go-around by retarding the thrust levers, without announcing his actions. Those events resulted in confusion amongst the other pilots, and contributed to the crew not selecting (or noticing the absence of) reverse thrust during the landing roll. Due to a variety of factors associated with the cancellation of the go-around, the aircraft’s speed did not decrease below the touchdown speed (154 kts) until the aircraft was 1,625 m or halfway down the runway.
L'investigazione ha messo
in luce ragioni organizzative che hanno favorito il comportamento dei
piloti e che vanno attribuite alla compagnia Qantas e all'ente di controllo
CASA.
Esse sono un'attenuante ma non sufficiente a limitare la responsabilità
professionale del comandante.
La mancanza di Situational
Awareness [SA] in questo
caso è
evidente. La SA si fonda su una serie di pilastri di conoscenza e di preparazione
di cui ognuno è responsabile in quanto professionista.
[Vedere uno dei nostri
primi articoli: Airmanship
– Un modello concettuale ed operativo di riferimento]
Uno di questi pilastri
è costituito dalla consapevolezza che l'organizzazione della compagnia
non produrrà mai un decalogo comportamentale a prova di errore,
pertanto la ricerca di informazioni, la creazione di un proprio archivio
mentale, non può essere effettuata da altri se non dal professionista
coscenzioso e motivato alla massima sicurezza. Ed è preoccupante
constatare che chi è al comando di un B-747 può avere tali
pericolose lacune. Per non parlare della incertezza della necessità
di evacuare immediatamente i passeggeri dopo un fuori pista, illustrata
di seguito.
The investigation established that, during the landing roll, the aircraft
tyres aquaplaned on the water-affected runway. This limited the effectiveness
of the wheelbrakes to about one third of that for a dry runway. In such
conditions and without reverse thrust, there was no prospect of the crew
stopping the aircraft in the runway distance remaining after touchdown.
The aircraft overran the 100 m stopway (at the end of the runway) at a
speed of 88 kts, before stopping 220 m later with the nose resting on
an airport perimeter road.
The depth of water on the runway when the aircraft landed could not be
determined but it was sufficient to allow dynamic aquaplaning to occur
(i.e. at least 3 mm). The water build-up was the result of heavy rain
on the runway in the preceding minutes, and possibly because the runway
was ungrooved.
During the examination of the performance of the aircraft on the runway,
it became evident that the flaps 25/idle reverse thrust landing procedure
used by the crew (and which was the ‘preferred’ company procedure) was
not appropriate for operations on to water-affected runways. The appropriate
approach/landing procedure was flaps 30/full reverse thrust. This had
the characteristics of a lower approach speed, of being easier to fly
in terms of speed control and runway aim point (for most company pilots),
and of providing maximum aerodynamic drag after touchdown when the effectiveness
of the wheelbrakes could be reduced because of aquaplaning. Had this configuration
been used, the overrun would most probably have been avoided.
As with other company B747-400 pilots, the crew had not been provided
with appropriate procedures and training to properly evaluate the potential
effect the Bangkok Airport weather conditions might have had on the stopping
performance of the aircraft. In particular, they were not sufficiently
aware of the potential for aquaplaning and of the importance of reverse
thrust as a stopping force on water-affected runways.
Significant active failures
Significant active failures associated with the accident flight were:
• The flight crew did not use an adequate risk management strategy for
the approach and landing. In particular, they did not consider the potential
for the runway to be contaminated by water, and consequently did not identify
appropriate options and/or landing configurations to deal with the situation.
That error was primarily due to the absence of appropriate company procedures
and training.
• The first officer did not fly the aircraft accurately during the final
approach.
• The captain cancelled the go-around decision by retarding the thrust
levers.
• The flight crew did not select (or notice the absence of) idle reverse
thrust.
• The flight crew did not select (or notice the absence of) full reverse
thrust.
• The runway surface was affected by water.
Significant inadequate defences
Significant inadequate defences associated with Qantas Flight Operations
Branch activities were:
• Company-published information, procedures, and flight crew training
for landing on water-affected runways were deficient.
• Flight crew training in evaluating the procedural and configuration
options for approach and landing was deficient.
Post-accident events and cabin safety issues (see part 2)
The main areas of damage to the aircraft were the lower forward fuselage,
the nose and right wing landing gear and landing gear bays, and the engines.
Numerous cabin fittings dislodged during the accident sequence. As a result
of the nose landing gear collapsing rearwards and upwards into the lower
fuselage, the cabin passenger address system and the interphone system
for communications between the flight deck and the cabin became inoperable.
No evidence of fire was found during the post-accident examination of
the aircraft.
After the aircraft came to a stop, the flight crew initiated a process
of gathering information from the cabin concerning the extent of the aircraft
damage. The failure of the passenger address and cabin interphone systems
was a major hindrance to the crew’s efforts to assess the situation in
the cabin. Some important information regarding the cabin environment
and the external condition of the aircraft did not reach the flight crew.
In addition, there were gaps in the information available to the flight
crew, the possible significance of which was not considered by them in
deciding whether or not to keep the passengers on the aircraft. The captain
assessed that the appropriate response was to wait for outside assistance
and then conduct a precautionary disembarkation, rather than initiate
an immediate evacuation.
Normal radio communications between the aircraft and the control tower
were lost for a few minutes after the aircraft came to a stop. Additionally,
the aircraft could not be seen from the tower because of the reduced visibility
and the emergency response vehicles were restricted to sealed surfaces
by the wet conditions. These issues contributed to the emergency response
vehicles arriving at the aircraft about 10 minutes after the accident.
Approximately 20 minutes after the accident, the crew initiated a precautionary
disembarkation from the right side of the aircraft using the emergency
escape slides.
Although the disembarkation was achieved largely without incident, there
were arguably sufficient ‘unknowns’ concerning the condition of the aircraft,
and possible related hazards, for an earlier evacuation to have been conducted.
Significant active failures
Significant active failures associated with the post-accident events
were:
• The cabin interphone and passenger address systems became inoperable
(due to impact damage).
• The flight crew did not consider all relevant issues when deciding not
to conduct an immediate evacuation.
• Some crewmembers did not communicate important information during the
emergency period.
Significant inadequate defences
Significant inadequate defences associated with Qantas Flight Operations
Branch activities were:
• Procedures and training for flight crew in evaluating whether or not
to conduct an emergency evacuation were deficient.
• Procedures and training for cabin crew in identifying and communicating
relevant information during an emergency were deficient.
Another significant deficiency involved the aircraft cabin interphone
and public address system. The redundancy provided by the normal and alternate
cabin interphone and public address systems in B747-400 aircraft was compromised
because some components for both systems were co-located in the same relatively
damage-prone position in the lower fuselage aft of the nosewheel. Aircraft
design standards in the USA and Europe currently contain no requirements
for system redundancy in this sense. The report includes a recommendation
to the FAA and JAA regarding this deficiency.
Organisational factors: Qantas (see part 3)
The ATSB investigation examined the processes of the Qantas Flight
Operations Branch for any systemic organisational issues that may have
allowed the deficiencies mentioned above to occur. That examination included
a detailed review of the company’s introduction of the flaps 25/idle reverse
procedure, as well as company procedures and training relating to water-affected
runways. The aim of the new procedure was to reduce costs (e.g. brake
maintenance, noise levy charges at Sydney Airport, and thrust reverser
maintenance) without affecting safety levels. Examination of the project
development process revealed that a proper risk assessment of the new
procedure was not undertaken, and that other important considerations
were overlooked. There were also significant deficiencies in the manner
in which the company implemented and evaluated the new procedures.
Overall, the investigation identified five deficiencies related to the
organisational processes of the Qantas Flight Operations Branch:
• The processes for identifying hazards were primarily reactive and informal,
rather than proactive and systematic.
• The processes to assess the risks associated with identified hazards
were deficient.
• The processes to manage the development, introduction and evaluation
of changes to
operations were deficient.
• The design of operational procedures and training was over-reliant on
the decision-making ability of company flight crew and cabin crew and
did not place adequate
emphasis on structured processes.
• The management culture was over-reliant on personal experience and did
not place
adequate emphasis on structured processes, available expertise, management
training, and research and development when making strategic decisions.
Organisational factors: Civil Aviation Safety Authority (see
part 4)
Significant latent failures associated with CASA’s regulatory operations
were:
• The regulations covering contaminated runway operations were deficient.
• The regulations covering emergency procedures and emergency procedures
training were deficient.
• The surveillance of airline flight operations was deficient.
In June 1997, CASA began developing a systems-based approach to surveillance
because of deficiencies with the previous approach (which focussed on
the end products of the aviation system). However, the new system had
not reached maturity at the time of the accident. In 1998 and 1999, there
were serious shortfalls in CASA’s planned product-based surveillance of
Qantas flight operations. However, because of the significant limitations
in the effectiveness of product-based audits to identify the type of systemic
and organisational deficiencies highlighted during this investigation,
it was unlikely that a higher level of surveillance activity would have
revealed these deficiencies.
Safety action (see part 5)
On 5 December 2000, Qantas advised that all deficiencies identified
during the investigation and highlighted in this report either had been,
or were being, addressed. Qantas Flight Operations Branch had introduced
substantial changes and was examining further changes to its management
policies and procedures in the following areas:
• operational training and procedures
• hazard identification
• risk assessment
• change management
• design of procedures and training programs
• management decision-making processes
Some of these changes were in progress in the period before the accident.
The ATSB raised a number of safety analysis deficiency notices (SADNs)
concerning Qantas operations as a result of the investigation. Four of
these SADNs remained open pending advice from the company on the progress
of their change activities.
CASA was also in the process of making substantial changes to its surveillance
processes and the Australian aviation safety regulations. Many of these
changes were in progress at the time of the accident. The ATSB made four
recommendations where it considered that there remained safety matters
that were yet to be adequately addressed.
Prima di passare ad un paio
di notizie di agenzia, interessanti per la sintesi e per le reazioni della
Qantas, è opportuno richiamare il discorso sulla delega di condotta.
Non so come siano state stravolte le norme interne delle compagnie ma
so che la consuetudine secondo cui comandante e copilota si alternino
alla condotta dell'aeromobile ["chi fa la tratta"] è, appunto,
una consuetudine, non una norma inderogabile, e va attuata con atteggiamento
critico.
Senza citare ICAO o Codice della Navigazione, basti considerare la JAR-OPS
1.085,c:
"the Commander shall:
1) be responsible for the safe operation of the aeroplane and safety of
its occupants during the flight time;"
In altre parole l'addestramento e il mantenimento della capacità
di pilotaggio del copilota sono aspetti secondari che possono essere presi
in considerazione solamente se le condizioni operative non danno adito
a dubbi di sorta. Il comandante deve avere la ragionevole certezza di
avere margini sufficienti di intervento nel caso di grossi errori, quindi
la componente meteorologica non deve essere significativa come nel caso
di operazioni in presenza di windshear, forti piovaschi ed altre condizioni
marginali.
In ogni caso, qualora un comandante decida di delegare il pilotaggio,
non dovrà mai delegare di fatto anche gli aspetti decisionali,
per cui è necessaria una pianificazione accurata che consideri
le alternative possibili e predisponga a comportamenti appropriati.
«I passeggeri pagano per la miglior qualità della condotta dell'aeromobile»
Quando il
Comandante Silvano Imparato era Direttore Operazioni Volo Alitalia volle
che il Manuale Operativo di Compagnia contemplasse in modo inequivocabile
un richiamo ai comandanti ad esercitare la massima cautela nel delegare
la condotta al copilota in particolari condizioni di cui venne fornito
un elenco a titolo di esempio.
Avevo l'incarico di Flight Operation Quality Assurance ed ebbi il compito
di preparare il documento di riferimento per l'approvazione al Comitato
degli Standards ma la cosa non ebbe seguito a causa della cessazione dei
nostri rispettivi incarichi.
E' forse il caso che il Comandante Imparato riproponga tale raccomandazione
nel suo nuovo incarico all'ENAC?
Non credo che le esortazioni
o le raccomandazioni possano scalfire un'indifferenza congenita mentre
credo che la riproposizione ad nauseam degli incidenti e degli esiti dell'indagine
che pesano sul comportamento del comandante possano smuovere anche i meno
attenti da un acritico adeguamento del proprio comportamento a consuetudini
spesso pericolose.
Per questo invito i professionisti di buona volontà a rileggersi
questo vecchio ma sempre attuale articolo:
Documento:
Awareness of stresses associated with approaches and landings under marginal
conditions - J.S. Clauzel
(english)
Media Release of QF1 Bangkok accident investigation report
The Australian Transport Safety Bureau
today released its report on the Qantas B747-400 runway overrun
accident at Bangkok International Airport on 23 September 1999.
The ATSB investigation was undertaken
under a delegation from the Aircraft Accident Investigation Committee
of Thailand given on 18 November 1999.
ATSB Executive Director Kym Bills said:
"The Qantas Bangkok runway overrun was a serious accident that fortunately
did not result in fatalities and serious injuries. It was a wake-up call
to Qantas who may have been lulled into a false sense of security by their
very good safety record. Qantas provided excellent cooperation throughout
the investigation and ATSB is pleased that Qantas has actively responded
to the deficiencies found during our investigation."
"Like most major accidents, QF1 resulted
from a complex mixture of active failures, inadequate defences
and organisational factors - these are spelled out in our investigation
report without fear or favour but not apportioning 'blame'."
The investigation found that the accident
occurred when the B747-400 landed well beyond the normal touchdown zone
and then aquaplaned on a runway that was affected by water following very
heavy rain. The crew omitted to use either full or idle reverse thrust
during the landing. The aircraft was still moving at 88 kts (163 km/h)
at the end of the runway and stopped 220 m later in soft turf with its
nose on the airport perimeter road. A precautionary evacuation was made
using emergency escape slides about 20 minutes later.
Although the flight crew and cabin
crew made a number of errors, many of these were linked to deficiencies
in Qantas's operational procedures, training and management processes.
CASA's regulations covering contaminated runways and emergency procedures
were also found to be deficient, as was its surveillance of airline flight
operations. Qantas and CASA either have made, or are in the process of
making, significant changes in the areas where deficiencies were identified
including the development by CASA of a systems-based surveillance audit
approach.
"This investigation is one of the most
comprehensive and exhaustive ever conducted by the ATSB (or its predecessor
the Bureau of Air Safety Investigation). I believe that the ATSB investigation,
and the safety enhancements made following the accident, constitute a
major contribution to aviation safety in Australia," Mr Bills said
Qantas Accepts Blame For 1999 Bangkok 747 Crash
Apr 25, 2001
An Australian Transport Safety Bureau (ATSB) report into the 1999
crash of a Qantas Boeing 747-400 at Bangkok's Don Muang airport criticises
Qantas for not having proper procedures in place to deal with landing
on wet runways and the pilots for not evacuating the 410 people on board
the aircraft immediately it had come to rest after skidding off the tarmac
and onto a golf course.
Qantas chief executive officer Geoff Dixon said the airline has accepted
the findings. "Qantas fully cooperated with the ATSB - we have taken action
on all the issues raised," Dixon said.
The report into the crash, in which no-one was killed but which caused
AUD$100 million (USD$50 million) of damage, reveals the accident could
have been averted if reverse thrust had been used on landing.
The ATSB report also cites poor surveillance by the Civil Aviation
Safety Authority (CASA) as a factor in the crash, which almost destroyed
the plane.
The London-bound plane, with 410 passengers and crew on board, attempted
an aborted landing, but the crew then reversed this decision.
Instead, it landed and fish-tailed 3 kilometres down the runway of Don
Muang Airport, ending up in a golf course.
The report says the crew was following company policy. "As
with other B747-400 pilots, the crew had not been provided with appropriate
procedures and training to properly evaluate the potential effect of the
weather conditions," the report says.
"In particular, they
were not sufficiently aware of the potential for aquaplaning and of the
importance of reverse thrust as a stopping force on water-affected runways.
That error was primarily due to the absence of appropriate company procedures
and training."
The report reveals that three years before
the accident, Qantas had introduced new landing procedures and pilot training
to reduce costs. It levels most of its criticism at Qantas's flight operations
branch, claiming it was "reactive
and informal rather than proactive and systematic."
CASA, too, comes in for severe criticism, the report pointing to "significant
latent failures". These included the
regulations covering wet-weather landings, and emergency procedures and
training.
The report also highlights "deficient"
surveillance of flight operations: "In
1998 and 1999, there were serious shortfalls in CASA's planned product-based
surveillance of Qantas flight operations."
ATSB executive director Kym Bills said: "It
was a wake-up call to Qantas, who may have been lulled into a false sense
of security by their very good safety record".
The crew also receive some criticism, with the report questioning the
first officer's flying and the decision of the captain not to abort the
landing.
It also criticises a decision by the crew not to immediately evacuate
the plane.
Reminder
Dal 1958 al 1972 furono
costruiti 556 aeromobili DC8 nelle varie versioni.
Alcune versioni portavano fino a 280 passeggeri stipati in poltrone con
un seating pitch ridottissimo.
Ad oggi risultano 82 aeromobili perduti per gravi incidenti, una percentuale
di circa il 15% di quelli costruiti. Questo aeromobile e molti dei piloti
che vi volarono hanno sostanzialmente pagato un tributo al progresso dell'aviazione
mettendo in luce fattori causali [prevalentemente human factor ed ergonomici]
dovuti al passaggio dagli aeromobili da trasporto dell'immediato dopoguerra
ai primi aeromobili con propulsione a getto.
Incidenti come quello di Atene dovrebbero restare nella memoria affinché
tale tributo non vada irrimediabilmente perduto.
Date: 08.10.1979
Operator: Swissair
Registration: HB-IDE
Year built: 1967
Crew: 0 fatalities/12 on board
Passengers: 14 fatalities/142 on board
Phase: Landing
Flight: Geneve-Athens
Remarks:
The aircraft touched down 740m past the displaced threshold of Runway
15L (2240m before the end), following an ILS approach. The DC-8 touched
down at a speed of 146kts, decellerated but overran the end of the runway.
The left wing and tail separated before the aircraft came to rest on a
public road some 80m beyond the end of the runway and 4m below airport
elevation. A fire broke out on the right side and spread quickly. The
DC-8 was called "Uri". PROBABLE CAUSE: "(1) The crew touched down the
aircraft too late, at a speed higher than normal after a non-stabilized
final approach. (2) The crew did not fully apply the braking systems (wheel
brakes and reverse thrust) particularly the wheel brakes after a touchdown
under known adverse conditions, so that it was not possible to stop the
aircraft at least before the end of the overrun area." Note: the member
of the Operations team of the Accident Invetigation Committee had a different
opinion from the rest of the Committee regarding the cause of the accident.
That is: "After a non-stabilized approach a too-late touchdown at an increased
speed was not realised by the crew. Contributing was the fact that (1)
the company's recommended technique concerning 'landing when braking action
is less then good' was not followed by the crew. (2) Wheel brake application
was not fully utilised by the crew at the proper stage of rolling after
touchdown. (3) Reverse thrust application was not fully utilised by the
crew at the proper stage of rolling after touchdown. "
