Retired in SAN
Time to return to the saddle..
If this was already posted, I do
apologize
Uncontained Cargo Fire - UPS Flight 6
A few days ago, the General Civil Aviation Authority of the United
Arab Emirates has released its final report on the Boeing 747 which
crashed on the 3rd of September in 2010 after an uncontained cargo
fire.
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Uncontained Cargo Fire Leading to Loss of Control Inflight and
Uncontrolled Descent Into Terrain
The 326-page accident report is excellently written and deals with all
the issues involved with this tragic flight and an analysis of the
situation. Here is a summary of the main points.
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11:35 UPS Airlines Boeing 747-400AF, a two-crew four-engine wide-body
aircraft, arrives from Hong Kong on a scheduled cargo service.
The Flight Crew reported a failure with the PACK 1 air conditioner
during the flight. The ground engineer could not replicate the fault.
The PACKs provide preconditioned air to the pressurized fuselage. The
Boeing 747 has three PACKs.
14:51 The Boeing 747 departs as UPS Airlines Flight 6 as a scheduled
cargo flight to Cologne Bonn Airport. The First Officer is the Pilot
Flying and the Captain is the Pilot Not Flying. They depart on Runway
30R and fly north west over the southern Arabian Gulf.
The First Officer flew the aircraft manually to an altitude of 11,300
feet and then engaged the autopilot after receiving another PACK 1
fault. The flight crewreset PACK 1 which cleared the fault.
The aircraft continued to climb. Shortly before they reached their
cruising altitude of 32,000 feet, a fire warning bell sounded and the
master warning light illuminated. They had a fire on the forward main
deck. The Captain took control of the aircraft.
15:12:57 CAPT in cockpit: Fire, main deck forward. Alright, I’ll fly
the aircraft
15:13:07 CAPT in cockpit: I got the radio, go ahead and run [the checklist]
15:13:14 CAPT to ATC: Just got a fire indication on the main deck I
need to land ASAP
15:13:19 BAE-C: Doha at your ten o’clock and one hundred miles is that
close enough?
15:13:23 CAPT: how about we turn around and go back to Dubai, I’d like
to declare an emergency
15:13:27 BAE-C: UPS six make a right turn heading zero nine zero
descend to flight level two eight zero.
Doha was closer, they were about 180 miles from Dubai. However, it is
unlikely that the crew understood the extent of the fire.
The crew put on oxygen masks and worked their way through the
Fire/Smoke/Fumes checklist.
The fire suppression system automatically shut down PACK 2 and 3. The
flight crew manually turned the switches to OFF, in accordance with
their check list. In fire suppression mode, PACK 1 should have
continued to supply preconditioned air to the upper deck. This
provides positive air pressure to the cockpit to prevent smoke and
fumes from entering the cockpit area. However, at 15:15:21, PACK 1
stopped operating. This meant that no packs were operating and there
was no ventilation to the upper deck and flight deck. Smoke began to
enter the cockpit.
15:15:23 CAPT to ATC: I need a descent down to ten thousand right away sir.
It’s unclear why the Captain requested the descent, although it seems
to me he was probably reacting to the smoke and concerned about
available oxygen. However, this was not on his checklist, which stated
he should fly at 25,000 feet, the optimum altitude to prevent
combustion. His action did not support the firesuppression system
which was based on depressurisation and oxygen deprivation.
The uncontained cargo fire severely damaged the control cables, the
truss framesupporting the cables and the cable tension.
15:15:37 CAPT: alright. I’ve barely got control
15:15:38 F.O: I can’t hear you
15:15:41 CAPT: Alright
15:15:47 F.O: alright… find out what the hell’s goin on, I’ve barely
got control of the aircraft.
15:16:41 CAPT: I have no control of the aircraft.
15:15:43 F.O: okay… what?
15:16:47 CAPT: I have no pitch control of the aircraft
15:15:53 F.O: you don’t have control at all?
15:16:42 CAPT: I have no control of the aircraft.
15:16:47 CAPT: I have no pitch control of the aircraft.
They regained control of the elevator control system through the
autopilot. Meanwhile, the cockpit was filling with smoke. Within two
minutes, neither crew member could see the control panels or look out
of the cockpit.
15:16:57 CAPT: Pull the smoke handle.
Pulling the smoke handle might have caused a pressure differential,
drawing more smoke into the cockpit. The Captain contacted ATC to
report the situation and then spoke to the First Officer.
15:17:39 CAPT: Can you see anything?
15:17:40 F.O: No, I can’t see anything.
The flight crew attempted to input the Dubai Runway 12 left data into
the flight management computer, so that they could configure the
aircraft for an auto-flight/auto-land approach, but they couldn’t see
the FMC display for all the smoke. At that point, the Captain’s oxygen
supply failed.
15:19:56 CAPT: I’ve got no oxygen.
15:19:58 F.O: Okay
15:20:00 F.O: Keep working at it, you got it.
15:20:02 CAPT: I got no oxygen I can’t breathe.
15:20:04 F.O: okay okay.
15:20:06 F.O: what do you want me to get you?
15:20:08 CAPT: Oxygen.
15:20:11 F.O: Okay
15:20:12 CAPT: Get me oxygen.
15:20:12 F.O: hold on okay.
15:20:16 F.O: Are you okay?
15:20:17 CAPT: (I’m out of) oxygen.
15:20:19 F.O: I don’t know where to get it.
15:20:20 CAPT
15:20:21 F.O: Okay
15:20:21 CAPT:You fly (the aircraft)
A portable oxygen bottle was behind the Captain’s seat, next to the
left-hand observer’s seat, but neither crew member retrieved the
bottle. The Captain moved aft of the cockpit area, presumably to try
to find the supplementary oxygen. He removed his oxygen mask and smoke
goggles and said, “I cannot see.” That was the last recording which
included the Captain; he died as a result of carbon monoxide
inhalation.
Seven minutes had elapsed since the fire alarm had first sounded. The
First Officer was now Pilot Flying, with no support nor monitoring. A
nearby aircraft contacted him to relay information to Bahrain. The
First Officer established communication and attempted to cope with a
swiftly escalating task load, which left him no time to enquire after
the Captain.
15:25:42 PF: I would like immediate vectors to the nearest airport I’m
gonna need radar guidance I cannot see.
Based on his comments, the investigators believe that the pilot was
able to see heading, speed and altitude select windows. He could not
see the primary flight displays. He could not read the navigation
display. Thus he could set up flight configurations but he couldn’t
see the response. He also made numerous comments about not being able
to see outside and that the heat was increasing and his oxygen was
getting low.
He couldn’t see the radio either, so he couldn’t change frequency
although he was now out of range of the controller at BAE-C. The
controller asked aircraft to relay information to and from the Boeing.
Dubai ATC also transmitted several advisory messages to the flight on
local frequencies in hopes of getting a message to the Boeing,
including “any runway is available.” They turned on the lights for
Runway 30L.
A relay aircraft contacted the Pilot Flying and attempted to pass his
information on to Bahrain. The relay aircraft (identified as 751)
struggled to relay the information and get answers from Bahrain. The
relay system was of little use to the Pilot Flying who didn’t know his
own altitude or speed and needed immediate data.
15:29:59 PF: Okay Bahrain give me what is my current airspeed? [groundspeed]
15:30:07 PF: Current airspeed immediately immediately.
15:30:14 PF: What is my distance from Dubai International UPS er six
what is my distance we are on fire. it is getting very hot and we
cannot see.
15:30:22 RELAY AIRCRAFT: Okay I ask Bahrain understood and UPS six
request the distance from Dubai from now?
15:30:28 PF: Sir I need to speak directly to you I cannot be passed
along I need to speak directly to you. I am flying blind.
15:30:36 RELAY AIRCRAFT: Understood UPS six we are just changes to
another aircraft to be with Dubai to relay with you I ask again to
Bahrain Bahrain distance UPS six to Dubai?
The workload of the Pilot Flying was immense. He was communicating
through aircraft relays while he controlled the flight and attempted
to navigate to Dubai International, with no access to navigation
equipment and no possibility of looking out the window. He repeatedly
asked the relays for information on height, speed and direction to
plan his blind flight. There was no opportunity to finish the
checklist nor check on the Captain.
The options available to the pilot were limited. The aircraft was
seriously compromised but without primary instruments, so the First
Officer couldn’t see what was and wasn’t working. He couldn’t even
ditch the aircraft in the Arabian Gulf as he didn’t know his own
altitude and couldn’t see out the window.
The Boeing 747 approached Dubai travelling 350 knots at an altitude of
9,000 feet and descending.
The computed airspeed was 350 knots, at an altitude of 9,000 feet and
descending on a heading of 105° which was an interception heading for
the ILS at RWY12L. The FMC was tuned for RWY12L, the PF selected the
‘Approach’ push button on the Mode Control Panel [MCP] the aircraft
captures the Glide Slope (G/S). The AP did not transition into the
Localizer Mode while the Localizer was armed.
ATC at Dubai asked a relay aircraft to advise the Pilot Flying,
“You’re too fast and too high. Can you make a 360? Perform a 360 if
able.”
The First Officer responded simply with, “Negative, negative, negative.”
The Pilot Flying set the landing gear lever to down. This caused an
aural warning alarm: Landing Gear Disagree Caution.
15:38:20 PF: “I have no gear.”
The aircraft passed north of the aerodrome on a heading of 89° at a
speed of 320 knots, altitude 4200 feet and descending.
He had no landing gear. He was fast and high. The fire was still
burning and the cockpit was thick with smoke. He couldn’t see a thing.
And now he’d overflown the airport.
There was another airfield, Sharjah Airport, which was 10 nautical
miles to the left of the aircraft. The relay pilot asked if the Pilot
Flying could turn left onto a 10 mile final approach for Sharjah’s
runway 30.
19:38:37 PF: Sir, where are we? Where are we located?
19:38:39 RELAY AIRCRAFT: Are you able to do a left turn now, to
Sharjah? It’s ten miles away.
19:38:43 PF: Gimme a left turn, what heading?
The relay aircraft advised that SHJ was at 095° from the current
position at 10nm. The PF acknowledged the heading change to 095° for
SHJ.
However, the Pilot Flying selected 195°. The aircraft banked to the
right as the Flight Management Computer captured the heading change.
The aircraft entered a descending right-hand turn at an altitude of
4,000 feet. Then there were a number of pitch oscillations commanded
by the Pilot Flying as the elevator effectiveness decreased.
The aircraft was heading straight for Dubai Silicone Oasis, a large
urban community. I suppose the one good thing in this fiasco is that
it never made it that far.
15:40:15 RELAY AIRCRAFT: Okay Dubai field is three o’clock it’s at
your three o’clock and five miles
15:40:20 PF: What is my altitude, and my heading?
15:40:25 PF: My airspeed? [groundspeed]
The pitch control was ineffective. The control column was fully aft
but there was no corresponding elevator movement. The aircraft was out
of control.
15:41:33 The Ground Proximity Warning System sounds an alert: PULL UP
15:41:35 [data ends]
The Boeing crashed into a service road in the Nad Al Sheba military
base nine miles south of Dubai.
So what caused the fire to go so quickly out of control?
The cargo loaded in Hong Kong included a large amount of lithium
batteries distributed throughout the cargo decks. However, packing
slips and package details, showing that the cargo contained lithium
batteries and electronic devices packed with lithium batteries, were
not inspected until after the accident. At least three of the
shipments contained lithium ion batteries which are specified as a
hazard class 9 and should have been declared as hazardous cargo.
Lithium batteries have a history of thermal runaway and fire, are
unstable when damaged and can short circuit if exposed to
overcharging, the application of reverse polarity or exposure to high
temperature are all potential failure scenarios which can lead to
thermal runaway. Once a battery is in thermal runaway, it cannot be
extinguished with the types of extinguishing agent used on board
aircraft and the potential for ignition of adjacent combustible
material exists.
The investigators believe that a lithium battery or batteries went
into an “energetic failure characterized by thermal runaway” – in
other words a battery auto-ignited. This started a chain reaction,
igniting all the combustible material on the deck. The resulting
fast-burning blaze then ignited the adjacent cargo, which also
included lithium batteries. The remaining cargo then ignited and
continued in a sustained state of combustion, that is the
conflagration continued burning until the crash.
The single point of failure in this accident was the inability of the
cargo compartment liner to prevent the fire and smoke penetration of
the area above pallet locations in main deck fire zone 3.
This resulted in severe damage to the aircraft control and crew
survivability systems, resulting in numerous cascading failures.
As the cargo compartment liner failed, the thermal energy available
was immediately affecting the systems above the fire location: this
included the control assembly trusses, the oxygen system, the ECS
ducting and the habitable area above the fire in the supernumerary
compartment and in the cockpit.
The probable causes start with the fire developing in the palletized
cargo, which escalated rapidly into a catastrophic uncontained fire.
The cargo compartment liners failed. The heat from the fire caused the
malfunctions in the truss assemblies and control cables, disabling the
cable tension and elevator function. The heat also affected the
supplementary oxygen system, cutting off the Captain’s oxygen supply.
The volume of toxic smoke obscured the view of the primary flight
displays and the view outside the cockpit, exacerbated by the shutdown
of PACK 1. And finally, the fire detection itself did not give enough
time for the flight crew or the smoke suppression systems to react
before the fire was a conflagration.
A key consideration that the investigation puts forward is the useful
response time in the case of an on-board fire.
A study conducted by the Transportation Safety Board of Canada, in
which 15 in-flight fires between 1967 and 1998 were investigated,
revealed that the average elapsed time between the discovery of an
in-flight fire and the aircraft ditched, conducted a forced landing,
or crashed ranged between 5 and 35 minutes, average landing of the
aircraft is 17 minutes.
Two other B747 Freighter accidents caused by main deck cargo fires
have similar time of detection to time of loss of the aircraft time
frames, South African Airways Flight 295 was 19 minutes before loss of
contact and Asiana Airlines Flight 991 was eight minutes. Both
aircraft had cargo that ignited in the aft of the main deck cargo
compartment.
The accident aircraft in this case, was 28 minutes from the time of
detection until loss of control in flight. The cargo that ignited was
in the forward section of the main deck cargo compartment. The average
time is seventeen minutes. This should be factored into the fire
checklist that an immediate landing should be announced, planned,
organized and executed without delay.
These findings indicate that crews may have a limited time to complete
various checklist actions before an emergency landing needs to be
completed and the checklist guidance to initiate such a diversion
should be provided and should appear early in a checklist seque
