CONCORDE SST : Accident Report

12 - WRECKAGE AND IMPACT INFORMATION

12.1 The Runway

Various debris and marks were found on the runway after the accident (see drawing in appendix 3). They are identified in the following by the grid number of the concrete slab where they were found, the distances being measured in relation to the eastern end of the tarmac part of the runway (see section 10). Thus, for example, an element identified at Slab 180 level was found 1 950 m from the point of origin (600 + 180 x 7.5). Debris was also found under the aircraft's flight path.

Note: the point at which the brakes were released is located between 65 and 85 m from the beginning of the runway.

12.1.1 Water Deflector

Parts of the water deflector of the left main landing gear were found between Slabs 139 and 166, that is 1 642 to 1 845 m from the beginning of runway 26 right, more precisely at 139, 149, 151, 157 and 166. The parts found did not include metallic parts.

Part found at Slab 166 level: right part of the deflector

12.1.2 Pieces of Tyre

Pieces of tyre from the Concorde were found at slab levels 146, 152, 166, 180, 186 and 187. The parts found at Slab 152 level (a piece measuring 100 x 33 cm and weighing more than 4 kg) and that found at Slab 180 level fitted together. Visual inspection revealed a transverse cut about 32 centimetres long.

Piece of tyre at Slab 180 level Piece of tyre at Slab 152 level

12.1.3 Piece of Metal

Piece found at Slab 152 level

A strip of metal about 43 centimetres long, bent at one of its ends, was found on the runway shoulder at Slab 152 level. Its width varies from 29 to 34 mm and it has drilled holes, some containing rivets, similar to the Cherry aeronautical type. The holes are not at regular intervals.

On visual inspection, the piece appeared to be made of light alloy, coated on one side with epoxy primer (greenish) and on the other side with what appeared to be red aircraft mastic for hot sections (RTV 106). It did not appear to have been exposed to high temperature.

This piece was not identified as part of the Concorde.

12.1.4 Structural Element

A ribbed structural part measuring about 30 x 30 cm was found at Slab 160 level. It was white on the external side and dark on the ribbed side. It came from the aircraft¹s No. 5 fuel tank. It showed no signs of impact damage.
Part found at Slab 160 level

12.1.5 Brake Servo Valve Case

An alloy part, identified as the brake servo valve case, from the left main landing gear, was found at Slab 175 level. This part was sooted and had clearly been overheated. It had impact deformation.

Part found at Slab 175 level

12.1.6 Piece of Concrete and Signs of Explosion

Signs of an explosion and a piece of concrete torn from the runway were found at the Slab 181 level. The piece of concrete was about one centimetre thick, 10 centimetres wide and 25 to 30 centimetres long. Found intact, it was later broken in two.

12.1.7 Lighting

The runway edge light at the Slab 293 level (about 2 800 m from the origin) was broken and small pieces of the light were found nearby. Ground marks showed that this light was broken by the Concorde¹s left main landing gear.

12.1.8 Tyre tracks

Irregular marks made by the left landing gear were noted up to the broken light (around 2 800 metres).
After this point, the marks became intermittent then disappeared at about 2 830 m from the runway threshold.
From Slab 161 level to Slab 232 level, that is between 1 807 and 2 340 m, the mark of a flat tyre with an incomplete tread was observed.
This mark was parallel to the runway axis (at about 3.8 m) then diverged at about 2 200 metres.
When this mark disappeared at about 2 340 m, its displacement from the centreline was about 8 m. This corresponded to the right front tyre of the aircraft¹s left landing gear.

Mark left by the left truck and broken light

12.1.9 Soot Deposit

Traces of soot, produced by incomplete combustion of kerosene, were apparent on the runway 1 860 m onward from the origin (Slab 168). These were large and dense up to 2 300 m and then became less dense and rich in carbon up to taxiway S4, at 2 770 metres. The traces, which were on average 7 m wide, were initially centred on the damaged wheel ground mark and progressed to a position corresponding to the far left of the aircraft.

Slab 202

A further sooted area was apparent after taxiway S4 up to the broken edge light.

Slab 290

Between Slabs 310 and 340

The grass was burnt adjacent to the runway edge, between 2 902 and 3 165 metres. This area, also featuring soot deposits, indicated that there was an extensive flame after the aircraft became airborne.

12.2 Between Runway 26 Right and the Site of the Accident

In the 1 000 m after the end of the runway, along the extended centreline, the following elements were identified:

From 1 000 to 2 500 m after the end of the runway:

Burn marks on the ground were visible where certain items of debris were found, particularly where the tar had melted adjacent to items found on the roofs of buildings in the freight zone. A wheat field was damaged by fire 2 500 m from end of the runway.

Beyond this point, the following was noted:

Leading up to the crash site, many small pieces of metal, honeycomb components, pieces of riveted structure and parts of the rear fuselage, were found. Most of these parts show traces of fire and their distribution was continuous along the aircraft¹s track.

12.3 The Accident Site

12.3.1 Description of Site and Plan

The crash occurred south-west of Paris Charles de Gaulle airport at about 9 500 m from the threshold of runway 26R in a level area. The altitude of the area is 400 feet. The wreckage was at the intersection of the N17 and the D902 roads.

BEA/IGN/FLEXIMAGE image, Aerial photo of the accident area

The crash site was divided into a grid. The various areas were referenced to this grid.

Map showing aircraft wreckage distribution at the crash site

Aerial view showing grid

Examination of the site showed that the aircraft had struck the ground on heading 120° left, with little horizontal speed. After the impact, it broke and spread generally to the south, with the aircraft upright.

The wreckage was extensively burnt. Only the front parts of the aircraft, found mainly in areas C3, D4 and Z4 escaped the ground fire, together with a few pieces of the fuselage scattered over the site. Most of the wreckage, with the exception of the cockpit, remained within a rectangle measuring a hundred metres long by fifty metres wide (areas CB2, D3 and E3).

Signs of ground impact were found to the north of the site at the intersection of areas A and B. There was a row of trees about three metres high, oriented east to west, then a crater at the bottom of which was rear tank No. 11. Pieces of engine air intake were found half-buried at A3 and signs of ground impact were apparent at A3 and CB2-North. Wheel N° 6 was embedded in the ground.

Ground impact marks

At B3, an impact mark was visible in the asphalt. Forward parts of the aircraft were in a line embedded in the earth, including the front left door sill and a hinge from the aircraft¹s droop nose. Near these items of debris, the grass was sparse.

Aerial view showing location of the main parts

The hotel located at CB2-North was almost entirely flattened. The lower parts of the left and right main landing gears were close to the initial impact marks.

The outer part of the left wing, with the outer elevons still attached, was found melted on the ground. Nearby was the inner part of the wing with the left dry bay with engines 1 and 2 still attached. The rudder was found between these two parts. The fin was resting on the dry bay. The left inner elevon was found beneath the two engines, still linked to part of the wing (this assembly is normally located between the left powerplants and the fuselage). The engines were resting on a water tank 1.5 m in height. Many wing parts were found nearby, including the lower surfaces of tanks 6 and 10.

The left main landing gear leg, still connected to its side strut, was found at CB2-South. Examination of the strut's locking mechanism showed that the landing gear was down and locked at the time of impact.

In the western area of the CB2-South rectangle, part of the ground floor of the hotel was still standing. A large number of items of debris from the building were found in the eastern area.

At C3, a large number of parts belonging to the cockpit had impacted an electric power transformer. The pilots' seats, the throttle levers and the autopilot control unit were found at this point. The seven landing gear ground lock pins were found with their stowage bag.

Next to this there was a section of the fuselage in which it was possible to recognise the aisle between cockpit and cabin. From this wreckage the QAR and the main components of the flight crew instrument panels were extracted (description follows).

Nearby, the nose landing gear was found, extended.

The main components of the Concorde's structure were found at D3 and E3, along the axis of the wreckage scatter. The passenger cabin was identifiable from pieces of fuselage, together with a large number of items of debris from the hotel. The passenger seats and most of the victims were found in these areas. The hydraulic tanks normally located in the rear hold and the CVR were found at E3 and the radio altimeters installed in the forward hold were found at D3. The structures of the main landing gear wheel well were grouped together at the intersection of areas D3 and E3, near the landing gear legs.

The right dry bay with engines 3 and 4 still partially attached was found at D3, to the right of the passenger cabin. Nearby, a large number of pieces of the right wing were found, including the three PFCU's that control the right elevons. The left main landing gear attachment structure was found to the left of the passenger cabin.

The right main landing gear attachment structure and a melted piece of the right wing were found at E3, to the right of the passenger cabin.

Pieces of fuselage were found in the peripheral areas H and I and in Z2.

12.3.2 Instrument Indications

The emergency landing gear extension selector on the rear of the flight deck centre console was not selected. The following indications were noted on the instruments found on the central panel:

Engine speed indicators:

Engine 1 Engine 2 Engine 3 Engine 4
N1 Absent Absent 52 % 58 %
N2 28 % 4 % 80 % 85 %

Fuel Flow indicators: For engine 4, a (yellow) pre-set display showed 19.6 kg/h x 1000.

Engine 1 Engine 2 Engine 3 Engine 4
FF 0 Burnt Burnt Close to 0

EGT indicators:

Engine 1 Engine 2 Engine 3 Engine 4
EGT 580°C 220°C 600°C 600°C

Brake pressure indicator: 400 Psi left and 1,500 Psi right.

AJ indicators: unreadable, the needles were missing for engines 3 and 4.

On the FO instrument panel, the following items were noted:

Instrument panel

On the Captain's instrument panel, the following items were noted:

On the coaming the following items were noted:

On the overhead panel, the following items were noted:

	1	2
Auto stab	Unreadable	Pitch axis: "Off" Roll axis: unreadable Yaw axis: "Off"
Artificial feel	Blue circuit Pitch axis: "Off" Roll axis: unreadable Yaw axis: "Up"	Green circuit Pitch axis: "Off" Roll axis: "Off" Yaw axis: "Off"
Electric trim	"Off"	"Off"

The warning panel was destroyed, separated from the rest of the upper panel and most of the covers and bulbs were missing.

On the flight engineer's left panel, the following items were noted:

	Engine 1	Engine 2	Engine 3	Engine 4
P7 indicators	18 Psi	12 Psi	18 Psi	18 Psi

The rest of the right part of this panel was unreadable. The air intakes panel was not read at the site.

On the flight engineer's upper left panel, the following items were noted:

	Engine 1	Engine 2	Engine 3	Engine 4
secondary nozzle indicators	0°	15°	5°	broken

The pressurisation system indications featured on this panel were not read out at the site.

On the flight engineer's central upper panel (fuel and air conditioning), the following items were noted:

Tank 9

Tank 10

Tank 5A

Tank 7A

Also

- Standby Inlet Valves 5, 6 and 1 on "Open", 2 on "Shut"
- Standby Inlet Valves 3, 4, 10 and 7 on "Shut", 8 on "Open"
- Jettison tank switches 1 and 3 in intermediate position, 4 on "Open", 2 on "Shut"
- Master Jettison and Trim Pipe Drain switches unreadable

On the flight engineer's central panel (fuel), the following items were noted:

Tank 5

Tank 6

Tank 1

Tank 2

Tank 7

Tank 8

Tank 3

Tank 4

Tank 11

FQIP (Fuel Quantity Indicator Panel) had the following pre-setting indications:

On the flight engineer's right upper panel (electrical and hydraulic generation), the following items were noted:

Green Circuit

Yellow Circuit

Blue Circuit

Also

On the flight engineer's right side panel (electrical generation), which was heavily damaged and burnt, only the following items providing information were noted:

- transformer rectifier unit (TRU) ammeters: 1 burnt "0", 2 broken "0", 3 "30A", 4 broken "70A"
- TRU selectors: TR1 unreadable, TR2 on "Normal", TR3 on "Isol", TR4 selector missing
- Eng 1 & 4 and Eng 2 & 3 nozzle safety switches on "Normal" but damaged on impact
- fuel tank pressure: "0" (touching red index)

On the flight engineer's lower right panel, which was heavily damaged and burnt, the following items were noted:

12.3.3 Examination of Engines

Secondary exhaust nozzles

General view of engine no. 4 upper secondary exhaust nozzle

The upper secondary exhaust nozzles were still in place on engines 1, 2, 4 and separated from the nozzle structure on engine 3. The lower secondary exhaust nozzles were separated from the structure and three of them were found intact. The upper actuators from engines 2 and 4 were attached to the structure and to the nozzles. The lower actuators were found at the site with the exception of that of engine 3.

Primary exhaust nozzles

Engine no. 2 primary exhaust nozzles

The primary exhaust nozzle from engine 3 was separated from the structure of the secondary nozzle. The latter was torn away from the rest of the engine. The nozzles from engines 1, 2 and 4 were in place but flattened by the impact with the ground.

General findings

The primary and secondary nozzles showed no signs of overheat on any of the engines. Black marks were visible on the inner panels of the engine 1 nozzles. Traces of soot were also found on the upper right part of the structure of the engine 2 nozzles. No trace of damage caused by an uncontained engine burst was noted.

The position of engines 1 and 2 nozzles was about 21°, a position compatible with the takeoff phase or the shutdown of an engine. The position of the engines 3 and 4 nozzles was 0°.

Examination of engine no. 2 appears to indicate a negligible N1 before impact. The rotor of the LP compressor of engine no. 1 apparently made less than a quarter of a revolution after the impact before being stopped by the casing being crushed.

Engine no. 1 LP compressor

Engines 1 and 2 showed signs of damage (FOD) by a soft object on the LP compressor rotor blades. Engine 1 also showed signs of FOD by a hard object. The damage found on engines 3 and 4 showed that they hit the ground with an N1 much higher than that of engine no. 1.

None of the engines showed signs of any fire occurring before the crash.

12.3.4 Examination of Wheels and Tyres

Wheel number 1

The entire wheel was burnt. The tyre, although burnt, showed no abnormal absence of material before impact at the accident site. There was black powder, the residue of combustion, on the base of the wheel. No trace of fire prior to the crash was observed.

The two half rims appeared to be intact.

The brake pack was separated from the wheel, being found about two metres away in an area affected by fire. It was covered with a deposit of soot.

Wheel number 2

The tyre was damaged by fire. The two beads were not linked by the tread. The outer bead of the tyre was complete and almost intact. The inner bead was broken and the metal wires of the bead cores were exposed and broken at the same point, characteristic of overload bursting on impact. The wire's protective rubber was burnt.

The sides showed local ruptures oriented at about 45°, this being characteristic of lateral overload.

There was an abnormal lack of material at the site. The black material which is left after the rubber combustion that would have corresponded to the volume missing at the base of the tyre could not be found.

The two half rims seemed to be complete.

The wheel coloration was still blue, which seems to indicate that it had not suffered from fire prior to the crash.

The brake pack was in place on the wheel axle.

Wheel number 5

The tyre showed no abnormal lack of material. It had a static rupture characteristic of overload. The entire wheel appeared normal except for the part exposed to the ground fire where the tread had been superficially burnt. This wheel did not suffer from fire during flight.

The two half rims seemed to be complete.

The brake pack was in place in the wheel.

Wheel number 6

The tyre showed no abnormal lack of material. It had a static rupture characteristic of overload. The entire wheel had a normal appearance, without traces of burning.

The two half rims seemed to be complete.

The brake pack was in place in the wheel.

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