18th of August 2007, Blog #510
An Avro RJ100 was operating a scheduled flight from Zürich-Kloten Airport (Switzerland) to London City Airport (United Kingdom) on this day in 2007. A crew of 5 (2 pilots & 3 cabin crew) and 88 passengers were onboard the aircraft. the captain was the pilot flying (PF) while the copilot was the pilot monitoring (PM) for the flight. This was in accordance with the airline's procedures for landing at London City.
The damaged lower aft fuselage (©AAIB)
After an uneventful flight, the aircraft was vectored by ATC for an ILS approach to runway 28.
The weather reported by the ATIS was;
Surface wind from 190º at 11 kt
Visibility 16 km
Scattered cloud at 2,200 ft, broken cloud at 4,500 ft
QNH 1012 Mb
The landing weight was calculated to be 37.8 ton, resulting in a Vref of 119 knots for a flap 33º landing. At an altitude of 3000 feet the localiser was intercepted, a short while later, at 1300 feet the autopilot was disconnected. ATC provided the crew with the latest surface wind information just before the aircraft landed, wind 190º at 10 knots. During the approach the aircraft was ~4 knots below Vref.
As the EGPWS radio altitude call outs were made during the approach, between the 50 and 30 feet call outs the crew sensed an increase in vertical speed. They sense the aircraft was dropping. To correct this the PF pulled back on the control column, to prevent a hard landing. This cause the pitch of the aircraft to increase to 9.3º, which was also the attitude at touchdown.
This caused the rear fuselage to strike the runway before the mainwheels touched down. The acceleration recorded was 2.3g. None of the crew were aware they had a tailstrike on landing, although the carbon crew member in te rear of the cabin reported hearing a loud noise on touchdown.
The aircraft awaiting repairs (© Phil Newson)
Damage to the aircraft was extensive, significant structural damage was found to the lower fuselage in the area of the aft cargo hold, over a length of nearly 4 meters. The tail scrape indicator had almost worn away and a lengthwise crack was found in the structure. Almost all the frames and stringers in the area were damage to some degree.
The damaged area indicated in pink (© AAIB)
The landing incident was investigated by the Air Accident Investigation Branch (AAIB). The analysis of the incident in the report states;
"During the approach, at 50 ft and 35 ft, the aircraft was some 4 kt below target speed. At this point, the thrust levers were retarded to idle and the recorded groundspeed reduced, without a corresponding decrease in the airspeed, indicating a loss of headwind or an increased tailwind component. (Flight Data Recorder Data revealed that at ~50 feet altitude the headwind component changed to a slight tailwind component) The aircraft was already in a low energy state; then thrust was reduced and this reduction, and the loss of headwind component, both made the situation worse.
A combination of these factors reduced the energy of the aircraft, which was felt as a ‘sink’ by the pilots, and the commander responded by pulling back to prevent a hard landing. It was this, probably instinctive, pull back on the column that caused the pitch attitude to increase to 9.3° at the point of touchdown."
The AAIB investigation report, on which this blog is based, is available by clicking on the .pdf file below;