A Boeing 737-800 suffered a hard landing accident following an unstabilized approach in turbulent weather conditions, according to a Portuguese investigation report.
On February 22, 2014, Travel Service Flight TVS4130, a Boeing 737-800, operated on a commercial passenger flight from Prague (Czech Republic), to Montego Bay (Jamaica) with an en route refueling stop at Terceira, Azores. The captain was Pilot Flying.
The en route part of the first leg was uneventful. Runway in use at Terceira-Lajes Airport was runway 15. There was a partially cloudy sky, good visibility, a strong surface wind from southwest (190° at 22 kts gusting to 32 kts), with direction variations between 160° and 230° and the air temperature was 15°C.
The commander reported that the visual approach to runway 15 seemed normal until 5 NM from touchdown. Winds were registered at a speed of up to 50 kts and there was severe turbulence along the entire approach.
Below 1000 feet the crew noticed effects of down-drafts and up-drafts, with huge variations in intensity until short final. The captain stated that he opted to maintain an angle of descent (G/S) above the recommended, due to severe turbulence and to ensure a safety margin. The entire approach was flown with Auto Thrust connected, for effective and accurate speed control.
The aircraft developed a high sink rate and lost speed instantly. This was counteracted by the captain with increasing power and attitude, in an attempt to stabilize the sink-rate.
Touchdown occurred with a high rate of descent and a short flare, resulting in an impact on the main landing gear of 3.52 G vertical acceleration, followed by a bounce.
A forward push of the control column by the pilot flying resulted in a pitch-down attitude of -1.9° with a second impact of 2.75 G vertical acceleration over the nose wheel causing substantial damage in that area of the aircraft fuselage.
An inspection revealed the existence of some folded braces in the interior structure of the nose wheel bay with some bent struts, cracks found in fuselage frames that had suffered structural damage from the vertical loads applied in the contact with the runway.
The Portuguese Civil Aviation Safety Investigation Authority (GPIAA) concluded their investigation in October 2015, establishing the following causes:
The flight crew did not comply with aircraft manufacturer procedures and company SOPs, which required a “go around” manoeuvre;
The accident was due to an excessive control column forward input, causing aircraft negative pitch attitude which led to a very high impact loading on the nose undercarriage, leading to the severe damage of braces in the interior structure of the nose wheel bay, struts and fuselage frames. This followed a chain of events, which contributed to the accident including the wind gusts, turbulence, decision to fly above ILS G/P, the use of the A/T without A/P and the decision to land from an unstabilized final approach.
The following were considered as contributing factors:
1. The aircraft approach was conducted under turbulent conditions;
2. The PF established an approach profile of one dot of scale above the nominal ILS G/S;
3. The PF did not disconnect the A/T after disengagement of the A/P;
4. Deviation from aircraft “stabilized approach” profile;
5. The PM did not provide the required call outs for the “stabilized approach” deviations.
- GPIAA Final Report (PDF)