Description

On 2 March 2013, an Airbus A310-300 (CS-TGU) being operated by SATA International on a scheduled passenger flight from Lisbon to Ponta Delgada on São Miguel Island in the Azores initially bounced during a night landing on runway 30 in normal ground visibility and a significant tail strike then followed which resulted in substantial structure damage. The aircraft remained on the paved surface and was able to be taxied to the gate there were no injuries to the 125 occupants. However, the aircraft sustained significant structural damage.

Investigation

An Investigation was carried out by the GPIAA. It was found that as a result of the tail strike, the aircraft had sustained substantial structural damage which, in terms of ICAO Annex 13 (would have) "adversely affected the structural strength, performance and flight characteristics and required major repair and replacement of the affected components" and was beyond the level of repair covered by the Structural Repair Manual. After a temporary repair at Ponta Delgada, the aircraft was ferried out of service to Lisbon where permanent repairs were made.

The aircraft DFDR was successfully downloaded but the Cockpit Voice Recorder (CVR) CB was not tripped following the event and the relevant recording was consequently overwritten. The DAR was downloaded by the Operator and analysed as part of their Flight Data Monitoring programme.

It was concluded that the prevailing weather conditions had been "within the applicable operating limitations" and noted that the tailwind component for the landing had been 7 knots (maximum 10 knots) and the crosswind component 15 knots.

Both the 59 year old male Captain acting as (PM) and the 42 year old female First Officer (PF) were noted to have both had substantial experience on the aircraft type. It was considered unlikely that either pilot had been affected by fatigue.

It was found from examination of the recorded flight data that a stabilised approach had been flown and it was considered unlikely that either pilot had been affected by fatigue. The ELW of 103 tonnes was well within the MLW of 157 tonnes and it was noted that the runway 30 LDA was 2248 metres.

It was established that the descent and subsequent stable ILS approach to runway 30 was flown with the AP2 and the FD engaged. The applicable Vapp was 132Kts and the Reference Speed (Vref) was 126kt. At the applicable DH for the ILS approach of 241 feet, the AP was disengaged. Below 20 feet agl at a slightly high rate of descent, "there was a short flare followed by a light bounce (which registered 1.5g) with spoilers extended." In line with the "aircraft's natural aerodynamic tendency (there) was an increase in the pitch attitude in conjunction with a pulling force exerted on the control column" at a relatively high rotation rate of 3º/ second which continued until pitch attitude reached nearly 15º.This exceeded the 13.2º pitch angle at which a tailstrike would occur as the main landing gear shock absorbers became fully compressed during the second and final touchdown. During interview shortly after the event, both pilots were noted to have stated that the Captain had taken control of the aircraft just after the first bounce "in an attempt to correct profile by holding the nose up in order to avoid a hard nose wheel contact" but "this version of the event was contradicted in a later interview", when both pilots stated that Captain had taken over as PF when the AP was disengaged.

It was noted that the available option of installing modified PFDs with a Tail Strike Pitch Limit Indication during takeoff and landing had not been taken up. The Investigation noted that, in general, the risk of a tail strike during landing is increased as airspeed drops

Although no CVR recording was available, it was concluded on the basis of other evidence that "Crew Resource Management principles were not in evidence during the event." It was considered that the Captain’s selection of auto brakes to medium for the landing was likely to have significantly constrained the risk of a runway overrun.

It was noted that there was no published instrument approach procedure for the into- wind runway 12 and that the decision to land on runway 30 directly off an ILS approach with a tailwind had been made so as to avoid the need to make a circling approach at 850 feet agl over the sea at night.

It was determined that the Primary Cause of the incident was "inadequate recovery handling of a bounced firm landing (deviation from recommended flying pilot technique)".

It was further determined that there were eight Contributing Factors:

• High sink rate prior to and during flare;
• Aircraft firm landing followed by a light bounce;
• Crew momentary unawareness of aircraft position (in the air) and intentional column pulling action, trying to smooth nose wheel contact with ground;
• The presence of a tailwind component during the flare phase above recommended 10kts limits;
• Aircraft’s centre of gravity at a slightly backward position but this factor is of marginal contribution only;
• The decision to land on damp runway 30, with tailwind component marginal to the maximum permitted (10kts), instead of a circling to land to the actual runway (12) in use or the decision to discontinue the approach via a go-around procedure;
• A bounce recovery at night (with less visual references) characterized by taking place very close to the ground (less than 20 feet) hence allowing for a very short reaction time from the PF and little control effectiveness of the aircraft (throttle retarded and normal configuration to land);
• The existing take-off / landing certification standards, which were based on the attainment of the landing reference speeds, and flight crew training that was based on the monitoring of and response to those speeds, hindering crew to detect degraded landing speed and sink rate.

Four Safety Recommendations were made as a result of the Investigation as follows:

• that the Portuguese Civil Aviation Authority (INAC), issues a Circular of Aeronautical Information (CIA) defining the procedures to be adopted by the operators in order to ensure the rapid preservation of CVR (Cockpit Voice Recorder) and FDR (Flight Data Recorder) recordings after an accident or serious incident, in accordance with the obligations in EU-OPS n°859/2008 and European regulation n°996/2010 (article 13.3). [RS 01/2014]

• that NAV Portugal implements a RNAV approach to runway 12 at LPPD airport (Ponta Delgada) covering the various operationally relevant entry sectors and subsequently, [the text after this appears to be missing from the English language translation] [RS 02/2014]

• that SATA International and other operators of Ponta Delgada’s airport adequately certify, train and qualify their flight crew in RNAV approach flying and appropriately certify their aircraft (for such approaches) [RS 03/2014]

• that ANA - Aeroportos de Portugal (Ponta Delgada Airport Management) assess the adequacy of existing lighting equipment in identifying natural obstacles within the airport vicinity and in particular in the approach segment of runway 12 [RS 04/2014]

The Final Report was completed on 15 December 2014, approved by the GPIAA Director on 29 December 2014 and subsequently published in both Portuguese and an English translation.

Further Reading

• Loss of Control
• Tail Strike
• Landing Flare
• Energy Management during Approach
• Crew Resource Management (OGHFA BN)
• AIRBUS FOBN "Preventing Tailstrikes at Landing". Sep 2007.