On 16 July 2016, an Airbus A321 (D-ASTP) being operated by Germania on a scheduled passenger flight from Dusseldorf to Fuerteventura as GMI 3700 made a go around from the runway after a mishandled initial touchdown at destination following an approach in day VMC. The subsequent landing was successful but the aircraft was later found to have made its return flight to Dusseldorf in an unsafe condition due to serious damage caused during the initial abandoned landing attempt and on arrival was grounded for replacement of parts of both main landing gear assemblies.
No information about the event was received by the Spanish Commission for the Investigation of Civil Aviation Accidents and Incidents (CIAIAC) until over six weeks after it had occurred and information on the seriousness of damage to the main landing gear was not received by the CIAIAC until almost four months after the event, at which point the event “was deemed to have been a Serious Incident” and a CIAIAC Investigation was opened.
Prior to CIAIAC awareness of the event and immediately after the decision was made by Germania to ground the aircraft in Düsseldorf so that it could be inspected, the DFDR was removed and sent to Airbus for download in order to “determine the seriousness of the hard landing and specify the inspection actions to be taken to determine the scope of the damage”. These data were eventually made available to the Investigation and showed that the first attempt at landing had involved main gear runway contact at 3.32g at a 1,000 fpm rate of descent. Relevant data on the CVR had been overwritten.
The two concerns of the Investigation once opened were to establish the facts of and context for the hard landing and to focus on the continued operation of an un-airworthy aircraft thereafter.
It was found that the 38 year-old Training Captain was an A320 TRI who had accumulated a total of 6,830 flying hours which included 2,678 hours on type. The 30 year-old First Officer, who was PF for the flight and undergoing supervised line training had accumulated a total of 325 flying hours which included 96 hours on type.
The unstabilised first approach and go around
It was established that the flight had been cleared for an ILS approach and landing on the 3,406 metre-long runway 01 at Fuerteventura in benign weather conditions - surface wind from 040° at 6 knots, with CAVOK and a surface temperature of 26°C. The aircraft was observed by TWR to go around from the runway and when this was confirmed by the Captain and he was asked for the reason he was reported to have responded that it was because of “de-stabilisation on short final and on final in the landing flight path”. The subsequent visual right hand circuit at 1,500 feet was completed without further event and culminated in a normal landing nine minutes later.
A combination of the DFDR data, the Captain’s statement and information provided by the Operator from their own internal investigation led to the following understanding of the sequence of events during the initial approach:
- It was the first time the Captain had flown with the trainee First Officer. He stated that “with almost 100 hours of flight experience”, he had “deemed him to be sufficiently proficient to be able to use fewer automatic flight systems”.
- The Captain stated that during the flight he had discussed the fact that his training experience had led him to conclude that most pilots on line training “were reticent and hesitant to use manual power/thrust” and had suggested flying the approach without the autopilot or auto-thrust. He added that the First Officer “had done this before and was confident and wanted to do it and was thankful for the opportunity”.
- When subsequently established on visual final with AP and A/T disconnected, the approach was initially relatively well flown but below 500 feet, the speed had begun to become too low at the same time as the achieved vertical profile went below the (displayed) ILS GS. At around 400 feet, the Captain advised the First Officer that he was “slightly below” the ILS GS. When the required corrective action was not sufficient, the Captain again advised that they were “slightly below the glideslope” but although this was corrected, thrust was not sufficiently increased at the same time.
- At around 120 feet agl, the Captain advised the First Officer to increase the thrust, which he did to 60% N1 by 60 feet but the First Officer then pushed his side stick forward and the aircraft pitched down from 2.8° to 1.1° in 2.5 seconds. As the pitch reduced below 1.8° at 35 feet agl, the First Officer pitched up slightly and at 20 feet - 1.6 seconds before touchdown - the Captain made sharp pitch-up command on his side stick (dual input) until touchdown at 1,100 fpm.
- The Captain stated that he had at about this time “realised that the aircraft was sinking very close to the ground” and that a go around was necessary but although he had “taken control and started a go-around”, it was impossible to avoid a hard runway contact. He stated that “everything happened very fast and close to the ground (and that) he was unable to describe the exact sequence of events”.
- During the initial runway contact, which occurred wings level but with the thrust recorded as still at 60%, a 2.24g loading was recorded increasing to a maximum of 3.32 g within ¼ second. Thrust was reduced to idle and after a further ¼ second, the aircraft began a bounce and thereafter, the recorded g loading began to reduce.
- The Captain, having fully taken control began to increase the pitch and 1.5 seconds after the initial touchdown, he “commanded maximum thrust”.
- After checking that the First Officer was "OK” and wanted to resume the role of PF, the Captain reported having passed control back to him on base leg and the First Officer then flew an ILS approach making use of all automatic systems including the auto-thrust to a normal landing.
The illustration below (not scaled) shows the point of the bounce as a vertical line and the change in forward airspeed, vertical speed, pitch and vertical acceleration before and afterwards.
FDR-sourced relative changes in altitude, IAS, thrust and g-load during the hard landing. [Reproduced from the Official Report]
The Investigation noted that after this event, Germania had “acknowledged that its Airbus crews are generally not well trained on manual approaches due to the routine practice of using automatic systems”. As a result of the event, flying manually with manual thrust on visual approaches during line training flights was prohibited pending the formulation of “requirements, conditions and restrictions for flying manually on visual approaches” during such flights. The Company also stated that “new procedures will be defined and proposed for the Flight Manual involving manual flight/manual thrust and work overload when not using automatic systems”.
Damage to the aircraft
When the aircraft was eventually given a proper inspection by engineers, it was found that the damage / load limit exceedances caused by the hard landing were confined to the main landing gear and required, before further flight, replacement of the left main gear assembly and shock absorber and the right main gear shock absorber.
How the aircraft came to depart afterwards when not airworthy
All Airbus A320 family aircraft are fitted with a system which notifies the crew of a hard landing by generating a ‘LOAD 15’ Report. The crew stated that they did not see the ECAM message ‘G LOAD’ which would have been displayed if the excessive load had continued for more than 2 seconds and this corresponded to the fact that the peak load had in this case lasted less than 1 second. The Captain also stated that the ACARS printer did not generate a ‘LOAD 15’ message “which he would have expected” for any excessive loading but that to make sure, he had called the Company Maintenance Operations Centre (MOC) who then checked their computer. They confirmed that they had received one but “could not correctly interpret or decipher it” and could not respond usefully to the Captain’s request for help in finding it in the onboard avionics systems. No local maintenance support was available at Fuertaventura and, after a further call to the MOC in which they did not raise any objection to continued operation of the aircraft, the Captain decided, after conducting a careful external inspection during which he found nothing untoward, that he should fly the aircraft back to Dusseldorf. During this flight, the MOC personnel realised that the ‘Load 15’ Report they had received showed that a peak load well in excess of what was allowable had been registered and that the aircraft would have to be grounded on arrival, which it then was.
The Cause of the Serious Incident was formally stated as “the performance of an unstabilised final approach, resulting from a decrease in airspeed and falling below the glide slope, as well as from the late decision to execute a go-around”.
A Contributory Factor was also identified as “the fact that the manoeuvre was performed without (use being made of) automatic systems to control the airplane’s attitude/flight path or thrust”.
It was also concluded that “the decision made after the event to continue to operate the airplane with passengers was risky and unsafe and resulted from an incorrect assessment of the seriousness of the hard landing”.
One Safety Recommendation was made as a result of the Investigation as follows:
- that air transport operator Germania establish a training program for its Maintenance Operations Centre (MOC) personnel that ensures they provide correct support so that safe decisions are made in every aerodrome at all hours of operation. [REC 55/17]
The Final Report was approved on 28 June 2017 and subsequently made available in English translation.