This category contains articles on particular Accidents and Incidents. The severity of the actual outcome is not the primary qualification for inclusion. Instead, each event has been included because the investigation findings were considered to be illustrative of safety issues which it would be especially useful to make more widely available. The information contained in each summary article on an individual accident or incident is derived from the published Official Investigation Reports. Content in this category comes from Skybrary, ICAO and wikipedia among other sources and is used with permission.
AGC = Air Ground Communications (including Call Sign Confusion), AI = Airspace Infringement, AW = Airworthiness, BS = Bird Strike, CFIT = Controlled Flight into Terrain, FIRE = Fire (includes post crash fore and non fire source fumes), GND = Ground Operations, HF = Human Factors, LB = Level Bust, LOC= Loss of Control, LOS = Loss of Separation, RE = Runway Excursion, RI = Runway Incursion, WAKE = Wake Turbulence, WX = Weather.
Lesson created by Michael Egerton for Aviation English Asia Ltd
- You will be able to understand, pronounce, and use the words in the vocabulary list below.
- You will develop your vocabulary and the use of the suffix -ity
- You will be able to demonstrate comprehension of the passage by answering questions which require basic understanding and interpretation of the content.
- You will be able to identify contrasts in sentences from the text.
- You will be able to distinguish JH/CH sounds
- clearance 2. collision 3. incomplete 4. intermediate 5. opposite 6. concluded 7. operated 8. collided 9. occurred 10. depart 11. remain 12. scheduled 13. advised 14. landing 15. warnings
Pronunciation Practice: JH
- Introduce key phoneme with minimal pairs.
- Model and emphasize pronunciation.
- Individual and choral repetition.
Students will review the usage of and then identify contrasts in sentences from the text.
On 3 August 2017, a Boeing 737-900ER (PK-LJZ) being operated by Lion Air on a scheduled domestic passenger flight from Banda Aceh to Medan as JT197 touched down on runway 23 at destination in normal day visibility, and shortly after, collided with an ATR 72-500 being operated by Wings Airlines on a scheduled domestic passenger flight from Medan to Meulaboh as IW1252. Both aircraft sustained substantial damage but none of the 223 occupants were injured and both aircraft were taxied clear of the runway. ATC were advised of resultant debris on the runway but allowed the runway to remain in use until other aircraft subsequently using it had also reported the presence of debris after which it was closed.
Give a visual impression of the photographs below
Directions: Practice by saying the word pairs and example sentences, then speak the words from this text.
Word Pairsjoke-choke, juice-choose, jewel-chew, jill-chill, jeep-cheap
Example sentence: John joined Julie in June.
Examples from this text: Scheduled - Generally - Acknowledged - Encouraged - Challenged - Procedure -
Directions: Read the following passage carefully.
On 3 August 2017, a Boeing 737-900ER landing at Medan was in wing-to-wing collision as it touched down with an ATR 72-500 which had entered the same runway to depart at an intermediate point. Substantial damage was caused but both aircraft could be taxied clear. The Investigation concluded that the ATR 72 had entered the runway at an opposite direction without clearance after its incomplete readback had gone unchallenged by ATC. Controllers appeared not to have realized that a collision had occurred despite warnings of runway debris and the runway was not closed until other aircraft also reported debris.
An Investigation was carried out by the Indonesian National Transportation Safety Committee (NTSC) - the Komite Nasional Keselamatan Transportasi (KNKT). Data from the FDR and 2 hour CVRs of both aircraft were successfully downloaded and used to support the Investigation. ATC recorded data including from the TWR cab CCTV were also available.
The 45 year-old Captain of the 737, who had been PF at the time of the accident, was recorded by the Investigation as having 8,200 hours total flying experience which included 2,296 on type. The 23 year-old First Officer on the 737 was recorded as having 500 hours total flying experience, all of which were on type. The 59 year-old Captain of the ATR72, who had been PF at the time of the accident, was recorded by the Investigation as having 13,006 hours total flying experience of which 624 hours were on type. The 23 year-old First Officer of the ATR 72 was recorded as having 263 hours total flying experience of which 109 hours were on type. A third "observer pilot" was occupying the supernumerary seat in the ATR 72 flight deck.
Three controllers were in position at Medan Aerodrome Control at the time of the collision, a 34 year-old Supervisor employed there since 2014, a 24 year-old TWR controller employed there since 2017 and a 23 year-old GND controller employed there since 2016.
The departure of the ATR 72 was slightly delayed because of a problem with passenger baggage handling. On request, the GND controller issued a clearance to taxi from the apron via taxiways 'U', 'T', 'B' and 'C' to the full length holding point for runway 23 on taxiway 'C' (see the aerodrome layout illustration below). Whilst the aircraft was still with GND, the 737 had called TWR to report on the ILS LOC for runway 23 and had been cleared to land. Almost immediately after this exchange had been completed, the GND controller transferred the ATR 72 to TWR with the instruction to continue and hold short of runway 23. On checking in with TWR, the ATR 72 crew requested takeoff from the taxiway D intersection, which was an RET for runway exits in the opposite 05 direction, in order to expedite their departure following the delay at the gate and this was approved as permitted by ATC procedures.
Whilst the ATR 72 crew were actioning their ‘Before Takeoff’ Checklist, its Captain advised the TWR controller that they were approaching runway 23 but when the controller responded by asking if they were ready for an immediate departure, no reply was received. He asked the same question again and this time the Captain confirmed that they were - although at this point, the pre-takeoff ‘cabin secure’ report had not been received from the cabin crew.
TWR then issued a conditional clearance to line up behind the Lion Air on short final once it had passed and also advised an amendment to the Departure Clearance to route direct to destination after takeoff. Only the amendment to the Departure Clearance was read back - by the First Officer - and this significantly incomplete read back was acknowledged without comment by the TWR controller just as the 737 was passing 500 feet agl on final. Another aircraft then reported on final approach to runway 23 and was instructed to continue with the advice that there was traffic to depart ahead but no mention that they were No 2 to land. CVR data showed that the ATR72 Captain was becoming concerned at the absence of a ‘cabin secure’ report and after monitoring the Cabin Crew PA until completion, the First Officer instructed the cabin crew to take their seats for takeoff without further reference to the Captain. At this time, the 737 was passing 200 feet.
As the 737 passed 40 feet agl, the 737 First Officer alerted the Captain to the presence of an aircraft close to the runway and after no response repeated this at 10 feet agl. Two seconds after main gear touchdown, the First Officer advised the Captain that the aircraft previously seen was now entering the runway which was acknowledged. Four seconds later, the sound of impact was recorded on the CVR of both aircraft.
The first transmissions after the collision came from the 737 Captain who was unable to get any meaningful response from the TWR and after declaring a PAN without any detail, was instructed to vacate the runway via RET taxiway ’G’ towards the end of the runway. The TWR controller then instructed the next aircraft on approach to discontinue it and approved the request from its crew to orbit left. This was followed by an instruction to the 737 to contact GND where the controller instructed the aircraft to taxi to Parking Bay 31. Whilst taxiing in, the 737 Captain and First Officer confirmed that they had both heard the ATR72 being told to line up after they had landed. They also advised ATC that debris hazardous to other aircraft was likely to be on the runway and repeated this two minutes later after suspecting that the controller who acknowledged the first call had taken no action.
The ATR 72 crew, having mutually confirmed their belief that they had been cleared for an immediate takeoff and observing the significant damage to their aircraft, then contacted TWR and were told to ‘Standby’ whilst the Tower Supervisor, who had taken over the TWR controller position, instructed the 737 to contact GND. They were then given a further amendment to their Departure Clearance to which they responded they were “unable to depart” and were told to “hold on the runway”. One minute and 20 seconds after this, the Tower Supervisor issued a takeoff clearance to the ATR 72 to which its crew again stated that they were unable to depart and added that they needed to return to the apron for damage to be inspected. This time clearance to exit the runway via taxiway ‘E’ and then contact GND was given.
The ATC Supervisor who had taken over the TWR position appeared not to have understood that a collision had occurred despite being told of debris on the runway and having been able to observe two damaged aircraft taxing to the apron not far from the TWR cabin. Another aircraft waiting for a full length runway 23 departure on taxiway ‘C’ advised its position and that it would remain clear of the runway to TWR but after initially being told to standby, it was then instructed to enter and line up. Several aircraft were subsequently permitted to land on the debris-contaminated runway before a runway inspection had been performed which was not until 30 minutes after the collision had occurred. Recorded events immediately following the collision do not make any mention of the airport RFFS being advised of or otherwise aware of it having occurred or attending either the scene or the two aircraft during or after their taxi to the apron after the collision.
It was noted that the weather conditions at the time of the collision were good and the only relevant feature was that the variable easterly wind may have created a small tailwind component for traffic using runway 23. Although the 737 was carrying out an ILS approach, the lowest cloud over the aerodrome throughout the period was recorded as 1800 feet.
Damage to the aircraft
The damage to the two aircraft was indicative of the outer left wing of the 737 having cut off the outer right wing of the ATR 72 and part of the detached wing had then penetrated the forward right fuselage of the ATR in the vicinity of the flight deck. Approximately 3.4 metres of the outer left wing leading edge of the 737 was damaged as was approximately 3.4 x 0.4 metres of slat number 1 on this wing, with a piece of this of approximate size 65 cm × 40 cm becoming detached and falling onto the runway. Approximately 2.8 metres of the outer right wing of the ATR 72 was detached from the aircraft with most of it falling onto the runway but a small part was swept forward and penetrated the forward right fuselage below and just forward of the flight deck.
Most of the significant detached debris from the two aircraft was found on the right hand side of the runway 23 centreline. It was noted that the 3750 metre-long runway was 60 metres wide and that the combined wingspan of the 737 (35.79 metres) and the ATR72 (27.05 metres) was slightly greater than the width of the runway. However, there was no evidence that a runway excursion had occurred.
Findings from the assembled evidence
A number of issues were identified by the Investigation in a review of the assembled evidence. These included, in summary, the following:
ATR 72 Crew Traffic Awareness
The ATR 72 crew were unaware that the 737 had been cleared to land because they were still on the GND frequency when this clearance was given. The acceptance by ATC of the ATR 72 request to enter the departure runway at taxiway ‘D’, an RET for aircraft exiting runway 05, meant that the crew could not easily check that the final approach was clear visually before entering the runway. The Investigation could also not find any procedure requiring ATC to issue a caution to aircraft entering a departure runway using an RET primarily intended for traffic exiting in the opposite direction, especially when a departing aircraft is subject to a conditional clearance to enter the runway after a landing aircraft.
The effects of the delay to the ATR 72
As well as requesting departure from the ‘D’ RET, the Captain of the ATR 72 also advised TWR that his aircraft was ready for departure whilst it was still taxiing out even though the cabin crew were still some way from completing their pre takeoff duties. Both actions might be taken as an indication that he wished to expedite the departure because of delay to the flight leaving the gate.
737 Crew Traffic Awareness
The 737 crew heard the ATR 72 crew confirm that they could accept an immediate departure and on hearing this, the Captain had asked the First Officer to remind TWR that they were on short final. However, he cancelled this request when they heard that the clearance for the ATR 72 was to enter runway after they had landed.
Misunderstanding of the conditional clearance by the ATR crew
The conditional clearance to the ATR 72 to line up behind the landing aircraft was combined with an amended departure clearance and was delivered at a rate of speech faster than the recommendations given in the ICAO Manual of Radiotelephony Doc 9432. It was also issued without confirmation as to whether the crew were aware of the 737 on short final to land which was not in accordance with State regulatory requirements. The ATR 72 First Officer, who had very little experience as a pilot, was unable to receive all the information of the clearance and therefore read back only the its last sentence about the change to the departure clearance. This significantly incomplete read back was not challenged by the controller who “assumed that the pilot had acknowledged the clearance properly and considered that immediate action to correct the discrepancies in the pilot read back was unnecessary”. It was also noted that the ATR 72 crew would have heard the TWR controller advising another aircraft behind the 737 on short final that there was an aircraft (the ATR 72) to depart ahead of their landing. This call was intended to make the other arriving aircraft crew aware that there would be a departure between the landing 737 and their own subsequent landing, but it was considered that it might also have encouraged the ATR 72 crew to believe that they were number one in the sequence since - as noted - they were unaware that the 737 was ahead of the other aircraft and had been cleared to land.
Use of conditional clearances
It was noted that the procedure for issue of conditional clearances at Medan did not describe in detail the content of the corresponding State regulatory requirements and referred only generally to ICAO PANS-ATM Doc 4444 for examples of the phraseology and detailed the requirements for conditional clearances. Although the TWR controller on duty had been trained in the use of conditional clearances when studying to become a controller in Aviation College in 2015, there was no evidence that the use of conditional clearances had been the subject of any training since this time.
Monitoring of traffic by ATC
The applicable requirements for aerodrome/tower controllers include maintaining a continuous watch on all flight operations on and in the vicinity of an aerodrome. The movement of the ATR 72 contrary to its clearance was not monitored by the controller due to his other controlling activities and his assumption that the ATR 72 had satisfactorily acknowledged the clearance to line up only after 737 had landed.
Actions open to the 737 crew on observing the incursion
The 737 was passing 40 feet agl when the First Officer warned the Captain that the ATR 72 had crossed the Holding Point. The distance between the two aircraft at this time was estimated as just under 650 metres. Taking into account an expected height loss shortly after a go-around is initiated, a go around commenced at this time would most likely not have avoided the collision and indeed may well have resulted in more severe circumstances. Instead, the 737 Captain responded to the incursion by turning his aircraft 2° to the right three seconds after touchdown and whilst a wing-to-wing collision was unavoidable, this action to deviate to the right of the runway centreline had clearly reduced the severity of the collision.
ATC response to the collision
The location of the collision was in the 11 o’clock relative direction from the TWR building and the controller may have been unable to clearly observe what happened because the impact point was on the far side of the ATR 72. However, ATC were told that there was debris on runway by the 737 crew and by another departure aircraft crew and the crew of an aircraft that was subsequently permitted to land on the runway. Applicable ATC procedures required that if there was any doubt about the safety of any part of the movement area, the Airport Runway and Accessibility Unit must be asked to inspect that area and ATC must suspend use of the area until the inspection result indicates that the relevant part of the movement area is safe for operation especially if Foreign Object Debris (FOD) is suspected as a result of “unusual aircraft operation”.
Controller training issues
The last simulation of the handling of “unusual aircraft operations” for the Tower supervisor on duty was conducted in 2005 and for the Tower controller on duty it was conducted during their Aviation College studies to become a controller in 2015. The last performance check at the Medan Unit did not discuss unusual conditions or conditional clearance requirements. It was considered that information stored in the memory for long periods without use or rehearsal was very likely to be forgotten. It was also noted that serial inappropriate use conditional clearances over time without correction might well have led the controller to believe that his procedure was correct.
The Contributory Factors which facilitated the collision were formally documented as “misunderstanding of the communication of a conditional clearance to enter runway by the ATR 72 pilots who were not aware that the 737 had received a landing clearance and the fact that ATC did not notice the ATR 72 entering the runway”.
Directions: Read the following questions and answer each to the best of your ability.
- If you could interview the person responsible for this incident what two questions would you want to ask? Explain why each question is important.
- What connections can you make between the incident and your personal experiences?
- What lessons can be learned from this incident?
Identify 3 important supporting details that contribute to the main idea of the passage.
Identify 2 details that are not very important to the main idea of the passage.
Write 1 brief paragraph summarizing the main idea of the passage. Use the important details to support your discussion of the main idea.
Focus on Grammar
When we show the difference between two things, we contrast describes how things are different.
One word we use to contrast two things is "but". For example: "Bob likes dogs but Mary likes cats." shows the difference between what Bob likes and what Mary likes. Other ways to show difference include "however" and "even though".
What things are contrasted in the sentence(s) below?
Directions: Identify how the contrasts are used in the sentence(s) below
- However, there was no evidence that a runway excursion had occurred.
- Substantial damage was caused but both aircraft could be taxied clear.
- However, he cancelled this request when they heard that the clearance for the ATR 72 was to enter runway after they had landed
- Although the 737 was carrying out an ILS approach, the lowest cloud over the aerodrome throughout the period was recorded as 1800 feet.
Word Roots & Stems
Rule: The suffix ity adds "quality" or "state" to the meaning a word. For example, a celebrity is a person who is celebrated, and eternity is the state of being eternal.
Directions: Identify the word that ends with -ity in each sentence and write it on the line.
- Applicable ATC procedures required that if there was any doubt about the safety of any part of the movement area , the Airport Runway and Accessibility Unit must be asked to inspect that area and ATC must suspend use of the area until the inspection result indicates that the relevant part of the movement area is safe for operation especially if Foreign Object Debris ( FOD ) is suspected as
- Instead, the 737 Captain responded to the incursion by turning his aircraft 2 ° to the right three seconds after touchdown and whilst a wing-to - wing collision was unavoidable , this action to deviate to the right of the runway centreline had clearly reduced the severity of the collision.
- Instead, the 737 Captain responded to the incursion by turning his aircraft 2 ° to the right three seconds after touchdown and whilst a wing-to - wing collision was unavoidable , this action to deviate to the right of the runway centreline had clearly reduced the severity of the collision.
Directions: Fill in the blanks below, just as in the models.
(eternal - al) + ity
If you live for an eternity, you never die.
popular + ity
The movie was made for children, so its popularity with adults was surprising.
FILL IN THE BLANK
Directions: Use the word bank to identify the word that best completes the sentence.
- "the pilot managed to _______________ the aeroplane safely"
- The plane will _______________ at 10:00.
- She compared prices and _______________ the cheaper one was good enough.
- The doctor _______________ me for a 3:00 appointment.
- He _______________ a small business.
- His hair _______________ed black until he was 60.
- There is a _______________ to drive carefully near the school.
- Hot is the _______________ of cold.
- With a telescope, you can see where meteors and asteroids _______________ with the moon.
- There was a _______________ between two cars. Thankfully, no one was hurt.
- She _______________ him to get a haircut and a job.
- There are beginner, _______________, and advanced classes.
- The accident _______________ on a rainy night.
- The spy had _______________ to see the report.
- The house is _______________, we still need a roof.
Directions: Write the letter of word that matches the definition
_______ (air travel) cause to come to the ground
_______ To judge or decide after thinking.
_______ To add a meeting, appointment or event to one's personal schedule.
_______ To manage the working of something.
_______ To stay the same or in the same place.
_______ To tell about a danger.
_______ Completely different.
_______ To hit or crash into something.
_______ Violent contact.
_______ To offer an opinion as a good idea.
_______ Official permission.
_______ Not having everything that is needed.
Fill-in-the-blank Answer Key:
1)land 2)depart 3)concluded 4)scheduled 5)operates 6)remain 7)warning 8)opposite 9)collided 10)collision 11)advised 12)intermediate 13)occurred 14)clearance 15)incomplete
Matching Answer Key:
#aviationenglish #AviationEnglishAsia #IcaoEnglishTest #selfstudy #AEROSTAframework
On 27 October 2017, an aircraft returned to Auckland after advice from ATC that the right engine may have been affected by ingestion of FOD during engine start - a clipboard and paper left just inside the right hand engine by an employee of the airline’s ground handling contractor acting as the aircraft loading supervisor. The subsequent inspection found paper throughout the engine and minor damage to an engine fan blade and the fan case attrition liner. The Dispatcher overseeing the departure said she had seen the clipboard inside the engine but assumed it would be retrieved before departure.
An Investigation was carried out by the Australian Transport Safety Bureau (ATSB).
It was established that about 10 minutes prior to the eventual departure of the aircraft from its parking gate, the employee of the airline’s contracted ground handling provider tasked with loading the aircraft hold had put the last container onto the aircraft and was “organising his paperwork”. As it was raining, he reported having decided to put the clipboard to which the paperwork was attached in the right engine to avoid it getting wet and being blown by the wind, intending to retrieve it later. He had then gone to the flight deck, given some paperwork to the flight crew and then proceeded to prepare for the imminent pushback.
During this time, the Dispatcher reported having cleared the ground and servicing equipment from the aircraft vicinity and carried out a ‘duty of care’ walk-around during which she had noticed the clipboard in the right engine but took no action as she assumed that the loading supervisor would return for it. The subsequent engine start was normal but as the aircraft began to taxi, the loading supervisor realised his clipboard and paperwork were missing and initially thought the Dispatcher had it. When this was found not to be the case, the ground crew returned to where the aircraft had been parked and found paper debris on the ground. They then asked their “operations area” to contact the departed aircraft flight crew. Twelve minutes after the leading hand had first realised he no longer knew where his clipboard was, the aircraft took off.
Soon after this, as the aircraft was climbing through FL 150 with no abnormal engine indications, a call was received from the Auckland APP controller asking the crew to contact the Auckland GND controller direct. The Captain, who had been PF, handed control to the First Officer, made the requested call and was told that the ground crew had lost their paperwork which had been placed in the engine inlet and that paper debris had been found on the apron where the aircraft had been after starting the engines. After making a call to the Company Engineer at Auckland and being told that a piece of sheared metal had been found in the vicinity, he decided to make a precautionary return and landed back after an hour airborne. An inspection of the engine by engineers found minor damage had been caused to one engine fan blade and to the fan case attrition liner.
In respect of the loading supervisor’s action, it was noted that ground staff would normally use a metal box on the pushback tractor’s loader for sheltering such paperwork in case of adverse weather but on this occasion, the pushback tractor had not yet arrived. The loading supervisor did state that he had not felt any pressure to rush the departure and the Dispatcher stated that she had not viewed the clipboard as a foreign object as it belonged to the loading supervisor and she had assumed that he would retrieve it later, prior to engine start-up. It was noted that “there was no guidance on how paperwork was to be prepared and managed by ground crew during adverse weather conditions”.
An internal investigation by the contracted ground handler, Aerocare, found that the Jetstar Airways “Operational Manual” detailed the Dispatcher’s responsibilities when conducting the ‘duty of care’ walk-around and provided details of the actions involved. Whilst there was no explicit requirement to check the engine cowlings/intakes for foreign objects, this Manual did require that all staff operating near an aircraft due to depart must be constantly on the lookout for abnormalities and any seen must be reported to the leading hand or the Supervisor before the departure of the aircraft.
In respect of the communications with flight crew, in this case after it was realised what had probably happened, it was noted that there was no documented procedure by which the ground crew could establish communications with a flight crew in the event of any non-normal or emergency situation, either before or after the aircraft had departed. Also in respect of communications, the Captain stated that he had had to make numerous calls to various agencies in order to obtain more information about the incident which had taken up considerable time. He also stated that “poor communications” had meant that he had been unable to contact the Company Maintenance Controller to discuss the engine’s status.
Safety Action taken by Jetstar Airways as a result of the event and known to the Investigation was recorded as the issue of an updated aircraft dispatch procedure, which included:
a specific warning about not placing items in the engine cowling improved detail around checks and responsibilities a section on emergency and non-normal procedures detailed methods for re-establishing communications between ground crew and flight crew such as visually gaining the attention of the flight or contacting them via radio.
The Final Report was published on 27 February 2018. No Safety Recommendations were made.
On 12 December 2015, a Boeing 737-800 (EI-DLR) being operated by Ryanair on a domestic passenger flight from Seville to Barcelona as FR6399 which had just begun disembarking its passengers in normal night visibility conditions via an air bridge connected to door 1L, was lifted off its nose landing gear to a height of approximately 2 metres still attached to the air bridge until the door failed and the aircraft nose gear dropped back to the apron. Two of the 76 persons on board sustained minor injuries. Damage was caused to both the aircraft 1L door and the air bridge.
Investigation A Serious Incident Investigation was carried out by the Spanish Commission for the Investigation of Accidents and Incidents (CIAIAC). The 30 year-old Captain was a Spanish national and had 7,400 hours total flying experience of which 6,200 hours were on type. The 24 year old First Officer was a Portuguese national and had 350 hours total flying experience of which 50 hours were on type.
It was noted that the event had occurred at gate 101 at Terminal 2, the older of the two terminals at Barcelona which is situated to the north of runway 25R. It was found that the air bridge at gate 101 had been installed in 1991 and its hydraulic system subsequently refurbished in 2001. Its screen and control panel were then renovated in 2005 and most recently, in June 2015, its translation and control system had been renovated as part of a larger programme of air bridge renovation being undertaken by a contractor to the Airport Operator AENA, the Spanish Airports and Air Navigation Authority.
It was established that after passenger disembarkation had started and over half of the 159 passengers on board on arrival had already left the aircraft, the air bridge attached to door 1L had begun to lift the front of the aircraft off the ground. An alarm sounded at the air bridge control console and when the cabin crew realised what was happening, "they stopped the disembarkation of the passengers and asked the people still on board to move towards the front of the aircraft to sit down anywhere, as the door was expected to collapse and the aircraft nose to fall". This then happened and the remaining passengers were subsequently disembarked through door 2L at the rear of the aircraft and taken to the terminal by bus. Two of the passengers reported sustaining minor injuries.
It was noted that since the elevation of the aircraft by the air bridge was gradual, and the aircraft had remained at the same height as the air bridge as this was happening, there had been no actual risk to the passengers who were disembarking when the elevation began. However, likelihood of the subsequent collapse of the aircraft door due to it carrying part of the weight of the aircraft had represented a risk to any unseated passengers which had been successfully mitigated by the prompt intervention of the cabin crew.
Functional testing of the air bridge found that it was not possible to reproduce or replicate the failure which had occurred but subsequent testing did show that the air bridge involved had a pre-existing intermittent fault in its hydraulic lifting circuit electrovalve which had randomly been blocking or freezing in an open position. Similar testing of other Terminal 2 air bridges, and in particular one which was of the exactly the same design as the one under investigation but which had not yet been renovated, found that there was a 1 second time limit on the activation of the elevation system hydraulic pressure which meant that any blockage of the controlling electrovalve would not be followed by continued uncontrolled lifting (or lowering). This finding led to the further finding that the renovation schedule had included the installation of a new control panel which included modified software for the control of air bridge elevation. This new control software was found to have increased the time limit for the activation of the elevation system hydraulic pressure from 1 second to 10 minutes but had not addressed the potential consequences of this change in the event of a malfunctioning system electrovalve. More generally, it was found that this oversight was a result of a failure to include in the renovation work programme any inspection of the condition of the control elements that were not being modiﬁed.
Given this dual origin of the malfunction, it could be deduced that the lifting of the air bridge had occurred when its self-levelling system had been activated by the slight change in aircraft height as passenger disembarkation proceeded which was detected by the "safety shoe" mounted between the L1 door and the height of the air bridge floor. The consequent input of hydraulic pressure was not then immediately stopped when the electrovalve (again) malfunctioned because of the increased time limit for availability of pressure in the circuit.
It was concluded that the specification of the programme to partially renovate the air bridges at Terminal 2 had been inadequate in that it had failed to consider the effect of the intended changes in the system on the parts of it that were not being renovated. It was noted that the renovation work was being undertaken by a Temporary Joint Venture - a "UTE" - consisting of Adelte Ports & Maritime and Luis Pares.
The Cause of the uncontrolled lifting of the air bridge was formally documented as "the combination of the failure of the electro-valve in the hydraulic elevation circuit and the modiﬁcation of the interval for the activation of the pump in this circuit of the self-levelling system that had been introduced during the (partial) renovation of the air bridge a few months earlier”.
Safety Action taken by Barcelona Airport as a result of the investigated occurrence was noted to have included "making sure that all air bridge hydraulic elevation pumps have a maximum activation interval of 1 second".
Two Safety Recommendations were made as a result of the Investigation as follows:
- that Barcelona Airport which is responsible for preventive maintenance before and after the process of renovating the air bridges should verify the good condition of the components that will remain in them after the modiﬁcation process. [80/16]
- that the Adelte-Luis Pares Joint Venture (the contractor undertaking the Terminal 2 air bridge renovation programme for Barcelona Airport) should assess all possible failure modes (which may arise in the modified air bridges as a result of the renovation work). [81/16]
The co-pilot of the Germanwings plane that crashed into the French Alps on Tuesday appeared to want to "destroy the plane", French officials have said.
There are now many serious questions raised by the French prosecutor about the safety protocols for the pilots and crew on board.