Loss of AS332L1 LN-OPG off Brønnøysund, Norway, 8 September 1997
Loss of AS332L1 LN-OPG off Brønnøysund, Norway, 8 September 1997 This accident and the loss of 12 lives off the coast of Norway in 1997 had far reaching consequences for the use and regulation of helicopter Health and Usage Monitoring Systems (HUMS). The Accident On 8 September 1997 at 06:00 local time, a Norwegian AS332L1, registered LN-OPG, departed from Brønnøysund, just south of the Arctic Circle, for the Norne oil production vessel in the Norwegian Sea. Two pilots and 10 passengers were on-board (AAIB/N 2001: 4). The operator had acquired this aircraft when it absorbed a Norwegian competitor (AAIB/N 2001: 11). It was equipped with IHUMS (AAIB/N 2001: 14). At 06:50 the crew observed a short illumination from the overspeed (or ‘OVSP’) light (AAIB/N 2001: 7). This light is primarily intended to indicate activation of an engine overspeed protection system (AAIB/N 2001: 13 and Padfield R.R. ‘Finger Trouble in the Super Puma’, Helicopter World, January-March 1990 pp 28-32) but both engines continued operating and they were not able to identify a problem (AAIB/N 2001: 7). The indication was however caused by an abnormal vibration causing a momentary loss of contact between the power turbine and its speed sensing probes (AAIB/N 2001: 98). The vibration was due to a failure developing at the gearbox end of the drive system connecting the right hand engine to the main gearbox (MGB). It is believed that two components at the MGB end of right hand high speed input shaft (known as the ‘Bendix shaft’), the splined sleeve and subsequently the splined flange (below), had become cracked to a considerable extent during previous flights. The thin walled Bendix shaft transmits (see below) power from the Makila engine (up to 1742 shp at 22850 rpm) and has flexible bellows (or diaphragms) at each end to allow relative movement between the engine and the MGB (AAIB/N 2001: 11-12). These bellows are also weak points, designed to fail first. In such an event the longer piece of the shaft is prevented from flailing by a small stub shaft (one protruding beyond the bellows at each end). About six minutes after the overspeed light first flickered the splined sleeve and flange deteriorated so as to release a lock washer and circlip (see AAIB/N 2001: Figure 6 above) into the Bendix shaft. The Bendix shaft severed (see below) under the one tonne static load imposed by the lock washer (AAIB/N 2001: 97-99). The break was between the bellows, meaning that the severed shaft flailed, generating strong vibrations. If the Bendix shaft fails the most serious hazard is that the power turbine (see below), no longer constrained by the load of the rotor system, could be accelerated by the gas generator exhaust until its turbine discs burst, releasing high-energy debris. The defence against this is an overspeed protection system designed to shut down the gas generator as the power turbine accelerates above 120% power turbine speed (Nf) (AAIB/N 2001: 13). There were no requirements for the further defence of debris containment when the AS332L was certified (AAIB/N 2001: 24). Unfortunately the progressive failure in the drive system also damaged the Nf sensors used by both the overspeed protection and Engine Electronic Control Unit (EECU). Due to a flaw in the design, not only did the loss of Nf signal cause the...
read moreMind the Handrail! – Walk-to-Work Helideck Hazard
Mind the Handrail! – Walk-to-Work Helideck Hazard A recent offshore helicopter incident has highlighted a new hazard as offshore industry practices change. A medium helicopter carried a team to a Normally Unattended Installation (NUI). After an uneventful landing, the disembarking team noticed that the folding handrail for the access steps behind the helicopter was in the up position. It was just 300mm from the tail rotor. A pitch angle of nine degrees during the landing would have been sufficient for a tail rotor strike. When a NUI is temporarily manned the Helicopter Landing Officer (HLO) must ensure these hand rails are folded down when an aircraft in on approach. When de-manning the NUI, the HLO will fold the handrail in use down as the passenger embark. So what went wrong when the last helicopter departed? Nothing! On investigation the last visit to the installation had been by a walk-to-work (or W2W) vessel, where workers transfer by stabilised gantry (VIDEO). The investigation found there was no helideck inspection as part of the W2W NUI de-manning checks. To prevent a reoccurrence Installation, Maintenance and Safety Managers need to ensure that NUI down-manning procedures include verification that the helideck is being left in a safe condition. The helicopter crew did not see the relatively small erect handrail. The UK Civil Aviation Authority (CAA) Standards for Offshore Helicopter Landing Areas (CAP437) says: Where handrails associated with helideck access/escape points exceed the height limitations given at paragraph 3.23 [shown graphically in an illustration below] they should be retractable, collapsible or removable. When retracted, collapsed or removed the rails should not impede access/egress or lead to gaps which could result in a potential fall from height. Handrails which are retractable, collapsible and removable should be painted in a contrasting colour scheme. Procedures should be in place to retract, collapse or remove them prior to helicopter arrival. Once the helicopter has landed, and the crew have indicated that passenger movement may commence…, the handrails may be raised and locked in position. The handrails should be retracted, collapsed or removed again prior to the helicopter taking off. The handrail in question appears to have been marked with faded yellow and blacks stripes, which may have been difficult to see against their background with adjacent black and dark coloured structure. There are high contrast GRP handrail options available: CAP437 chapter 3 paragraph 3.23 defines the clearance, based on the D value, required on a helideck as shown below: Note: More detailed information on this incident was shared in a safety alert by an industry association Aerossurance is a member of. Other Helideck Safety Resources Helideck Safety Alerts: Refuelling Hoses and Obstructions NTSB Recommendations on Offshore Gas Venting Passive Fire-Retarding Helideck Designs US BSEE Helideck A-NPR / Bell 430 Tail Strike Troublesome Tiedowns Helideck and Helicopter Egress Training Facilities Wrong Deck Landings FOD and an AS350B3 Accident Landing on a Yacht in Bergen UPDATE 16 April 2022: Helideck Heave Ho! Aerossurance regularly assists oil and gas companies and vessel operators review and update their helideck procedures and adverse weather policies, examine helideck structural integrity issues and provide independent assurance of helideck readiness. Aerossurance is pleased to be supporting the annual Chartered Institute of Ergonomics & Human Factors’ (CIEHF) Human Factors in Aviation Safety Conference for the third year running. We will be presenting for the second year running too. This year the conference takes...
read moreNight Offshore Training AS365N3 Accident in India 2015
Night Offshore Training AS365N3 Accident in India (VT-PWF, 2015) The Indian Aircraft Accident Investigation Bureau (IAAIB) has issued their report into the fatal loss of Airbus Helicopters AS365N3 VT-PWF, operated by Pawan Hans, while conducting night training in the ONGC Bombay High oil field on 4 November 2015. The Accident Flight: 319 seconds to Disaster The helicopter took off with just the two crew aboard from the WIS Offshore Installation at 19:10 local time, heading for the Ron Tappmeyer drilling rig, alongside the EE Offshore Installation, 82 nm East of Mumbai. The pilot flying needed to regain his night currency to be on night medevac stand-by, having last flown offshore at night 11 months earlier on 30 November 2014. The IAAIB states: The pilot on controls was flying during dark phase of moon at night after break of nearly a year. 56 secs after takeoff…the autopilot was engaged in ALT and HDG modes. In these modes, the pilot adjust{s] power by the movement of collective stick. The helicopter was in cruise for about 3 minutes. The cruise altitude was between 550ft and 650ft AMSL with Auto-Pilot engaged. About 98 secs prior to the crash, the autopilot (upper modes ALT and HDG) was disengaged. The helicopter made a tail wind approach with speed of approximately 79 kts for Ron Tappmeyer which is to the south extremity of the South field with no other rigs nearby to provide ambient lighting which caused an abrupt loss of visual reference. …the pilot slightly moved the cyclic stick backward and the collective stick downward. Consequently, the pitch increased and the power decreased. This maneuver looks like a standard approach procedure to decrease the speed. Thereafter, the pilot moved the cyclic stick slightly to the left and began a left turn. The left turn was 50 seconds long with slight variations in roll attitude. The lateral acceleration remains between -0.03 and +0.09. The corrections did not lead to a roll attitude less than 12° to left. After the Autopilot disconnection, the pilot was “hands on” and the attitude of the helicopter was consistent with the inputs on the flight commands. No specific pilot inputs were recorded, except actions on the collective pitch in the last second of the recording. The pilot flying has probably entered conditions ideal for black hole phenomenon because of loss of horizon wherein he was not aware about the direction he was proceeding to i.e. up or down / turning right or left. [Note we have discussed this phenomena before: HEMS Black Hole Accident: “Organisational, Regulatory and Oversight Deficiencies” and Deadly Combination of Misloading and a Somatogravic Illusion: Alaskan Otter] The instructor cautioned, (though delayed), the pilot flying twice. No audio warnings were recorded…except the “Decision Height” warning which triggered 4 seconds before the end of the recording and is consistent with the height of the helicopter at that moment (200 ft). Both crew died after the helicopter impacted the sea at 116 knots. The flight lasted just 5 minutes 19 seconds. the Emergency Flotation System was not armed. Operational Issues The IAAIB observed: There is no SOP [Standard Operating Procedure] for carrying out night offshore training. There are some references in the SOP issued for Night Ambulance Operation [medevacs]. Medevac is defined in the contract signed between ONGC and PHL, and PHL is providing the helicopter for medevac purposes but, it is not one...
read moreTiger A320 Fan Cowl Door Loss & Human Factors: Singapore TSIB Report
Tiger A320 Fan Cowl Door Loss & Human Factors: Singapore TSIB Report On 16 October 2015 Tigerair Airbus A320-200 9V-TRH lost both fan cowls of its left hand IAE V2500 engine during a night take off from Singapore, bound for Chennai in India. This is one of a long series of such incidents, numbering close to 40. This occurred just two months after the UK Air Accidents Investigation Branch (AAIB) published their report into a British Airways A319 G-EUOE that lost both engine fan cowlings and suffered an associated fire on take-off from London Heathrow in 2013. The Incident Flight and the Damage The Singapore Transport Safety Investigation Bureau (TSIB) report explains: After being informed by the cabin crew of the loss of the left engine fan cowls, the flight crew levelled the aircraft off at 8,000ft. They checked and noted that all engine parameters were normal. They then decided to return to Changi Airport. When landing gears were selected down during the approach to land, a Master Warning came on, indicating that the left main landing gear was not downlocked. The approach was discontinued and the flight crew performed the manual gravity extension procedure but the Master Warning still indicated that the left main landing gear was not downlocked. The flight crew declared Mayday and flew a holding pattern to burn fuel and reduce the aircraft landing weight. Later, the flight crew performed a low fly-past, and engineers on the ground reported that the left main landing gear appeared to be down. Subsequently the aircraft landed without incident. Debris of the outboard fan cowl was found on the runway and reconstructed. The inboard fan cowl was recovered from the sea more or less in once piece by a passing ship. All the four latches (comprising four hooks at the bottom edge of the inboard fan cowl and four corresponding keepers at the bottom edge of the outboard fan cowl) were recovered. Apart from operational wear, no damage were observed on the four latches. …each of the four fan cowl latches comprises a handle with hook end at the bottom edge of the inboard fan cowl and a keeper end at the bottom edge of the outboard fan cowl. Some fan cowl debris had lodged into the left main landing gear door, and damaged the proximity sensor on the left main landing gear The aerodrome operator supplements its runway inspections with a FOD detection system. It uses multiple panning cameras along the runway to identify possible FOD. This system did spot fan cowl debris but it was interepreted as being a runway light. Only the sixth alert gave an adequate image for the duty operator to determined that there was indeed FOD on the runway. Events Prior to the Flight and Procedures The TSIB say that the evening before the aircraft had been due Base Layover (BLO) maintenance, which included checking the oil level of the integrated drive generator (IDG) of the left and right engines. According to the BLO technician, he checked the right engine IDG first. He lifted the outboard fan cowl on the IDG side to visually sight the oil level before closing it. He proceeded to check the left engine. He closed the fan cowls of the left engine and fastened the latches of the fan cowls after checking the IDGs. He said he was not interrupted while closing the fan cowls. If the fan cowl...
read more1980 MD-81 Flight Test Accident Video
1980 MD-81 Flight Test Accident Video A classic and spectacular flight test landing accident, involving McDonnell Douglas DC-9-81 (MD-81) N980DC on 2 May 1980, is shown in this 10s video: The aircraft was on a certification test flight with a mixed MD / FAA flight crew. The aim was to determine the distance to land and bring the aircraft to a full stop (as per 14 CFR 25.125). In their investigation report US National Transportation Safety Board (NTSB) explains the aircraft touched down about 2,298 feet beyond the threshold on the 15,000ft runway 22 at Edwards AFB at 125 KIAS with a vertical velocity of 16.5 ft/s (990 ft/m). The descent rate at touchdown exceeded the aircraft’s structural capability and the empennage, aft of station 1429, separated from the aircraft and the fuselage buckled in several places. The aircraft came to rest about 5,634 feet beyond the threshold. An FAA Flight Test Engineer who was standing behind the observer’s seat in the cockpit to record data broke an ankle. NTSB Analysis Amongst their analysis the NTSB comment: NTSB Probable Cause The NTSB’s probable cause was the rather unhelpful statement: The pilot’s failure to stabilize the approach as prescribed by the manufacturer’s flight test procedures. More helpfully they go on: Contributing to the cause of the accident was the lack of a requirement in the flight test procedures for other flight crewmembers to monitor and call out the critical flight parameters. Also contributing to this accident were the flight test procedures prescribed by the manufacturer for demonstrating the aircraft’s landing performance which involved vertical descent rates approaching the design load limits of the aircraft. NTSB Safety Recommendations Two safety recommendations were raised: Safety Recommendation A-82-024 THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: REVISE THE PROCEDURES WHICH ARE CURRENTLY BEING USED TO DEMONSTRATE MINIMUM LANDING DISTANCES FOR COMPLIANCE WITH 14 CFR 25.125 FOR CERTIFICATION OF TRANSPORT CATEGORY AIRPLANES TO: (A) PROVIDE A HIGHER MARGIN OF SAFETY DURING CERTIFICATION AND (B) ESTABLISH LANDING DISTANCES WHICH ARE MORE REPRESENTATIVE OF THOSE ENCOUNTERED WHEN AN AIRPLANE IS OPERATED DURING AIR CARRIER SERVICE. The FAA proposed closure based on a revision to the Engineering Flight Test Guide for Transport Category Airplanes. The NTSB responded that: The revised procedures, however, do not satisfy the intent of part (b) of Safety Recommendation A-82-24 which addresses the unrealistic nature of landing distance data which results from the disparity between certification procedures and safe operational practices. They classified this action as: Closed – Unacceptable Action Safety Recommendation A-82-025 THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: UPON ADOPTION OF REVISED PROCEDURES FOR DEMONSTRATING OPERATIONAL LANDING DISTANCES FOR COMPLIANCE WITH 14 CFR 25.125, REVIEW THE OPERATIONAL RUNWAY LENGTH LIMITATIONS IN 14 CFR 121.195 WHICH ARE APPLIED TO CERTIFICATION LANDING DISTANCES SO THAT THEY DO NOT UNJUSTIFIABLY PENALIZE THE OPERATIONAL SPECIFICATIONS OF AIRPLANES. The FAA response and the NTSB assessment were similar to the previous recommendation: Closed – Unacceptable Action Another MD-80 Flight Test Accident Just over 6 weeks later, on 19 June 1980 N1002G, the second DC-9-80 series prototype was making a certification test flight with an FAA test pilot in command to demonstrate that the aircraft could be landed safely with a complete hydraulic system failure. As the NTSB describe: The aircraft touched down at around 175 knots just past the arresting cable, 1,831 feet beyond the landing threshold of the runway. Reverse was used before touchdown of the...
read moreThe Jet that Almost ‘Landed’ on a Tower Block
The Jet that Almost ‘Landed’ on a Tower Block On 16 August 2007 an airliner on a night approach at Dublin lined-up not on the runway but on the lights of a tower block. We look at the investigation, the lessons and the prompt safety action taken. The Incident Flight The McDonnell Douglas DC-9-83 (MD-83) G-FLTM, of now defunct British airline Flightline, had departed Lisbon for Dublin with 118 people on-board and the Co-pilot as Pilot Flying (PF). According to the investigation report of the Irish Air Accident Investigation Unit (AAIU): The flight progressed without incident until commencing its approach to Dublin Airport. The NOTAM for Dublin clearly indicated that the main RWY 10-28 would be closed later that evening for maintenance. Despite having the NOTAM.. the Flight Crew…briefed for, a standard descent and ILS approach on RWY 28. RWY 34 was in fact in use and during decent the Automated Terminal Information Service (ATIS) message alerted the crew. The track distance for descent was now considerably shorter [than the crew expected] and the Flight Crew had to brief and prepare for a non-precision approach on RWY 34. The approach was made at night; the weather and visibility were good. During the approach, at approximately 5 nautical miles (nm) from touchdown, the aircraft began to deviate left of the approach course. The Flight Crew misidentified other lighting in urban Dublin as that of RWY 34 (we discuss that lighting below). The PF, contrary to the Company SOP, looked out early for visual reference, and saw almost straight ahead what appeared to be the approach lightning of RWY 34. However: With the wind from 260º at 12 kts, the aircraft would have been on a heading of 336° to make good a track along the inbound course of 342°. The aircraft was thus pointing to the left and towards the ‘false’ lighting. The Auto Pilot remained engaged and the heading was adjusted to the left by the PF. The aircraft was then turned further left, steering the aircraft away from the required inbound course. Descent was continued with crossing altitudes checked by the PNF. The PNF, checking the crossing altitudes, stated that the aircraft was ‘too high’ but the PF was looking at what he considers to be the PAPI, which indicated an apparent ‘all red’ or ‘too low’ indication. At that moment there was considerable confusion on the flight deck. Meanwhile the Air Movements Controller (AMC) was the sole occupant of the Tower as the Surface Movements Controller (SMC) had left almost 20 minutes earlier at 23:15 as the traffic level was so low. The AMC was however distracted by radio calls from construction vehicles working on the closed runway. The aircraft continued to descend below the Minimum Descent Altitude (MDA) without proper visual identification of the runway…. [The PF] was puzzled by the absence of runway edge lights beyond what appeared to be the touchdown point. He queried ATC as to the status of the runway lights and immediately the Tower controller issued instructions to turn right and climb. The aircraft had descended to 580 ft above mean sea level (AMSL) before executing a go-around. When [subsequently] asked why he [the PF] did not execute a go-around [himself], he said he considered it to be a decision for the Commander. He only executed a...
read moreDeadly Combination of Misloading and a Somatogravic Illusion: Alaskan Otter
Deadly Combination of Misloading and a Somatogravic Illusion: Alaskan Otter A turbine powered de Havilland DHC-3 Otter floatplane, N928RK, operated by Rainbow King Lodge, suffered a Loss of Control – Inflight (LOCI-I) shortly after take off on 15 September 2015 near Iliamna, Alaska. Three of the 10 persons on board were killed and 5 received serious injuries. In their investigation report US National Transportation Safety Board (NTSB) explain that the aircraft… …was being used to transport sport-fishing clients and guides to a remote area for a day of salmon fishing. The pilot said that because the passengers “were familiar” with flying in the aircraft he did not conduct the mandatory briefing before they departed at 0605 Local Time. According to the US Naval Observatory Astronomical Applications Department, civil twilight began at 0706, and sunrise was at 0748. [A] lodge employee reported it was dark but that he was still able to watch the airplane as it started its westerly takeoff run. The pilot stated that, during takeoff, he looks outside the airplane and does not focus on his instruments. He said the lack of light caused him to lost visual cues after the airplane became airborne. The witness said that… ….after liftoff, the airplane began to climb and then descended, and the floats subsequently struck the water’s surface. The airplane then became airborne again and veered right, but he lost sight of it behind an area of rising terrain. According to the automatic dependent surveillance-broadcast [ADS-B] data, the airplane then began a gradual right turn before reaching a maximum altitude of 175 ft above the water. The accident again demonstrates the great value of good ADS-B coverage and recording in accident investigation. The airplane then descended toward the water’s surface, flew low over the water and terrain, and then climbed briefly again before it impacted terrain. Rainbow King Lodge had no procedures in place or equipment available for calculating preflight weight and balance. [The Pilot] stated that the Otter typically flew with a load of about six people [and]…he did not weigh the cargo nor did he document any weight and balance calculations. When asked how he calculated the airplane’s weight and balance before departure, the pilot said he “guesstimated” it. A postaccident weight and balance study using the passenger weights, weighed cargo, and fuel load showed that the airplane exceeded its maximum gross weight of 8,367 lbs by about 508.6 lbs and that the center of gravity (CG) was 4.08 inches aft of the aft CG limit. Data from the airplane’s automatic dependent surveillance-broadcast (ADS-B) showed that the airplane was at or below the stall speeds listed in the airplane flight manual during both the initial and second climbs. The ADS-B data show that, because the pilot failed to determine the airplane’s actual preflight weight and CG and loaded and operated outside of the weight and CG limits, the airplane did not attain a proper airspeed to climb, and it experienced an aerodynamic stall. The pilot commented that: …the owners did not put any pressure on him regarding flights [and] that he was never pressured to fly in weather or fly heavy. It is a competitive industry, and all of the lodges fly to challenging locations. He felt that waiting until there was better ambient light might have helped. The NTSB add: There were insufficient external cues available to the pilot to reliably...
read moreA320 Rolls Back on Stand: Incomplete Maintenance Procedures and Ground Handling Deviations
A320 Rolls Back on Stand: Incomplete Maintenance Procedures and Ground Handling Deviations The UK Air Accidents Investigation Branch (AAIB) has reported on a case where parked EasyJet Airbus A32o-214 G-EZTM rolled back and struck ground equipment on Stand 559 at London Gatwick airport on 26 March 2017. The flight crew had boarded the aircraft prior and completed cockpit preparation (including confirming the parking brake was ON). However, a brake system defect, which had occurred on the previous sector, was also being investigated while the aircraft was parked. As part of this process, Aircraft Maintenance Manual (AMM) Task 32-42-00-710-001-A Rev.55 was being actioned. This required the parking brake to be selected OFF. On completion of the task it remained in the OFF position, as there was no requirement in the task to select the parking brake ON again. This is a classic poor procedure that fails to return the aircraft to a safe state on completion. The flight crew were unaware the brake was now OFF. The AAIB make no comment on the liaison between maintenance personnel and flight crew. Prior to departure, with the forward steps still in position, the ground handling staff arrived and connected a tug, before removing the chocks as part of their pre-departure checks. However, the operator’s procedures required chocks to remain in place until all ground equipment is clear of the aircraft. The tug driver then realised the tug radio was not working and disconnected the tug to replace it with a fully serviceable one. There was no communication with the flight crew at this point. Unconnected from the tug, unchocked and with the brakes OFF, the aircraft was now free to roll backwards, which it did. The flight crew noticed the movement and applied the footbrakes but not before the aircraft struck the steps, damaging the fuselage and Door 1L. There were no injuries to the 168 persons on board or ground staff. Safety Actions The operator’s engineering department is reviewing the AMM task (32-42-00-710-001-A Rev.55) and will make recommendations to the aircraft manufacturer to amend the AMM accordingly. The ground handling company: Raised awareness of the event; Retrained the staff involved concerning the correct chocking procedures; The defective equipment local operating procedure has been reissued to all staff to prevent inoperative equipment being available for use. Our Comment A classic example of ‘all the holes’ lining up at once, noticeably at the interfaces between multiple teams. See also: Ground Collision Under Pressure: Challenger vs ATV: 1-0 Pressure, changes of plan and distractions all feature in this ground collision where a Challenger overturned an All Terrain Vehicle. UPDATE 14 January 2018: A320 Collided with Two De-Icing Trucks: Misinterpretation of communication due to a lack of standardised phraseology was a factor this incident say the BFU, when an A320 attempted to to return to stand after a checklist error. UPDATE 25 January 2018: Jetstar Dispatcher Forced to Run After Distracted Pushback A dispatcher was forced to run when an aircraft started to taxi while he was still connected to it after the crew became distracted, skipped procedural steps and misidentified the dispatcher. UPDATE 22 April 2018: A330 Starts to Taxi Before Tug is Clear ATSB say misunderstandings by the parties involved led to incorrect expectations and the aircraft beginning to taxi prior to the tug moving clear. UPDATE 8 April 2020: NTSB Confirms United Airlines Maintenance Error After 12 Years UPDATE 12 October 2020: Runaway Dash 8 Q400 at Aberdeen after Miscommunication Over Chocks...
read moreA320 Flown on After Damaging Heavy Landing
A320 Flown on After Damaging Heavy Landing (Germania D-ASTP) The Spanish air accident investigators, the CIAIAC (Investigación de accidentes e incidentes de aviación civil), released a preliminary report (in Spanish) on 28 June 2017 on an incident involving Germania Airbus A321-200 D-ASTP on 16 July 2016. The aircraft was performing a flight from Düsseldorf to Fuerteventura, in the Canary Islands. The crew commenced a go-around due to the approach becoming unstabilised but still touched down hard with vertical acceleration subsequently determined to have been 3.32 g. After the subsequent landing: The crew performed an external check on the aircraft without encountering anomalies. The Commander established contact with the [operator’s] maintenance control centre (MOC) in Germany, to request confirmation and support on the on interpretation of the automatic report issued by the aircraft with respect to the hard landing. Its not clear what response (if any) was received as the CIAIAC go on: Due to the absence of maintenance support at the Fuerteventura airport and, in the absence of a criterion on the meaning of landing report code ‘Hard’, the crew decided to make the return flight to Dusseldorf. The aircraft departed with the return passengers aboard 83 minutes after landing. Once in Düsseldorf the aircraft was removed from service for inspection. The left hand Main Landing Gear (MLG) was found damaged and the right hand MLG also needed replacement. The CIAIAC note the first report of an occurrence was only received by them on 30 August 2016, over 2 months after the incident. Data that confirmed the touch down had been at 3.32g was only received in mid November 2016. The CIAIAC say their investigative research is complete and the final report is due ‘shortly’. UPDATE 22 December 2017: The CIAIAC issue their final report: The copilot, along with the captain, who had an instructor rating, decided to make the approach with thrust and control in manual. This resulted in a go-around after making contact with the runway. Until that moment, the flight had been uneventful. During the final approach phase, the approach unstabilized, primarily due to a drop in speed and to the airplane falling too low, and the captain executed a go-around. CIAIAC says the carrier acknowledged that its Airbus crews were “not well trained” for manual approaches owing to a “routine practice” of using automatic systems. The aircraft automatically generated and sent, via ACARS, an A15 hard-landing report to the company’s control center and to the manufacturer. The A15 or LOAD<15> report is generated if The normal acceleration is greater than 2.6 g at touchdown. If the aircraft weight exceeds the maximum landing gross weight, the normal acceleration is reduced to 1.7 g. The rate of descent on the radio altimeter is greater than 9 ft/sec at touchdown. If the aircraft weight exceeds the maximum landing gross weight, the radio altimeter descent rate is reduced to 6 ft/sec. During a bounced landing, the normal acceleration exceeds 2.6 g. The normal acceleration data is provided by an accelerometer mounted near the aircraft’s centre of gravity, though the sample rate means its possible the peak value may be missed. The investigators go on to say: Due to its physical effects, the crew realized that they had had a hard landing, and the captain apologized to the passengers and explained to them what had happened as they waited to be disembarked. But the crew did not have...
read moreCommon Comet Misconceptions and Collaborative Contribution to Safety
Common Comet Misconceptions and Collaborative Contribution to Safety Recently the 68th anniversary of the first flight of the prototype G-ALVG of pioneering jet airliner the de Havilland DH-106 Comet occured. As noted by Richard Gale of ADS: On Saturday 27th July 1949, the de Havilland Comet took off from Hatfield Aerodrome for its inaugural flight; reaching 10,000ft and circling the skies for approximately 31 mins. In the three years it took from the original drawing board to the first flight, the Comet instantly doubled the speed and altitude of air transport. It also brought in a whole range of new and innovative technology such as integral wing fuel tanks, engine-bled air for pressurisation and de-icing, and airbrakes. After a production line was set up, the first pure jet powered commercial flight took place in May 1952 to Johannesburg. In-Flight Break-Ups Tragically the Comet is also remembered for a series of in-flight break-ups in its first 2 years in service: 2 May 1953 British Overseas Airways Corporation (BOAC) Flight 783, Comet 1 G-ALYV, near Calcutta, India (43 fatalities) 10 January 1954 BOAC Flight 781, Comet 1 G-ALYP, Mediterranean, near Elba, Italy (35 fatalities) 8 April 1954 South African Airways (SAA) Flight 201, Comet 1 G-ALYY, near Naples, Italy (21 fatalities) The G-ALYV Calcutta accident occurred in a severe thunderstorms and the Court of Inquiry concluded the cause was: Structural failure of the airframe during flight through a thunder squall. In the opinion of the Court, the structural failure was due to overstressing which resulted from either: (1) Severe gusts encountered in the thunder squall, or (2) Overcontrolling or loss of control by the pilot when flying through the thunderstorm. As the FAA Lessons Learnt database notes, the cause this accident was reconsidered after subsequent accidents, and: The official cause of the Calcutta crash has never been anything other than the storm. The G-ALYP Elba accident occurred about 20 minutes into the flight as the aircraft climbed through 27,000 feet… …transmission from the crew ceased mid-sentence, indicating a failure of the aircraft with “catastrophic suddenness.” Witnesses on the island of Elba, Italy, saw the aircraft fall into the sea in flames. The search and salvage off Elba included the use of novel technologies, such as an underwater TV camera and continued during the summer of 1954: As described in the FAA Lessons Learnt database: The Comet fleet was grounded while investigation began and while de Havilland made modifications “to cover every possibility that imagination has suggested as a likely cause of the disaster.” These modifications were made to address any possible cause of failure including flutter of control surfaces, primary structural failure due to gusts, flying controls, explosive decompression, engine fire, failure of a turbine blade, and fatigue of the wing. Fatigue of the fuselage was not considered as a cause at this time, nor was a modification made to compensate for it. As these modifications were made, and while wreckage was still being recovered, the British Minister of Transport and Civil Aviation noted “the nature and extent of the modifications planned… and whilst the Calcutta disaster is completely accounted for… we cannot eliminate that the accident might have been due to some other cause which was possibly common to both disasters.” Believing the unknown cause of possibly two accidents had been fixed during the massive modification project, Comet flight was...
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