CHINA AIRLINES (CAL) says the US National Transportation Safety Board (NTSB) and Boeing have eliminated pilot error as a cause of the Boeing MD-11 accident at Hong Kong's Chek Lap Kok Airport last August.
The MD-11, operating a flight from Bangkok to Hong Kong, with 315 people on board, crashed during a tropical storm while landing on 22 August, killing three passengers and seriously injuring 15.
The MD-11 rolled inverted after the right wing broke away and the tri-jet came to rest by the side of the runway upside down and on fire.
According to CAL president Sandy Liu, the NTSB investigators have cleared the pilots of all error "and the investigation is focusing on the weather and on the airport". He says Boeing, the NTSB and CAL ran the accident sequence in a simulator many times before absolving the pilot of error.
CAL vice-president of operations Alfred Kupfershmied says a strong downdraft was responsible for the accident. "In the final few seconds, the last 500ft [150m], the pilot could do nothing," he says. "The aircraft was pushed down on to the runway - it was very unlucky".
Kupfershmied says Chek Lap Kok is notorious among pilots for difficult flying conditions.
The airport is adjacent to 1,000m mountain peaks on nearby Lantau Island. Formerly of Lufthansa Technik, Kupfershmied was appointed by CAL last month. He accumulated most of his 12,000 flying hours with Swissair on McDonnell Douglas DC-10s and MD-11s.
The August accident was CAL's fourth hull loss in the past seven years. Kupfershmied is tasked with improving CAL's poor safety record.

La relazione è lo "statement" richiesto al comandante dall'autorità investigativa di Hong Kong e per opportuna cautela e rispetto del collega [del quale non intendiamo riferire dati personali ad eccezione delle ore totali di volo] lo abbiamo riscritto in terza persona omettendo particolari non rilevanti ai fini della comprensione dell'evento.
In occasione di questo incidente non potemmo fare a meno di ricordare l'altro incidente ad un MD11 distrutto da un incendio a Newark [FedEx Cargo, 31 luglio 1997] dopo che aveva perso un'ala in atterraggio, in quanto i due eventi apparivano molto simili nella dinamica e nel risultato. Le foto [alla fine dell'articolo] sono molto eloquenti a riguardo.
Per consentire un confronto immediato tra i due eventi proponiamo, a seguire, l'abstract dell' accident report del NTSB. Quindi riportiamo il capitolo, tratto dal rapporto completo del disastro di Newark, in cui viene fatta menzione dell'incidente di Hong Kong in quanto alla sua investigazione partecipò lo stesso team del NTSB. Nello stesso rapporto, molto voluminoso e dettagliato, che può essere considerato materiale di studio per coloro che debbono capire che cosa è un'investigazione, sono citati altri incidenti con dinamiche di cedimento strutturale similari.
Pertanto, nell'invitare alla lettura tutti coloro realmente motivati all'approfondimento e capaci di cogliere gli aspetti politico-economico-industriali di un'investigazione di questo genere, indichiamo il collegamento per il download del file.pdf con l'intero Accident Report.

1. What follows is based on the Captain's report of crash at Hong Kong International Airport (Chek Lap Kok) of the Boeing MD-11 Aircraft, CAL 642, on August 22^nd 1999.
2. The Captain [italian] had extensive flying experience as follows:
   Total flight hours 17,900
   Type Experience: 3,260 hours flying MD-11s for 8 years
   Employer: China Airlines since 1997, previous employer(s) 33 years with Alitalia as Co-Pilot/First Officer/Captain/Instructor/Check Pilot
   The First Officer [taiwanese], was fully licensed and proficient.
3. The Captain had never previously been involved in any accidents and he was particularly distressed to have been involved in a loss of life accident. He was therefore very concerned to ensure that the full and accurate facts of the matter were known to all relevant parties.
4. The flight in question was routed from Bangkok, Thailand to Taipei,Taiwan via Hong Kong.
   Flight crew knew from Met briefing in Bangkok that typhoon "Sam" was close to Hong Kong International Airport and they accordingly requested, and received, more fuel after changing the alternate airport from Kaoshung to Taipei in case diversion from Hong Kong was needed. With more fuel over Hong Kong, in case of a diversion they could go straight to the final destination of Taipei.
   However, the typhoon was not mentioned in the Automated Terminal Information Service ("ATIS") weather transmission the pilots listened before commencing descent, nor was there any indication of wet runway. They received 3 different ATIS transmissions; Victor, Whisky and X-Ray. On ATIS transmissions coded Victor and Whisky, there was possibly a warning of gusting at 28 to 36 knots. They mentioned turbulence and maybe wind shear during the approach. When nearing Hong Kong International Airport (before commencing the descent) the ATIS transmission merely broadcast the wind, temperature, cloud cover, precipitation and turbulence. The Captain recalled they were given actuals, on ATIS message coded 'X-Ray', of a mean surface wind 300/25 or maybe 29, broken cloud, possibly precipitation (the Captain could not remember if there was any, but sure it was not heavy), possibly wind shear and moderate turbulence on the approach. The Captain subsequently asked the Control Tower for a wind check when they were at approximately 1,000 feet a.g.l. [above ground level] on the I.L.S. and they were given 300/34 but with no mention of gusting or wind shear, neither was there any mention of the runway being wet. The visibility was given as 1,600 metres.
5. The flight to Hong Kong International Airport had been uneventful. No emergency calls were made at any stage.
6. The Captain stated that he was under no particular fuel, commercial, or other, pressure out of the ordinary to land at Hong Kong International Airport and it was his own ultimately decision to land; the First Officer was in agreement with this decision until the very last moment - although of a sudden change of his mind on touch down.
7. The Captain and the First Officer, began to make preparations to land at Hong Kong International Airport and they both listened to all the radio information received.
8. On the approach, they were coming from the south. They had been told that the active runway was 25R, but just before intercepting the localizer they were given a runway change to 25L. No reason was given for this change. Aircraft crossed both localizers at about 90° and it was then vectored left 120° by radar back towards the localizer; closing the localizer at approximately 30°.They crossed the 25R localizer and established inbound on the 25L localizer at 4,000 feet.
9. They intercepted the glideslope indicator and commenced descent. The aircraft was within landing weight limits. The flaps were then set and the landing gear was extended; pilots followed the final approach checklist. Captain's windscreen wipers were set on high speed and he established visual contact with the runway at approximately 800 feet and uncoupled the autopilot to fly a manual approach - visibility was moderate.
10. The last wind flight crew had been given was 300/34. That was a wind speed of 34 knots (39 m.p.h.) from 300° Magnetic. The runway centre line was 253° Magnetic with local variation 2° west. The Captain calculated the cross wind component for a wet runway by taking the wind as being 45° off the nose, and multiplying 34 knots by the cosine of 45° which gave him the cross wind of 24 knots (the calculation was cos 45° = 0.7; 30 x 0.7 = 21; 4 x 0.7 = 3; 21+3=24) The Company's cross wind limit for the MD-11 aircraft was 24 knots for a wet runway, and 35 knots for a dry or damp runway, and flight crew aimed to the wet limit for conservative purposes. The First Officer performed the same calculation independently. Both the Captain and the First Officer agreed that they were alright for landing in that wind. - Captain said "it is O.K. to land" and the First Officer agreed. The manual for the MD-11 gives the cross wind limit as 35 knots. The Captain knew that it would be marginal regarding a wet runway, but he was only witnessing light rain or none: at touch-down there was haze on the runway. The Captain knew that runway surface was grooved and perfectly drained, in this sense he was conservative.
11. At the 500 foot point, both pilots have to agree to continue with the landing. This was done.
12. The wind indication on instrument panel [INS wind] was between 210° and 310° and 29 knots at 300 feet. They had experienced a 10 knot drop [170 knots (target approach speed) to 160 knots] in indicated air speed (IAS) at about 150-200 feet, which Captain corrected by the application of power. On the final approach the manual flying was not particularly demanding, it was not easy but quite manageable. At all times the aircraft was on the extended centre line, but it might have gone below the glide slope a bit. When over the runway, at about 50 feet, the Captain commenced a flare, which involves reducing the rate of descent by increasing the pitch angle and reducing power, but nothing happened; so he increased the pitch further, still with no apparent effect. At this stage there was another marked drop in airspeed, this time from 170 knots to 152 knots. Landing reference speed was 152 knots.
13. At the touch down point the First Officer called for the landing to be aborted by shouting 'go around'. In Captain's judgment that was far too late, and it would have been far more dangerous to overshoot from that position than to execute the landing, as there was no possibility of avoiding contact with the ground. If the "go around" procedure had been initiated at that stage, there would have been a further major problem to take into account, that was landing with the ground spoilers disarmed.
14. The Captain felt that any further increase in pitch, or application of take-off power ('go around thrust') would aggravate the situation and so he elected to land. Due to the strong side wind he had some bank on throughout the final approach, no more than 4°, according to the Captain, although the First Officer declared in his statement they landed with a 15° bank angle. The First Officer also stated that the wing tip touched the runway first, whilst the Captain knew that they landed in the touch down zone at the centre line with a 3° or 4° bank angle to the right. The Captain had no feeling of the engine impacting the runway. His belief was that they landed on the right main wheels and that the undercarriage broke and shattered. The wing fractured together with the landing gear, causing the aircraft to "flip" over due to the intact left wing lifting up. Regarding to what was wrong in the pre-touch down phase, the Captain would discount the cross wind, as the aircraft was fully stabilized on the runway centre line, and had been for the whole final approach. The sudden change in IAS was probably due to the presence of wind shear. Wind shear was often very localized, and there were no wind shear sensors actually at the runway threshold.
15. There was no fire or explosion at any stage before touchdown nor was there any violent shaking of the plane before touchdown. The Captain declared that he landed the MD11 in worse conditions than those evident on that circumstance. The aircraft was perfectly manageable until it was over the runway when something did not happen. The Captain flared the aircraft but there was no vertical speed reduction. The plane was caught in a dowridraft - a vertically moving air mass - according to his personal understanding, and there was no way left for the pilot to put the aircraft into a positive rate of climb.
    With hindsight the Captain said that they were very fortunate in having the throttles set at "idle power" at touch down. Had the throttles not been at idle power then, following the aircraft flipping over and with left and central engines at full thrust, the aftermath of the crash would have been even more serious than what actually occurred.

I caratteri in grassetto sono stati usati per rimarcare aspetti interessanti per il pilota professionista o per individuare circostanze che danno adito a dubbi sul comportamento della macchina oppure delle discrepanze nella visione degli eventi da parte del First Officer.
Dopo il contatto del carrello destro, peraltro non avvertito dai piloti come atterraggio pesante, il comandante ebbe la sensazione che l'aeromobile stesse galleggiando come se avesse rimbalzato al primo contatto. Tale sensazione, che avrebbe dovuto essere accompagnata dalla visione di un riallontanamento dalla pista, creò un conflitto percettivo a causa dell'avvicinamento del muso al terreno, quindi, un disorientamento, aggravato dall'inizio di una rotazione in senso antiorario dell'immagine esterna. Si tenga presente la scarsa condizione di luce alle ore 18.45 locali. Gli istanti seguenti, e precedenti l'arresto definitivo dell'aeromobile fuori pista in posizione invertita, sono forse immaginabili nelle percezioni sensoriali dei piloti non certo nello stress emozionale a cui furono sottoposti. Le manovre di primo intervento furono eseguite dai piloti letteralmente appesi alle poltrone e allo sgancio delle cinture ritrovarsi a cadere verso il soffitto deve essere stato un elemento di ulteriore disorientamento che ritroviamo nel tentativo di identificare il lato sinistro e destro dell'aeromobile per favorire l'evacuazione degli oltre trecento passeggeri.

16. As soon as the aircraft came to rest pilots shut down the engines and turned off the fuel switches. Both pilots went back to the cabin through the cockpit door. The fuselage had capsized and was leaning nose down and to the left side; it was completely obscured. The Captain heard a noise like a discharging gas bottle activating the door on the left side (although it was actually door 1 on the right hand side). The door opened and through a dim light from outside he could see that the nearby aisle was impassable and the galley's frame was obstructing their way to the opposite door (1 left), both pilot therefore exited from door 1 right and went around the aircraft's nose before reaching door 1 left from the outside.
    The Captain intention was to open that door using the external handle but he found it already opened. They entered through the door and found the aisle on that side passable so, from that position, standing on the galley's roof, they started to evacuate the passengers coming from the cabin. They helped them over the debris, over the threshold of door 1 left and helped them to the ground.
17. After some 40 or 50 persons had exited, the fire services joined the wreckage. The space in the galley and the aisle was very restricted and dark and the flight crew thought it was better at that stage to leave the job to the firemen who were appropriately equipped with all their usual emergency equipment. Both pilots left the aircraft from door 1 left.
18. They stayed near the aircraft for the next hour giving information and answering questions as necessary. They tried to help in the coordination of the evacuation of passengers. After about an hour passed no more passengers were emerging and a fireman and a CAL employee advised the Captain that there was no more risk of fire and the rescue of anybody else on board required the skilled work of the fire services. As a consequence the Captain considered their attendance at the crash site no longer essential or useful and so they boarded the last waiting bus (an empty one) in order to make their way to the air terminal.
19. The flight crew went to the Regal Airport Hotel where they had a tape recorded interview with two representatives of the Hong Kong Civil Aviation Department. This was about two hours after the accident and both pilots were obviously rather distressed at that time since they had not even changed from their flying clothes [covered in fuel] - They were simply given a couple of blankets. Later they also gave a urine sample.
20. On the next day (Monday 23^rd August) both pilots went for a medical examination. On the morning of Tuesday 24^th August the Captain was supposed to have an official interview with the Hong Kong Civil Aviation Department but by that time he had the support of the Airline Officers Association representatives. The Hong Kong CAD would not accept the presence of these representatives although most of that day was spent in the hotel exchanging fax messages to agree on the issue with the Civil Aviation Department. At about 6 p.m. the representatives from the Hong Kong Civil Aviation Department, left the hotel without having interviewed the Captain.
21. The Captain was visited again on Wednesday 25^th August, by the same doctor had examined him on the previous Monday. He found the Captain unfit for flight duties until reviewed by a specialist in Aviation medicine in his own country. That afternoon he was called by CAL's MD-11 Chief Pilot, to collect his belongings that had been found in the plane but not the passport that had not been found.
22. Back in his hotel room the Captain was pestered by newspaper photographers and he called the Airline Officers' Association people who suggested he should leave the hotel. He went to the Italian Consulate in order to organise new documentation and, given the medical advice, he left Hong Kong on a KLM flight to Amsterdam on the morning of Thursday 26^th August.
23. China Airlines issued a bulletin [1^st September 1999] in which they amended their maximum cross wind limit for wet runways to 20 knots. Also, flight crew have been warned to be very careful on landing given the circumstances of the accident, which CAL put down to wind shear. If a stable approach to Hong Kong International Airport is not possible then the pilots are instructed to "execute missed approach immediately".
24. There are a number of issues that the Captain of CAL 642 considered in his statement relevant in terms of cause of the accident.
    1) The go around call by the First Officer came when the aircraft was not recoverable.
    The Captain believe there may be difficulties with the MD11 that become particular manifest in particular landing conditions. The airplane simply does not react to certain commands and in this case it did not react to the attempt to "flare" the aircraft, which would have decreased the angle of descent.
    2) The Captain believed that wind-shear was a factor in this accident. They were cleared to land on runway 25 R but at the moment of interception they were instructed to land on 25 L by the Control Tower. Runway 25L was down wind to the terminal building whereas runway 25R has no obstacle. This might have been a factor leading to wind-shear problem. There were no wind shear sensors over the runway and this was a particular potential problem in the area of the touchdown zone of runway 25L to which they were diverted. Many Cathay Pacific pilots reported concern about wind shear problems over the runway at Hong Kong International Airport.
    3) There might have been another factor in the accident and that was a maintenance problem. It was well known by various people in CAL that the right landing gear had been taken to the U.S.A. for examination by Boeing due to previous defects.
    4) The Captain have learned subsequently that in the two hours preceding their landing there were 4 missed approaches and 5 diversions due to the weather conditions at Hong Kong. They were not informed at the time that this had occurred, nor were they given any supplementary information. Had the Captain known about the actions of other pilots, he should have been more on his guard and he should have questioned the Runway change from 25R to 25L. There was no way that he could have known anything concerning these missed approaches and diversions as Air Traffic Control did not pass this vital information to him. So far as he was aware no aircraft had experienced any problem landing at Hong Kong that night.

Il quadro risultante dalla testimonianza diretta del comandante del CAL642, per quanto riguarda la fase immediatamente precedente il contatto con la pista, rientra in una tipologia di scenario meteorologico e ATC che viene incontrata spesso nelle operazioni di volo.
Sono condizioni che restringono in modo significativo i margini disponibili per decisioni od azioni alternative o di fuga, ed in realtà riducono il margine per l'errore o l'imprevisto. Ma questa erosione di margine può, in caso di ulteriori elementi di disturbo, dare per risultato un evento catastrofico? Certamente no! Il margine in termini di cautele operative che può assumere il pilota è aleatorio, esso varia in funzione di troppi elementi diversi. E poi dipende essenzialmente da fattori umani. Ecco allora che il vero margine, quello che il pilota o altri non possono intaccare, a meno di impiego al di fuori di ogni regola, deve essere nella macchina, deve essere strutturale, deve essere nel progetto e nella manuatenzione della macchina. Certamente un aeromobile non può rispondere a specifiche da costruzioni edili ma l'attestarsi dei costruttori su requisiti minimi delle norme di certificazione può essere un grosso rischio. Specialmente quando tali requisiti sono "stirati" o "pilotati" per consentire la concorrenza nell'esercizio con altri progetti [leggi aeromobili] più conservativi, ma certamente più solidi, più "pilot friendly" oppure, come si suol dire, "good father".

Abstract: On July 31, 1997, about 0132 eastern daylight time, a McDonnell Douglas MD-11, N611FE, operated by Federal Express, Inc., (FedEx) as flight 14, crashed while landing on runway 22R at Newark International Airport, Newark, New Jersey (EWR). The regularly scheduled cargo flight originated in Singapore on July 30 with intermediate stops in Penang, Malaysia; Taipei, Taiwan; and Anchorage, Alaska. The flight from Anchorage International Airport to EWR was conducted on an instrument flight rules flight plan and operated under the provisions of 14 Code of Federal Regulations Part 121. On board were the captain and first officer, who had taken over the flight in Anchorage for the final leg to EWR, one jumpseat passenger, and two cabin passengers. All five occupants received minor injuries in the crash and during subsequent egress through a cockpit window. The airplane was destroyed by impact and a postcrash fire.
The National Transportation Safety Board determines that the probable cause of this accident was the captain’s overcontrol of the airplane during the landing and his failure to execute a go-around from a destabilized flare. Contributing to the accident was the captain’s concern with touching down early to ensure adequate stopping distance.
Safety issues discussed in this report focus on landing techniques, bounced landing recovery, and training tools and policies that promote proactive decision-making to go around if an approach is unstabilized. Safety issues also include the use of on board computers to determine the required runway length for landing, MD-11 handling characteristics and structural integrity requirements, and hard landing inspection requirements. Tracking hazardous materials continues to be a safety issue and is also discussed in the report.
Safety recommendations concerning these issues are addressed to the Federal Aviation Administration.

On August 22, 1999, a China Airlines MD-11 crashed during a landing approach to Hong Kong International Airport. Of the 315 passengers and crew aboard, two were fatally injured, one passenger died later at a hospital, and 199 received various injuries.
The aircraft was destroyed by impact and subsequent fire. The weather at the time of the accident included high winds and rain.
According to the Hong Kong Civil Aviation Department, after obtaining visual contact with the runway, the captain disconnected the autopilot but left the autothrottle system engaged. The airplane then continued to track the extended centerline but descended and stabilized slightly low on the glideslope. At around 50 feet above the runway, coincident with the reduction of power to flight idle by the autothrottle system and an increase in pitch attitude, the indicated airspeed reduced from 170 knots to 152 knots immediately before touchdown. Although an attempt was made to flare the airplane in a slightly right-wing-down attitude (less than 4°), the sink rate was maintained and a hard landing occurred. The right main wheels contacted the runway first, followed by the right engine cowling; the right landing gear and wing separated as the aircraft rolled inverted.
The right wing front spar fractured at station (STA) 268 (4 inches outboard from the STA 264 bulkhead that separates the #2 and #3 fuel tanks). This was a vertical fracture that intersected the lower and upper cap. The rear spar fractured at STA 222 at the lower cap. The rear spar fracture progressed diagonally upwards and inward to the upper cap at STA 185.
Preliminary calculations conducted by the Safety Board indicate that the airplane’s rate of descent at impact was 18 to 20 fps. This accident is still under investigation by the Hong Kong Civil Aviation Department.

Per contribuire con ulteriori elementi di giudizio ad una visione unificata degli incidenti in atterraggio dell'MD11, tra i tanti che hanno afflitto questo aeromobile, e chi ne era ai comandi, da quando entrò in servizio, ne citiamo un paio dei quali abbiamo riferimenti precisi.
Quello che segue è semplicemente [si fa per dire] un contatto della coda con la pista. L'incidente conferma certamente i problemi di manovrabilità dell'aeromobile in fase di richiamata ma pone la necessità di un accurato ed approfondito intervento di ispezione alla struttura e di conseguente manutenzione.
Infatti, non va dimenticato che l'MD11 FedEx subì un contatto della coda in un volo precedente. Dal Final Report dell'incidente di Newark:
The airplane also sustained damage from a tailstrike during a bounced landing at Anchorage, Alaska, on November 4, 1994, when a 2.59 positive g load was applied to the airframe during the second touchdown. FedEx maintenance documents indicated that the tailstrike had damaged the airplane’s aft fuselage skin, a rear bulkhead, and several floor supports.
La segnalazione che segue è stata ripresa dal sito dell'Air Accident Investigation Branch UK.

The aircraft suffered a tailstrike on landing from a visual approach to Runway 05 at Cambridge. The weather was good and the surface wind was 090°/5 to 7 kt. The usable landing distance beyond the threshold is 5,735 feet. A major amount of the debris from the tailstrike was found between 1,350 and 1,550 feet from the threshold.
The commander reported that the approach was stable but when he started to lower the nose after touchdown the pitch attitude increased rapidly. He was unsure whether the aircraft was still on the runway and, as he considered the runway too short to recover from a 'bounce', he applied power and went around. It was his opinion that this was the point when the tailstrike occurred. The subsequent landing was uneventful.

Scheduled 14 CFR - Part 129 operation of Foreign Carriers
ALITALIA Accident occurred Friday, August 19, 1994 at CHICAGO, IL
Aircraft:MC DONNELL DOUGLAS MD-11F, registration: IDUPO
Injuries: 267 Uninjured.
The airplane experienced a hard landing on initial touchdown. subsequently, the nose tires failed, damage occurred to the general area of the nose landing gear support structure, and there was foreign object damage to the #1 and #3 engines. The flight data recorder (FDR) data indicated that the initial touchdown acceleration had a value of 1.9488 g's. At that time, the throttle resolver angles indicated 52.03, 51.33 and 49.22 degrees for the number one, two and three engines, respectively. Also, the FDR revealed that after touchdown, the airplane experienced four oscillations in the pitch axis. The maximum pitch angle during this time was +5.98 degrees nose up, and the minimum value was -2.46 degrees nose down. during this time frame, spoiler positions never exceeded 8.0 degrees of deflection and the nose weight on wheels parameter changed four times.
The National Transportation Safety Board determines the probable cause(s) of this accident was:
The First Officer's improper flare and improper use of flight controls during the landing flare/touchdown.

Gli incidenti in atterraggio di questo aeromobile sono stati quasi sempre attribuiti al comportamento del pilota: improper handling, improper landing technique. C'è stato sempre qualcosa di inappropriato. Ancora dal Final Report del FedEx 14 accident:

Nel caso del CAL 642 il comandante era stato addirittura parte attiva di un simile programma di addestramento e ciò ha forse contribuito a far in modo che la sua tecnica di pilotaggio poco prima del contatto con la pista di Hong Kong fosse la migliore possibile, almeno tale da non consentire di attribuirgli comportamenti impropri. E poi c'è stato il wind-shear e l'aeroporto di Hong Kong ed ecco che l'aspetto politico-industriale-economico si insinua nel processo dell'investigazione per mantenere velato al grande pubblico il fattore causale di fondo. La macchina.

La conclusione di queste vicende è che la linea di produzione dell'MD11, assorbita con la McDonnell Douglas da Boeing, ha chiuso definitivamente l'esercizio e che molti esemplari di questo aeromobile verranno riconvertiti in allestimento merci.