TSANG CHI KO v. MENZIES AVIATION GROUP (HK) LTD AND ANOTHER

HCPI 129/2003

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

PERSONAL INJURIES ACTION NO.129 OF 2003

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J U D G M E N T

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The accident

1. 14 July 2001, seemed to be another working Saturday for the plaintiff Mr Tsang Chi Ko.  He was an Operation Load Control Officer of the 1^st defendant Menzies Aviation Group (HK) Ltd (“Menzies”).  After a good breakfast he started his morning shift at 5 a.m.  On that day, he was assigned to work for the Northwest plane parked at Bay 35 in the Hong Kong International Airport of the 2^nd defendant.  He prepared all the freight information for that plane and went to Bay 35 to deliver the same to the pilot.  Since the pilot had not arrived, he left the documents in the cabin for the cockpit crew to peruse.

2. Then he left the cabin and stepped onto the aerobridge for passengers, which was connected to the cabin and left the aerobridge through an exit door in the aerobridge specially for ground work attendants.  When he was on the outside platform and reached the top of the staircase leading to the apron and was about to descend, he fell down the staircase and suffered serious injuries.

3. Why did he fall down the staircase is the main issue to be tried in this case.  According to Mr Tsang he said that the aerobridge suddenly lowered down rapidly, i.e. fell down suddenly and vibrated vertically.  This caused him to lose balance and his whole body slid down from the top of the staircase and fell down along it for 2 metres until he was about 4 metres plus above the ground, i.e. in the middle of the staircase.  He felt pain in the head, neck and back and waist and lost consciousness.

4. The defence contended that Mr Tsang fell down not because the aerobridge moved or fell suddenly.  He fell down because he was not careful himself and slipped and fell down from the top to the middle of the staircase by 2 metres.  He could not hold the handrail because he was holding the intercom radio by his right hand and when he fell down his left hand did not hold on to the handrail.

5. That was about 7:30 a.m.  A Northwest Airlines maintenance staff found him and reported to Menzies office for the ambulance.  The one who received this message was one Chau Wai Lam, one of Mr Tsang’s colleague.  He immediately went to the scene and found Mr Tsang lying down about half way up the aerobridge.  There were other people around including Northwest Airlines and first aid staff.

6. When Mr Tsang came around on the staircase, Mr Ko Wah Fung was also there.  Mr Ko was the airfield officer of the Airport Authority.  He arrived at the scene of the accident after he received the report that someone was injured on the staircase.  He heard Mr Tsang saying that he had slipped down the staircase and he complained of pain to his neck and waist.

The issues

7. The first issue is : Did or would the aerobridge move or fall suddenly?  Secondly, could it fall suddenly?  The first question is a question of fact by considering the evidence of all the witnesses from both sides.  The second question is a scientific question for the experts.  Dr Cheung Kie Chung of the Hong Kong University said it could.  Mr Bill Stemmons, called by the defence, said it could not.  Their evidence will be considered after the consideration of all the witnesses of fact.

Did the aerobridge move and cause the accident?

8. As aforesaid when Mr Tsang came around after a few minutes and regained consciousness, he did not say anything about the movement of the aerobridge.  He said he slipped and fell down.  However if one discarded what Mr Tsang said immediately after he came around on the ground that he just regained his consciousness and therefore could not recall clearly what actually happened, one would then consider what he said on several occasions after the accident about how he fell down the staircase.

9. Two days later, a Manager of Ramp Operations compiled an Incident Report for Menzies.  It was said that :

“Jungle [i.e. Mr Tsang] was assigned to report duty at 0500 am for NW018 load sheeter.

At around 07:25 he has printed out the flight plan and went out to aircraft to hand those document to NWA Flight Crew by driving the vehicle OAL-00011 with the handheld radio.

After handed the flight plan to NWA Flight Crew (around 07:30), he left the aircraft and return to apron to take his vehicle.  Once he made the left turn to the staircase and ready to step down.

He has slipped and fallen down from the top and stopped at the middle (around 2m).

He can’t hold the hand rail because of he hold the radio by right hand and when he fall down his left hand can’t hold the hand rail.”

10. This Incident Report was compiled by one Gregory Chung at the instruction of Mr Michael Tso Tim Shing.  This was signed by Mr Tso himself after Gregory Chung had spoken to Mr Tsang after the accident in order to find out how he fell.  According to this report, Mr Tsang had not said that the aerobridge suddenly lurched or dropped.

11. Thereafter, on 19 July 2001, Mr Tsang himself made a work

injury report and signed the same himself.  The original Chinese version of his report is as follows :

「工傷報告書

背境： 付責『西北航空』的平衡控制員，每天須付責把机師須要的文件送上机廠內讓他們閱覽

07:25   本人駕駛貨運車由office到西北航空机停機坪35位，沿鉄梯步行上机廠內。放好文件後，沿鉄梯下回停機坪時，不幸滑脚；從梯頂滑下，面向上背向下一直滑下約兩米多後停下。臥在梯上動彈不得，背部、頸和腰劇痛；跟着頭渾昏迷不醒，待救。

 (據同事說：昏迷的情況，直至救護員來施救後才騷醒。)

(Sd) TSANG CHI KO 19 July」

English translation :

“Work Injury Report

Background : Load Control Officer responsible for ‘Northwest Airlines’, necessary to deliver documents to pilot on board aircraft for their review everyday.

07:25 I drove a goods vehicle from office to Northwest Airlines airplane parked at Parking Bay S35, walked up the metal bridge to the aircraft cabin.  After delivering documents, when I was walking down the metal bridge to the apron area, unfortunately I lost my footing, fell down from top of bridge, face up and back facing down slipped down the bridge for approximately 2 meters odd then stopped.  Lying on the bridge and could not move, immense pain on back, neck and waist; and then felt dizzy and lost consciousness, await help.

(According to colleague : lost consciousness, until first aid staff came to assist and regained consciousness.)

Tsang Chi Ko (signed) 19 July”

12. In other words, Mr Tsang, in his own signed report, said he lost his footing and fell down from the top of the bridge.  There was no mention of the lurching or dropping of the aerobridge either here.  Mr Tsang explained that this report was made according to what he had instructed his brother to type out whilst he was still receiving medical care at the hospital.  It was just a report to state that he fell from the staircase for the purpose of claiming employees’ compensation.  It did not occur to him that he had to state clearly how the accident had occurred.  That was his explanation.

13. Further, Mr Tsang met Mr Michael Tso about a month later at the Kai Tak Airport Hotel.  Mr Tsang agreed under cross-examination that Mr Tso wanted to know how the accident occurred and he related the circumstances of the accident to him.  He also handed his written report to him.  He agreed there and then he had not mentioned about the movement of the aerobridge.

14. By that time he had all the opportunities to recall what actually had happened and could inform his employer’s representative formally that his fall was caused by the movement of the aerobridge.  He did not.  It is therefore reasonable to accept the submissions of the defence that he mentioned about the movement of the aerobridge only after the union representatives had advised him of a woman by the name of Miss Vivian Wong who had been injured because of an aerobridge as alleged by Miss Wong.

15. Under cross-examination, Mr Tsang recounted how he came to the conclusion that it must be the movement of the aerobridge after he had discounted other possibilities.  He said he had a good night sleep before and had a good breakfast.  He was wearing a pair of safety shoes provided by his employer.  There was no reason why he would have slipped.  He therefore concluded that the aerobridge must have moved or dropped suddenly and that was the feeling he recalled.

16. However this reconstruction at best is an honest belief that the aerobridge had moved.  This is only an assumption on his part and not an accurate recollection of what actually had happened.  His version is therefore unreliable and should not be accepted by the court on a balance of probabilities.  The next question of course is whether the aerobridge would move.

Would the aerobridge move?

17. The plaintiff call two persons, one Miss Vivian Wong Siu Kam and one Mr Mak Chi Yin.

18. Miss Wong was working with Cathay Pacific.  She recalled an incident on 20 January 2000 at about 10:30 p.m. that night when she was serving a flight parked at Bay 49.  She went back to the aircraft to retrieve a passport for a Korean passenger.  She came back through the aircraft door and walked onto the aerobridge.  She said that the aerobridge suddenly lowered down rapidly and she was like stepping onto the air and therefore missed the floor and lost her balance.  She managed to hold on the inside wall of the bridge and avoided falling down onto the floor.  She hurt her waist and left leg.

19. Under cross-examination Miss Wong however agreed that she could not say whether it was the aerobridge which had fallen suddenly by one foot plus or the aircraft had been raised.

20. Further, Mr Stemmons, an expert called by the defence, who is very experienced in aerobridges, said that if the aerobridge had fallen by one foot, the retractable canopy on top of the connection between the aerobridge and the aircraft could have been damaged by the aircraft door.  However, there was no report of any damage of the door or the canopy.

21. The case between Miss Wong and Cathay Pacific was eventually settled and therefore there is no judicial decision after due process of the law as to whether the aerobridge had fallen as described by Miss Wong.  In any event, the physical evidence suggested that the aerobridge could not have fallen by one foot plus and thereby causing damage to the aircraft door by the retractable canopy connection or vice versa.

22. Mr Mak Chi Yin was a colleague of the plaintiff.  He actually learned about load control from Mr Tsang.  He also testified that he had experienced very often mild vibrations of the aerobridge.  There was one occasion in about the end of 2000 that he had experienced a sudden drop of the aerobridge whilst he was walking on the staircase.  He nearly lost balance but he did not fall down because he was holding the handrail.  He had not reported the incident either to his employer Menzies.

23. Those separate incidents experienced by Miss Wong and Mr Mak could not amount to sufficient similar fact evidence to support the fact that aerobridge would drop suddenly.  The former could not distinguish between the raising of the aircraft and the dropping of the aerobridge.  The latter had not reported the matter to his employer in spite of this frequent experience of the dropping of the aerobridge and thus putting his evidence under certain degree of suspicion.  In any event, he did not fall on the aerobridge and that kind of movement is not the one as described by Mr Tsang which has caused his fall down the staircase.

24. In conclusion, I find that the two witnesses purporting to adduce similar facts evidence are not enough to support Mr Tsang’s version.  Mr Tsang’s own version was quite incredible by his previous inconsistent version when he was given full opportunities to make the allegation on four separate occasions, but he did not.  Such inconsistencies by themselves had already destroyed his own credibility as aforesaid and this could not be saved by the evidence of Miss Wong and Mr Mak.

Could the aerobridge move?

25. One must first of all bear in mind that whether an aerobridge could fall by itself substantially in terms of nearly of about one foot does not mean that the aerobridge did actually fall as described by Mr Tsang.  If Mr Tsang’s allegation of the fall of the aerobridge was rejected by the court, the fact that an aerobridge could fall by itself suddenly would not support his version the bridge did fall.

26. However in this case, after hearing the evidence of two experts, I came to the conclusion that the plaintiff failed to prove that scientifically the aerobridge could fall by itself considerably and cause an accident because of either the bad design, construction or maintenance of the same.  I shall start with the evidence of Dr Cheung.

Dr Cheung

27. Dr Cheung Kie Chung was called by the plaintiff as an expert.  He is with the Department of Mechanical Engineering in the University of Hong Kong.  Since 1992 up till now he has been an Associate Professor in Electro-mechanical Engineering.

28. Dr Cheung opined and postulated a theory as to how the accident of falling of the aerobridge could possibly happen.  In Dr Cheung’s postulation he suggested that the contactors used to supply electricity to the brake and the motor could have been “pitted” because of the oxidation occurred after repeated usage for quite some time.  He said :

“14. It is therefore possible that the contact surfaces are pitted on the day of the accident.  The height of the aircraft was changed and this was detected by the limit switches on the auto-leveller wheel.  The PLC responded to this by energizing the contactor coil (C4 to C6, depending on whether the aircraft had risen or lowered.)  As mentioned in the last paragraph, some contacts may close earlier than the others because of difference in pitting.  The effect is that not of all the four power lines were switched on at the same moment.  Some would be switched on earlier than the others.  Since the brake-release coil is connected to one of the motor power leads, it is possible that the brake would not released a fraction of a second before the motor received power.  There then existed a brief moment during which the aerobridge dropped under gravity.  The motor soon got its supply of power and drove the aerobridge to re-level itself with the aircraft.  It was during that brief duration that Tsang felt the sudden drop and lost his balance.”  [emphasis supplied]

29. Under cross-examination, Dr Cheung corrected himself that the bridge did not fall freely but was driven down by the motor albeit the motor would not be at full force to drive the bridge down to re-level itself with the aircraft.

30. It should be noted that here Dr Cheung has no experience of the aerobridge at all.  He has no experience in the design, manufacturing and maintenance of the aerobridge.  He has not even examined one normal aerobridge.  Although there was an application to examine the aerobridge which had been used for many months after the accident, that application has been refused by me.  The defence stated clearly that no accident whatsoever had occurred after the accident.  Those contactors had not been replaced.  Even pitting occurred by the time of examination, it could not show the condition of pitting immediately before the accident.  For those reasons I have refused the application.

31. Further, all Dr Cheung’s theory was just a postulation, trying to find a possibility of how the bridge could have fallen suddenly and this postulation has not been tested either in situ or in the laboratory.

32. Further, Dr Cheung could not quantify the time gap or time lag when the condition of pitting has caused “a brief moment” during which the aerobridge dropped (or corrected under cross-examination “was driven”) downwards.  He gave an estimation of 150 to 200 milliseconds but that was not supported by any mathematical calculation.  To my mind this is just an educated guess from a mechanical engineer.  In fact, he said it was difficult to estimate the time lag in the delay.  He had mentioned 10 to 20 milliseconds or more and 10 to 100 milliseconds or more.  He admitted that 150 to 200 milliseconds is just an estimation and not calculation.

Mr Stemmons

33. Mr William Leslie Stemmons is an Electrical Engineer since 1969.  Since 1988 he joined Jetway Systems, a manufacturer of aerobridges and he has served as the Principal Electrical Engineer until his retirement in June 2004.  Thus, he has been deeply involved in and is very familiar with the design and testing of aerobridges, designer’s safety standards, quality assurance and compliance with national and international standards, codes and regulations that had the effect of law in both the US and international markets.  In short, Mr Stemmons is extremely experienced in the workings of aerobridges.

34. It is his firm belief from his vast experience that aerobridges would not “suddenly lurch or drop to a lower level or vibrated up or down” as alleged by the plaintiff.

35. There was the distance of clearance between the canopy of the bridge and the plane door and in the case of a Jumbo 747, the distance is about 400 millimetres.

36. Since the plane will be raised or lowered at the time of docking depending on whether it was unloading or loading, there will be automatic adjustment of the aerobridge controlled by the brake-motor system.  When adjudgment is being made the aerobridge is connected to the plane by a set of wheels attaching to the outside wall of the plane and therefore it would not damage the surface of the same.  This bit is so well controlled that it will be moving from a distance of 13 to 30 millimetres maximum.  The rolling up and down distance will be small.

37. He gave a full detail of the vertical adjustment manually or automatically in aerobridges in his report.  He concluded that he considered “it most unlikely that the fall originated with an erratic movement of the aerobridge.  For such to be the case, the bridge would not have been able to function further. …”

38. Further Dr Cheung did not notice that there were two motor systems, one on the left column and one on the right column.  Thus, the aerobridge employs two vertical height reversing contactors for these two column motors.  Mr Stemmons therefore said :

“… If Dr Cheung’s theory were valid, it would have been a phenomenal coincidence, if not a statistical impossibility, that both contactors exerted the same slippage at the same time due to failure of one of the contacts.  If one contactor functioned according to his theory, the offending column would have slipped into rack and as was previously concluded, there were not reports of a rack condition after the incident.” [emphasis added]

39. Thus, Mr Stemmons believed “the rugged construction, the engineering, the spring-loaded nature, the design and metallurgy of these contactors make Dr Cheung’s theory extremely difficult to support”.

40. I accept Mr Stemmons’ conclusion that he “found in the design and construction of these aerobridges a common design for electromechanical lifting mechanisms that comply with all the standards for safe and substantial, lasting, operational reliability”.  Thus, he also considered it “very unlikely that the aerobridge moved in the manner alleged and would have caused this accident.

41. In the end, I find the expert evidence adduced by the plaintiff highly unsatisfactory and it could not prove on a balance of probabilities that pitting would be a cause for aerobridge falling suddenly to the extent as described by Mr Tsang.  I prefer the evidence of Mr Stemmons.

42. From the totality of the evidence as adduced by all witnesses of facts and expert witnesses,  I rejected the plaintiff’s evidence that he fell because the aerobridge suddenly fell as a “roller coaster”, a description used by Mr Tsang on the sensation he felt during his fall.  Obviously, after he has either missed a footing or slid and during the fall from the top of the staircase to the middle of the staircase, he would have a falling experience like riding a roller coaster.  However, it was not because of a roller coaster like movement of the bridge which have caused his fall.

Conclusion

43. I do not accept there is sufficient evidence to warrant a finding that the aerobridge fell suddenly which caused Mr Tsang to fall from the top of the staircase.  Thus, there is no negligence on the part of the defendants nor any occupier’s liability established against them.

44. Accordingly the plaintiff’s action is dismissed with an order nisi of costs to the defendants.  The plaintiff’s own costs shall be taxed according to the Legal Aid Regulations.

45. Finally, I wish to point out that Mr Eric Shum, counsel for the plaintiff has handled the case for the plaintiff very well.  He has presented his case clearly and expeditiously.   The plaintiff should have no grievance against his own team of lawyers who have discharged their duties so competently.

46. I must also thank Mr Cooney and Mr Houghton for presenting a very difficult scientific issue so comprehensively before me.