HKSAR v. PAUL Y CONSTRUCTION & ENGINEERING CO LTD AND ANOTHER

HCMA 161/2007

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

MAGISTRACY APPEAL NO. 161 of 2007

(On appeal from TWS108-111 of 2006)

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JUDGMENT

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1.  This is an appeal from a magistrate who convicted the two appellants each on two summonses. Notice of appeal against the sentences imposed was also given but leave was granted to abandon those appeals on the hearing date. At the hearing of the appeal judgement was reserved, which I now give.

2.  On 7 July 2005 a tower crane, which had been erected at a construction site in Kwai Chung, New Territories, collapsed whilst being operated.  The crane had been manufactured by a French company "Potaine" and was of model number MD 235A.  The operator’s cabin, situated high up on the structure, plunged to the ground: the operator was killed.  Staff from the Labour Department attended the scene shortly after the incident. 

3.  As a result of investigations two summonses were issued against each of the two appellants: one summons against each alleged failure to ensure that the tower crane was not used unless it was of good mechanical construction, made of strong and sound materials and free from patent defect whilst the other summons against each appellant alleged that it had failed to ensure that the tower crane was not used unless it was (sic) properly maintained. The summonses were issued pursuant to regulations framed under the Factories and Industrial Undertakings Ordinance, Cap 59, relating to lifting appliances and lifting gear. 

4.  It was admitted that the first appellant was the principal contractor responsible for the construction site in question;  the second appellant was a subcontractor on that site;  each was an owner of the tower crane.

The construction of the tower crane

5.  The upright, or mast, of the tower crane comprised a number of sections erected on top of one another.  The sections of the mast were made up of four upright square hollow tubes which were cross-braced at intervals.  The base of the mast was located in the basement of the construction site.  In the basement, embedded in concrete, were four square, hollow tubes, known as fixing angles.  When a tower crane is erected the fixing angles are first embedded in the concrete and the lowest section of the mast is then assembled on top of them: after a tower crane is dismantled the fixing angles remain embedded in the concrete and are sacrificed.

6.  To secure the lowest section of the mast to the fixing angles and to secure a higher section to a lower section of the mast a rectangular steel insert, drilled with four holes, is placed inside both the fixing angle/lower section and the section above: this item is known as a fishplate.  The holes drilled in the fishplate correspond with holes in the square hollow tubes: two at right angles to one another in the upper section and two at right angles to one another in the fixing angles/lower section.  Sections of steel rod, known as locking pins, are then driven into the respective holes ensuring multi-directional stability.  Two different shapes were in use at different joints between the sections, tapered locking pins and cylindrical locking pins. This is the system used on each of the four sections of the square hollow tube resulting in a total of four fishplates and 16 pins being used in each join between the sections. 

7.  For the sake of completeness I would note that there existed a distinction between the join involving the fixing angles and all other joins: however, in the present matter as it was the failure of pins in the join between the fixing angles and the bottom four square hollow tubes of the mast, or “legs” as I shall refer to them perhaps colloquially, which led to the collapse of the tower crane.

8.  Each of the legs of the tower crane was identified in various reports according to its location by reference to cardinal points of the compass.  Each of the pins in each leg was assigned an initial letter corresponding to that point followed by another letter which appears to have indicated the level at which it was located, “B” being used for the join in basement and "P" being used for a higher join at podium level. This was followed by a digit, the digit "1" being assigned to the two pins in the fixing angle/lower section of the legs and the digit "2" being assigned to the pins in the upper section of the legs.  The respective two pins in each of the upper and lower sections of the fixing angles/legs were further identified by being assigned a suffix of either "V" or "H" depending upon whether its position was vertical or horizontal to that of the viewer.  Thus “NB2H” referred to a pin in the North leg, at basement level, in the upper half of the fishplate and viewed horizontally from the point of view of the viewer.

9.  It is not in dispute that when the site was inspected by staff of the Labour Department parts of pins NB2H and NB2V were found on the ground at the base of the North leg.   Two parts, comprising the whole, of pin NB2H were found but only one part, less than the whole, of pin NB2V was found.  The remaining part of pin NB2V has never been found.  It is not in dispute that it was the failure of these two pins which caused the tower crane to become unstable and to collapse.

The contentions

10.  The magistrate, in a clear and concise, yet comprehensive, statement of findings summarised the contentions of the prosecution in these terms:

It was the prosecution’s case very basically that the tapered locking pins used in the lower mast were not original Potaine locking pins, and because of the grade and treatment of steel used they had both formed a crack on the sides of the length of the pin during normal use of the crane. These cracks had spread across the face of the locking pin by fatigue resulting in a total facture of the pin.  Thereafter the two parts of each broken locking pin worked their way out of their sockets and fell onto the ground.  It was the final falling out of place of the locking pins that resulted in the collapse of the tower crane. If there had been proper maintenance of the locking pins involved this problem would have been found and the accident avoided.

and those of the defence thus:

The defence case was that the crane designer had built a latent defect into the base mast locking pins by using locking pins with  machine marks on them, which had microscopic cracks at the machine mark. This was a well-known phenomenon. These cracks became larger due to the movement of the crane and thus by fatigue eventually causeda completely fracture of the locking pin.  It was also the defence case that at the moment of complete fracture (ie the ligaments broke) it caused the crane to lose its stability and as a result it fell, and at this moment a huge elastic force was created and this caused the locking pin head, which was missing, to be catapulted out of its position and that was why it could not be found after the collapse.The defendant further maintained that the grade and treatment of steel used was suitable for use in the lower mast of the tower crane. The defence also relied upon, inter alia, the crane examinations and maintenance schedules to show the crane had been maintained in “in an efficient state, in efficient working order and good repair” as defined in the Regulations.

11.  The magistrate dealt in summary with the evidence of each of nine prosecution witnesses and two defence witnesses who testified before him as well as clearly indicating which portions of the evidence of each he accepted or rejected and providing reasons for doing so. 

Expert witnesses

12.  Each of the prosecution and defence also called one witness whom the magistrate accepted to be an expert in metallurgy. The magistrate accepted the evidence of  Professor Wu, the prosecution expert, but did not accept that of the expert called by the defence, Professor Lai, where there were differences in the opinions or conclusions expressed by them.  He dealt with their evidence at some length, clearly identifying the areas where their opinions differed insofar as they related to the findings of fact which it was necessary for him to make.  He was fully entitled to take the approach he did in regard to their respective testimonies and, as a consequence, to make the findings which he did. He provided cogent reasons for making those findings.

13.  The evidence of the expert witnesses fell broadly into two areas: first, what it was that caused the tower crane to become unstable and to collapse and, second, the suitability of the grade of steel used in the tapered locking pins.

14.  It is helpful to extract from that section of the statement of findings which deals with the expert evidence, commencing with the magistrate’s conclusions regarding the collapse of the tower crane:

(l)	I was impressed with Professor Wu, who was called by the prosecution. I found he was an honest and reliable witness and an expert in metallurgy and I accepted his evidence.  I also accepted that parts of his evidence were based on his experience as an expert and not upon any specific tower crane experience.  I also accepted there was to some extent an element of speculation upon what actually happened in the final collapse of the tower crane, but found this speculation was supported by evidence, which I found was proved beyond reasonable doubt.  I therefore found that I could accept his explanation for the crane’s collapse.
(m)	I also found that Professor Lai, who was called by the defence, was  an expert in metallurgy, but I rejected his evidence when it conflicted with Professor Wu.  I found Professor Lai’s opinion was largely based on the premise that there had been a crack already introduced into the base mast locking pin by the machining and this had become enlarged by reverse bending fatigue so that it spread across the face of the fracture.  He opined therefore that any composition of the metals discussed would have surcomed (sic) to this complete fracture.  I found, however, that I had serious doubts there was any such machine mark cut, even a microscopic one, introduced into the base locking pins in this case. I also found there was no examination of any other pins with the same steel properties, same machine mark and same origin to discover if such was present. I therefore believed that the cause of the fracture was to do with the metal and its treatments that had been used for the base mast locking pins in this tower crane, which had allowed such cracks to newly form during use of the crane.
(n)	I found as a fact that Potaine locking pins were not used in the base mast of this crane...
(o)	I accepted Professor Wu’s evidence that he saw from the photographs taken at the scene about 4 hours after the accident that there was substantial rusting over the fracture face of the broken base pins and … that when he physically examined the fracture faces of the broken pins he also found that there was a single colour over the whole fracture surfaces of both broken pins ...  I accepted his belief that the rusting on the fracture surfaces would not have rusted to such an extent in just a few hours after the collapse and during the delay in the examination by him…
(p)	I found that there had been a reverse bending fracture of the two lower mast locking pins used in this case caused by fatigue …  This reverse bending eventually caused the small cracks to spread across the face of the pin in a straight line reaching the stage of a final ligament. This small final ligament eventually broke after sustaining static loading. Thereafter, because of the small rocking movement of the crane caused during its operation and because of the tightness of the tapered locking pins in the base mast after hammering into place, the broken locking pins gradually worked their way out of their holes, whilst in the meantime they were able to still hold the mast in place because the stress was taken by the fishplate and lower mast ….  I found this working out stage of the locking pins after complete fracture took a number of days to happen.
(q)	I found it was proved that the working out of the base pins took a number of days because I found
	(i)	the fracture began after the crane’s errection and the weight testing;
	(ii)	the tapered locking pins were hammered tightly into place and thus movement was restricted ;
	(iii)	it was the head of the broken pin NB2V that was missing (I accepted Professor Wu’s evidence that it would be the head that moved out first);
	(iv)	the final resting place of the broken locking pins, except the missing piece, was beside the North leg after falling out,
	(v)	the rusting over the fracture faces on the broken locking pins found was uniform and substantial;
	(vi)	because I found that the broken locking pins were supporting the tower crane until they had completely left the frames;
	(vii)	I believed the collapse had begun by the North tower crane leg mast sliding out of its fishplate and not by a dynamic breaking of that part;,
	(viii)	because I rejected the assertion that the missing piece of NB2V had been catapulted out as Professor Lai opined;
	(ix)	I found instability of the crane was caused last.
(r)	…
(s)	…
(t)	I further believed that because of the poor lighting conditions in the basement the missing part of NB2V was unknowingly removed from the North leg area some time before the collapse …
(u)	I accepted Professor Wu’s evidence that the stress on the fracture area was low stress during normal driving of the crane and that the crane mast had been subject only to mild loading. This point, I accepted, was proved by the small ligament left on the broken locking pins. I further accepted that it had therefore required a large number of the bending cycles to take the initial cracks to the final fracture stage.I accepted this could have taken in the order of months, as I believed the crack would widen slowly given the low stress and small movements involved. I found that this whole process had started after the weight test in September 2004 carried out by PW3.

15.  The magistrate also dealt in some detail with the type of steel that was used in the manufacture of the tapered locking pins, the disagreement between Professor Wu and Professor Lai as to the suitability of the respective grades of steel and their opinions as to which was preferable.  The real relevance, in my judgment, of this evidence lies not so much in the nature of the difference but in the fact that the pins were of different grades of steel. 

16.  When looking at what the magistrate said it is also worth recalling that the two experts were in agreement as to the grades of steel that had been used in respect of the failed locking pins. Professor Lai went further than did Professor Wu and established that that same grade of steel had been used in respect of all 16 of the tapered locking pins for the joins between the fixing angles and the legs of the tower crane as well as those fishplates.  It was also common cause between the two experts that the locking pins used at the join at the podium level were made of 34CRMO4 grade steel whereas the locking pins used at the basement join, where the failure occurred, were made of medium carbon steel.

17.  The magistrate found, as he was entitled to do on the evidence before him, that the pins which failed were unsuitable for the task, expressing his reasons in the following terms:

(w)	I also accepted Professor Wu’s opinion that the broken pins NB2H and NB2Vwere made of ferrite/pearlite steel of medium carbon plain carbon steel…I also found these … locking pins did not meet well-documented international chemical standards of 34CRMO4 grade steel. This I found was a major difference between NB2H and NB2V and the podium locking pins NPH and NPV. I also found that fishplates NB and SB (basement fishplates) were of the same material as the broken locking pins.
(x)	I found that locking pins NB2H and NB2V had a far less hardness value than the podium locking pins NPV and NP2H. I further accepted Professor Wu’s opinion that the broken pins were not hard enough for the job they were to perform...
(y)	… I further accepted Professor Wu’s opinion that NB2H had a higher propensity towards earlier fatigue fracture formation than the podium-locking pin NPH. I also accepted his evidence that there was a trade off situation between elongation and strength and this accounted for the minimum elongation being defined in practice, and by so doing the manufacturer could find ways to meet proof strength by carrying out appropriate heat and cooling treatments.
(z)	I also accepted Professor Wu’s opinion that leaving aside the chemical components of 34CRMO4, he believed that a proof strength of 403mp and an ultimate tensile strength of 633mp were not sufficient for a base mast locking pin and that 600mp and 800mp respectively were the requirements for such locking pins. I found that even Professor Lai conceded that such requirements were very high and would only normally be used for good reason. I found that the base mast locking pins for this tower crane were limited in diametrical size as part of the crane’s design feature and I therefore believed that an unusually strong material with high proof strength and ultimate tensile strength was required for the job to enable such smaller diameter of pins to have the safe strength for the job.
(aa)	I accepted Professor Wu’s explanation that 34CRMO4 … was an international standard for metal … that Chromium and Molybdenum were added to Carbon steel to increase strength whilst at the same time retaining ductility. I found that they were then subjected to heat and cooling treatments to obtain the proof strength required.  This I found made the steel more expensive.
(bb)	I also accepted that as a general rule it was better to use a material with high strength to prevent fracture provided that ductility was at least normal, as in 34CR MO4, even though it was more brittle. I accepted that some untreated medium Carbon steels may be better than 34CRMO4 for ductility, but I found that they did not satisfy the strength requirement and their resistance against fatigue and rust was lower. In this respect, I rejected Professor Lai’s opinion that ductility was more important than strength in this case.
(cc)	I also accepted Professor Wu’s opinion that the revealed chemical components of the fractured locking pins were to be blamed for the fracture occurring and I rejected Professor Lai’s assertion that medium Carbon plain Carbon steel was appropriate for this crane on basis it was commonly used for shafts and fishplates, even if it was normalised.
(dd)	…
(ee)	I also accepted Professor Wu’s opinion that a crane designer would be very aware of the loading conditions, stresses and material specifications of a tower crane when deciding on the base mast locking pins to be used... I found this finding was supported by the fact that there had been no known collapse of any other crane made by this French manufacturer of this design worldwide…. I also found it inconceivable that an international company like Potaine with a worldwide reputation in tower crane manufacturing would not have used qualified engineers … when designing their tower crane’s locking  pins.  In this respect, I rejected Professor Lai’s suggestion they could have made an error and left a latent defect present.
(ff)	…
(gg)	I rejected the opinion by Professor Lai that the normalised medium Carbon, ferrite/pearlite, steel that was recommended for shafts was the correct choice for these base mast locking pins and was better than 34CRM04, as I believed shafts were for drive purposes and would not have to undergo the same stresses as the base pins in this case.
(hh)	I also accepted Professor Wu’s opinion that the small taper on podium pins, which I found was not a very small step machine mark, would not have caused the stress concentration to become so high that it would have been a significant contribution to any cracking.  In this respect, I also rejected Professor Lai’s opinion that the tapering on base locking pins used in this tower crane had introduced a crack, however small, and this had been to blame for the reverse bending cracking. … I also believed that if this were a genuine belief in this case Professor Lai would have done at least some basic testing to determine whether such machining cracking was present on the unbroken pins that met the 34CRMO4 criteria, but he did not.
(ii)	I found … pins NB2H and NB2V … were not manufactured by Potaine as they were different in, inter alia, metal content, heating and cooling treatment and machine design.
(jj)	I accepted that the metal content of locking pins, one of 34CRMO4 and the other of medium Carbon plain Carbon steel, could not visually be seen apart, and I also accepted that a cracking in the length of a locking pin might not be visible to the naked eye on inspection. I also accepted that in this case ultra sonic testing was the only way to determine cracking once the base mast locking pin was in position, and that any such testing required an expert operator and was not normally undertaken on tower cranes.

The magistrate's findings

18.  The magistrate then went on to set out his concluding findings based on the facts he had found proved in this manner:

(1)	The basement locking pins were made of medium Carbon plain Carbon steel and treated to become of a Ferrite / Pearlite structure, and not Martensitic. They had not undergone such heating and cooling treatments to make them strong enough for the base mast of the tower crane.  They were therefore unsuitable for the task.
(2)	The locking pins … suffered a reverse bending fatigue fracture after erection of the crane and after weight testing.  This took place over a period of months and finally caused a complete fracture of both [pins].
(3)	The missing head part of pin NB2V fell out of its socket days before accident and had been removed from the leg area.  The other broken pins had also been working their way out of their sockets for many days before the collapse and eventually fell out shortly before the collapse onto the ground beside the leg.
(4)	The Code of Practice for daily inspection was not performed as required so as to discover such happenings above.
(5)	As a result of (1) and (3) above the crane was not in good mechanical condition, it was not made of strong and sound materials and it was not free from patent defect at the time of collapse.
(6)	Maintenance was not carried out properly and allowed the defects in (3) above to exist for a number of days before the collapse when they were clearly observable upon proper inspection.
(7)	For the reasons given, both the tapered pins … were not manufactured by Potaine but were manufactured in China and supplied by Moreten Engineering Co.
(8)	Locking pins NB2H and NB2V were substandard only in relation to their use as base mast locking pins in the base of this tower crane as they lacked hardness, they had a lower proof strength and lower ultimate tensile strength (whilst maintaining sufficient ductility) given the diameter of the locking pin design, than was necessary for a locking pin required in this position.
(9)	I found the base mast locking pins were not clearly marked as advised by the Code of Practice.
(10)	I found by irresistible inference that by ordering and using tapered base mast locking pins that had been made in China, which the defendants knew were not supplied from Potaine and which they knew had no certification from Potaine of suitability for this tower crane, the defendants had taken a substantial risk that the locking pins used in the base mast section might not be strong enough and suitable for the specialised job in the base of the crane.
(11)	I found the defendants had taken this risk despite the advice of the Code of Practice in relation to the use of non-original manufactured locking pins for this task.
(12)	I rejected the assertion that Potaine made base mast-locking pins were designed with a latent and non-detectable design fault at the machine mark.  I also rejected the assertion that a crack would have been initiated in such Potaine locking pins under their designed use at the base of the crane.
(13)	I found that there had been failure by D1 and D2 to seek confirmation by Potaine that the Chinese made tapered base mast locking pins to be used in the base of the tower crane were suitable for such use.
(14)	I found the defendants failed to notify a competent examiner that non-original Potaine locking pins were being used in the base of the tower crane when he carried out his safety inspection.

19.  The magistrate also found, correctly, that the summonses related to offences of strict liability.  He went on to find that the prosecution had disproved, beyond reasonable doubt, the “defence of due diligence” in respect of each of the four summonses.  Whether that defence is available in respect of offences under these regulations seems to me to be arguable: the decision to which the magistrate made reference, A.-G. v FONG Chin Yue and Others (1995) 1 HKC 21 dealt with offences under the Dutiable Commodities Ordinance.  In Paul-Y ITC Construction Ltd v HKSAR [1998] 2 HKLRD 35 the Court of Appeal found that such a defence was available under the Noise Control Ordinance (Cap. 400) but each of those Ordinances is well removed from the present regulations which are concerned with public safety.

20.  That is not in issue I have to decide.  The availability of the defence was not a matter which was argued before the magistrate or before me. Even were it unnecessary for the magistrate to make such a finding the fact that he did so is to the benefit of the appellants: they cannot sensibly make any complaint about it albeit that he may resolved the issue against them. 

The grounds of appeal

21.  Once again, this is an appeal from a magistrate which has been prosecuted on the fundamentally erroneous basis that the magistrate made an unjustifiable finding, therefore the appellant is entitled to succeed – ignoring entirely the provisions of sec. 119(1)(d) of the magistrates Ordinance, Cap. 227 and the decision of the Court of Final Appeal in CHOU Shih Binh v HKSAR [2005] 1 HKLRD 843.  It is also an appeal which has been prosecuted on the discredited basis of trawling through a transcript of the proceedings in order to find a phrase or paragraph which, ignoring the evidence as a whole, is held up as demonstrating the magistrate’s fallibility.

22.  Two perfected grounds of appeal are advanced.  The first was a challenge to the finding that the two locking pins had become completely detached over a period of days prior to the collapse of the tower crane, the contention being that the magistrate

a)	wrongly relied on a speculative theory advanced by the prosecution expert, such a theory being conceded by him to be speculative, it being equally possible in his opinion that the pins had not visibly moved at all until the time of collapse.
b)	wrongly relied on other inconclusive scientific theories presented by the prosecution to support the above finding, whilst rejecting without good reason or adequate explanation the defence expert evidence
c)	wrongly reached consequential findings of guilt based on the above erroneous conclusions.

- essentially, then, a complaint that the magistrate accepted the evidence of the prosecution expert but not the defence expert.

23.  The second ground of appeal contended that the magistrate had erred in finding as a fact that the appellants had ordered and used locking pins manufactured in China in that

a)	he had failed to distinguish the respective roles and status of the defendants in that D1 was never involved in the purchasing of the crane or its parts and, consequently could not be expected to have the same knowledge nor consequential obligations and D2;
b)	such a finding was in any event contrary to the evidence;
c)	wrongly rejected DW3’s evidence without proper basis or through faulty reasoning;
d)	such a finding was based on the reasoning that the defendants had not purchased any replacement pins from Potaine or the local sole agent, but ignored the fact that the defendants had an ample supply of original pins and had no need to purchase replacement pins;
e)	by such erroneous finding he reached a consequential wrong conclusion when applying the due diligence test laid down in Fong Chin Yue but in any event as far as D1 was concerned, by virtue of D1’s different status, role and state of knowledge, also applied the wrong facts to the test.

24.  It was quite clear from the statement of findings that the magistrate was very much alive to the issues which he needed to consider. 

Ground one

25.  In regard to the first ground, Professor Wu’s opinion was "speculative" only in the sense that it was an opinion which he had expressed as he had not been present at the time of the collapse of the tower crane and was obviously unable to say with complete certainty precisely what had led up to that collapse: he expressed that opinion based upon his experience, observations, and scientific principles.  What is described as a concession on his part was a sensible acceptance made by a responsible expert witness which did nothing to undermine the validity of the opinion he expressed. 

26.  The totality of the evidence supported the opinion which Professor Wu expressed.  One particular aspect, in my judgement, may almost be regarded as definitive and that was the rusted condition of the three located portions of the failed locking pins: Professor Wu’s evidence regarding this aspect of the matter is compelling whilst that of Professor Lai is untenable.  It was Professor Wu’s opinion that that rusting would have occurred over an extended period of time and not had the failure occurred on the day of the incident.  The condition of those portions of the failed locking pins coupled with Professor Wu's evidence leads to the irresistible inference that the failure of the pins had occurred sufficiently in advance of the collapse of the tower crane for that failure to have been detectable. 

27.  Further support for this, if any be needed, is to be found in the fact that the head portion of pin NB2V was never located.  Officials from the Labour Department arrived at the scene within about two hours of the collapse of the tower crane, searched the area surrounding the tower crane but were unable to find the missing head portion of the pin.  The magistrate was entitled to accept Professor Wu’s opinion - which, it has to be said, accords with common sense - that, contrary to Professor Lai's opinion, the head of pin NB2V would not have been catapulted out of its socket.  

28.  The inference to be drawn is that the head of the pin had earlier been ejected from its socket and removed - presumably inadvertently - from the basement.  The consequence of that is that the hole which it had previously filled would have been noticeable upon a proper visual inspection of the base of the crane: the fact that that visible hole would have indicated that the pin that, or a portion of it, was missing constituted a patent defect.

29.  There is no merit in the first ground of appeal.

Ground two

30.  There are effectively three aspects to the second ground of appeal: first, the finding that substandard pins had been used in the basement join; second, that those pins had been purchased other than from Potaine; and, third, the failure to distinguish between the roles of the two appellants.

31.  It is unfortunate that, for whatever reason, the prosecution did not lead admissible evidence, of any specifications established by Potaine in regard to the grade of steel to be used in respect of the locking pins for that would have been definitive.  The failure to lead that evidence is not fatal to the prosecution case. 

32.  The issue was ventilated during the trial, but in a somewhat different context.  It was clear from the evidence that those specifications were not made known until after the accident: for this reason the magistrate rejected a portion of the evidence of PW3 and PW5 who had testified that they had known for many years before the incident that all original locking pins were made from 34CRMO4 grade steel.  Although there were two documents before the magistrate, Exhibit P13 and Exhibit D3, which contained references to specifications both as to composition of the steel as well as to stress and breaking strains the magistrate rightly recognized that that evidence was not admissible as it was hearsay.

33.  Given that there is no evidence as to the specifications relating to Potaine original pins, the issue is whether it has been proved that substandard pins were used and that those pins had not been obtained from Potaine but from another source. 

34.  As to whether the pins were substandard, it is common cause between the expert witnesses that the 16 locking pins used in the basement level join were manufactured from medium carbon plain carbon steel and not 34CRMO4 steel.  The magistrate's reasons for reaching the conclusion that those pins were substandard appear at paragraph 16 above and were based upon his acceptance of Professor Wu's evidence: that evidence was that they were substandard in the sense that they were not suitable for the task to which they were put, not substandard simply in the sense that they did not comply with Potaine's specifications.  I do not propose to repeat either the magistrate’s conclusions or his reasons for accepting Professor Wu’s evidence for they were plainly correct.

35.  In regard to the issue of whether the pins which failed had been obtained from Potaine as genuine Potaine products, notwithstanding the grade of steel from which they had been manufactured, the appellants point to the evidence of DW3, CHUI Kwok-fai, a godown employee of the second appellant to show that the appellants owned not only one but six Potaine MD235A model tower cranes as well as 11 other Potaine cranes of a different model or models.  The appellants contend that the evidence of this witness causes a doubt as to the necessity for the appellant to have obtained replacement pins at all, whether from Potaine or any other source.  The concept underlying this contention is that if all six of the MD235A model cranes were not in use simultaneously then there would be sufficient locking pins available from those cranes not being used. 

36.  The relevance of this evidence is said to be that it negates the testimony of PW4, the district sales manager of Potaine's local agent, Manta Engineering and Equipment Co Ltd, which was that since it had sold the tower crane to the second appellant in May 1998 no new locking pins had been purchased from or supplied by Manta.

37.  What the appellant’s contention ignores is the acceptance by the magistrate of the evidence of

31.1	PW4, that although Potaine had sold crane designs to Sichuan Machinery Company in the 1980s the MD235A model was not included in that sale (it only having come into existence subsequent to that sale), and, further, the locking pins in respect of the crane designs sold by Potaine were of a different design; and
31.2	PW5, a Superintendent of Morton Engineering Company which had supplied the very fixing angles for the tower crane in question in August 2004 together with four locking pins per fixing angle, his evidence being that the fishplates and locking pins had been manufactured in China.

38.  It is pertinent to observe that in regard to the evidence of PW5 the magistrate rejected those aspects of his evidence in which he claimed that the locking pins had been made of 35CRM04 grade steel and that he knew the specification prior to the accident.  That rejection was obviously correct given the evidence of Professor Lai that all 16 of the locking pins used in the basement join involving the fixing angles were manufactured from medium carbon plain carbon steel and the evidence that the specification of the locking pins was only made known after the date of accident.

39.  The evidence of DW3 in regard to the fixing angles and pins is, at the very least, confused as may be seen from these extracts of his evidence in chief:

Q : Were you aware that the legs or fixing angles for that crane were not of the same manufacturer as the rest of the crane?

A : Yes, I know.

Q : And those legs, do you know where they come from?

A : Well, from Sichuan of mainland China.

Q : Did they have their own pins or not?

A : No.

Q : Where did those pins come from?

A : Eight pins come together with the fixing angle

Q : And those pins that come with the fixing angle, had they come from the same manufacturer?

A : Yes.

then, later

Q : How can you be sure that all pins that you provided for this crane were Potaine or French pins?

A : Because all pins come together with the tower crane and the fixing angle, so I am very sure that all of them comes from France

Q : From the time that the crane had been bought, together with its original pins, in any of the pins needed re placing?

A : Some part of them were discarded, but we hadn't had the need to buy new pins

and later again

Q : ... what is distinctive about this style?

A : Taper.

…

Q : Do you know if Paul Y Plant Hire has ever bought any pins... for this type of Potaine crane from any other manufacturer?

….

A : We never bought anything from others.

40.  A matter of note is that when DW3 was asked, during evidence in chief, what was distinctive about the style of locking pins purchased from China he replied, whilst holding Exhibit P11, "Taper" yet when he was asked, specifically, in cross-examination whether the "Chinese pins" were tapered or not he unequivocally replied "No".  In re-examination he was asked what were "…Chinese parts, as far as pins are concerned" to which he replied “straight pins”.

41.  It is hardly surprising, in the circumstances, that the magistrate was unimpressed with DW3 as a totally honest and reliable witness.  He gave cogent and compelling reasons for accepting or rejecting different portions of this witness's evidence.

42.  There is consequently ample evidence that, especially, the locking pins but also the fixing angles and fishplates which were used at the base assembly of the collapsed tower crane had been purchased from China which leads to the irresistible inference, particularly in the light of the evidence of PW4, that they were not Potaine original equipment. 

43.  The contention that the magistrate ignored the different roles of the two appellants does not take cognizance of the provisions of regulation 3(1) and 3(2) of the relevant regulations.

44.  There is no merit in the second ground of appeal.

Decision

45.  In the circumstances, each of the magistrate's conclusions was fully justified on the whole of the evidence before him.  My views accord entirely with his: I do not propose to repeat the same conclusions using different language.

46.  The appeal of each appellant against each conviction is dismissed.