Evidence of the Air Marshals
133. Sir John Day began his evidence before us with an interesting
and helpful presentation involving 34 slides which are reproduced
in HL Paper 25(i). He explained that the VFR rules applicable
to the flight allowed the aircraft to be flown as low as 50 feet
above ground with a minimum cloud base of 250 feet and minimum
visibility of 1 kilometre.
IFR required the aircraft to be at least 1000 feet above the highest
obstruction en route (Q 280). Sir John reckoned that the
way point change was made some 20 seconds before impact; and he
accepted as facts from the simulation that the groundspeed of
the aircraft at the time of height disclosure was 160-175 knots
with the aircraft in a cruise climb,
and that the crew started to flare the aircraft some 4 seconds
134. In Sir John's view, by continuing a cruise
climb towards the Mull after the way point change, when they could
have selected a high rate of climb, turned away from the high
ground and stayed out of cloud or slowed down and then flown along
the coast, the pilots "grossly breached the rules of airmanship"
(Q 280). Sir John was clear that the gross negligence occurred
at the way point change or a little before but he did not know
when. If as he believed the crew voluntarily climbed into cloud,
"the moment they decided to climb into cloud and go on to
instrument conditions was the moment of negligence, because at
that point they needed to take decisive action to make safety
altitude as quickly as possible or not to fly any further towards
the Mull until they had established that safety altitude"
135. During the course of his evidence Sir John
on more than one occasion emphasised that his conclusions were
based on fact and not on hypotheses. It is therefore appropriate
to look at some of the matters which he treated as fact. (Page
references are to HL Paper 25(i).)
(a) "We know that about 20 seconds
before impact with the ground the crew made a way point change"
(Q 280, p 118 col 1). This figure which derives from the Racal
report on the SuperTANS is based on a power down speed of 150
knots and a straight course from the WP change to impact at that
speed. It is therefore at best an estimate and not a fact since
the only factual evidence of speed at or after the change is the
indication from the ground speed and drift indicator of 147 knots
at initial impact (AAIB report, paragraph 7).
(b) "We know for a fact
four seconds before impact the crew started to flare the aircraft"
(Q 280, p 117 col 1; Q 1088). Not so. The Boeing simulation, using
assumptions now shown to be incompatible, produced this result.
On no view could it be described as fact and there is no evidence
either way as to what caused the aircraft to impact the ground
in the position described in the AAIB report.
(c) "They had chosen to fly straight over
the Mull of Kintyre, and we know that because they had set up
this 1000 feet a minute ROC" (Q 301). There is no evidence
that they had chosen to overfly the Mull, and indeed the making
of the way point change suggests the contrary. Furthermore the
1000 feet a minute ROC derives entirely from the Boeing simulation
with all its deficiencies referred to above.
(d) "What is for sure is that they were
in a 1000 a minute cruise climb in that last 20 seconds before
the final four seconds of flare" (Q 304). This is far from
being sure given the deficiencies in the simulation already referred
(e) "We know they did not pull emergency
power" (Q 311). Sir John later agreed that the impact could
have destroyed any evidence of emergency power being pulled (Q
136. An example of Sir John's reliance on facts appears in
the evidence given on his first appearance before us: "The
judgment I have made about gross negligence is not based on what
I think may have happened, it is based on what I know happened
from the facts I have described to you" (Q 321). The majority
of these "facts" were the matters referred to in the
137. Sir John in his remarks had discounted the
possibility of a control jam, saying that the crew flew "a
serviceable aircraft" into the hill. On first appearing before
us he was asked about the possibility of the crew having lost
control of the aircraft due to a control jam; he explained that
if this had happened the pilots would have pulled emergency power,
which they had not done because the relevant captions had not
been activated. He therefore discounted this as a possibility
(QQ 310-11). Nevertheless he later said that he could not exclude
the possibility of a control jam having played a part in the accident
(Q 339); and his acceptance that evidence of emergency power having
been pulled could have been destroyed (see para 135(e) above)
necessarily weakens his argument against such a jam having taken
place. He emphasised however that "the crew put themselves
into a position where they were going to hit the mountain and
if any subsequent technical failure happened they had forsaken
all the margins of safety which are imposed upon our aircraft".
Although he could not exclude the possibility that some technical
event such as an engine failure caption distracted the pilots,
he considered it incomprehensible "that a minor emergency
would have so distracted them that they forgot they were about
to hit a mountain" (Q 340). Likewise Sir William Wratten
conceded that the possibility of a control jam or engine malfunction
could not be disproved (Q 1068).
138. On 11 December 2001, some weeks after our
last public hearing and when the first draft of our report had
been almost completed, we received a document from the MoD entitled
"Turning Performance of Chinook" (p 73 of HL Paper 25(ii)).
This document stated the position of the MoD and was no doubt
intended to support the views of the Air Marshals that the aircraft
was already in a position of danger at the way point change. The
document set out information about the radius of turn of which
a Chinook is capable, in an attempt to show that it was inevitable
that if the aircraft had turned at the point of way point change,
banking 30 degrees, there would have been a crash. It is unfortunate
that the Air Marshals did not provide us with this information
on either of the two occasions on which they gave evidence. The
document assumed a fairly high airspeed and did not take account
of the possibility that, if the crew had on initiating a turn
reduced speed, the radius of turn could have been greatly reduced.
The formula for calculating the radius of turn contained in the
document was helpful in demonstrating the dramatic effect of a
reduction of speed in reducing that radius.
139. On 7 January 2002 we received a further
letter from the MoD offering "key information about the speed
of ZD 576". This letter stated that at 1747 hrs the aircraft
was observed on radar to be about 7 nm on the 27° radial
from Belfast VOR. "The crash took place at 1759.30, 35 nm
down track, so the aircraft must have maintained average cruising
speed in excess of 150 knots groundspeed".
140. If this information was considered to be
of crucial importance, we fail to understand why it was not drawn
to our attention several months previously. However, we do not
consider that it is of such importance. First, while it produces
an average speed over the 35 nm, it throws no light on the actual
speed at the way point change. Second, even if the speed at the
way point change were 150 knots or more, this would not reflect
on the pilots' ability to reduce speed on making a turn to port.
Third, it adds no support to the Boeing simulation, since 150
knots groundspeed equates in the circumstances to only 125 knots
airspeed. Boeing found it impossible to match the predicted conditions
with the initial impact data as found when the airspeed at the
start of the final manoeuvre was 135 knots or below.
141. Both Sir John and Sir William gave evidence
for the second time after we had heard all the other witnesses.
Sir John explained that way point A entered in the TANS was in
fact some 280 metres south east of the lighthouse. He produced
a map (reproduced in HL Paper 25(i), p 157) showing the track
of the aircraft to the programmed way point with a mark thereon
for the point at which the aircraft would have been one kilometre
from the land. He considered that if the crew had intended to
fly VFR along the west side of the Mull they should, at the high
speed at which they were travelling, have altered course at that
point; and that they were negligent in not having done so (Q 1042).
Had they turned at the point of way point change which was only
600 metres from the cliffs they would have been in a dangerous
position. Had they turned where they thought they were when they
made the way point change, namely to the west of the actual track,
the cliffs would have been about 1 kilometre ahead (see map) and
the change would not have attracted criticism from Sir John and
Sir William (Q 1039).
142. Sir William also considered that if the
crew were visual with the Mull they should have turned left at
1 kilometre away (Q 355). He stated that if there had been a control
jam preventing an alteration of course immediately after the way
point change the pilots would have been negligent because "they
had brought upon themselves an emergency, a crisis of time"
143. Sir William summed up his position by agreeing
with the proposition that the aircraft should not have been in
either of the way point change positions (namely that in which
they actually were and that in which they thought they were) and
that any supervening circumstances affecting the flight at or
after reaching these positions were irrelevant (QQ 438-42). In
fairness to Sir William it should be explained that these answers
were simply agreements to propositions put to him, and should
be read together with his answers to QQ 335 and 1039. Both Sir
John and Sir William considered that the aircraft must have been
under control when the way point was changed and when the final
flare was initiated 4 seconds before impact.