5. Hypotheses
about the Cause and Location of the Accident
5.1
Reflections on the
flight of the ”Latham”
During the open hearing in
Tromsø on 30 September, project developer and seaplane pilot
Morten Waltinsen submitted some interesting ideas about the
“Latham 47” aircraft and its characteristics as a seaplane. We
will not go into detail regarding Waltinsen’s report, but
rather look more closely at aspects of the aircraft, the crew,
the weather conditions and the circumstances surrounding the
operation itself, that may have had some significance for the
fate of the flight. Technical data about the type of aircraft
and assessments made by Hovdenak/Hoel and Riiser-Larsen have
been included in this conclusion with regard to the flight
itself
The Crew
The crew members
were
French and were led by
Captain René Guilbaud,
born 1890, an experienced
pilot from the French Naval
Air Force who served his
country in World War I. The
co-pilot was Albert de
Cuverville, born 1892. The
aerotechnicians were maitre
Gilbert Georges Paul Brazy,
born 1902, and 2nd maitre
Emile Valette. The French
crew must be considered
well-qualified for the task,
even though they lacked
experience of Arctic operations.
The lack of Arctic experience was compensated by the
participation of initiator and Arctic explorer Roald Amundsen
and navy pilot Leif Ragnar Dietrichson. The Norwegian
contribution to this operation consisted largely of planning
and preparation. It is only natural to assume that neither of
the Norwegians took a direct part in the actual manoeuvring of
the aircraft.
The “Latham” took off from Normandy, France, at 9.05 a.m. on
June 16 and flew non-stop to Bergen where it landed at 9.45
p.m. Next day, after a stopover of about 22 hours, the
aircraft took off from Bergen at 8.20 p.m. landing in Tromsø
at 6 a.m. on June 18. After a stop of just under 10 hours in
Tromsø, they took off again at 3.55 p.m. and were last seen
for certain heading in a northerly direction north of
Hekkingen lighthouse.
One can only assume that the crew set off on this trip with
expectations, a feeling of excitement and a certain fear of
the unknown. There had been little time for planning and
preparations. We do not know how many hours the crew had
allowed for rest and sleep in Bergen, but due to lack of both
time and support crew, it is obvious that the crew would have
had to carry out most of the essential tasks themselves,
including loading, research, planning, etc. The flights from
Bergen to Tromsø, and then from Tromsø, took place at night.
The crew had not had time to acclimatize themselves to
conditions such as the midnight sun and 24-hour daylight. The
stop in Tromsø from 6 a.m. until departure at 3.55 p.m. took
place in an animated and stressing atmosphere where there
would hardly have been ant time for rest. In all probability
the crew would not have been fully rested on their departure
from Tromsø and are likely to have lost track of the time of
day since their last trip to Tromsø took place at night time.
The midnight sun and bright nights would most likely also have
been a distracting factor.
The “Latham
47” Prototype II
The French
aviation industry was among the best in the world, and at the
time the Latham was a well-equipped and modern aeroplane with
most of the advanced instrumentation that was available. It
was primarily constructed for long-distance flights and was
taken out of service on the preparations for trans-atlantic
flights in order to search for the “Italia.” Plywood was used
to reduce the weight of the aircraft itself, and to increase
its payload capacity. For the same reason, a boat-shaped
fuselage was chosen in order to avoid the increased weight and
air resistance that two sturdy pontoons would represent. The
compromise involved two small pontoons, one at each wing tip,
designed to balance the aircraft on the water. However, during
operations on the sea, when there are strong winds and
considerable swell, a construction with a keel and two wing
pontoons causes great strain on the wings, wing pontoons and
wing fittings, particularly when the direction of the wind
does not correspond to that of the waves. Under such
conditions, the aircraft was probably difficult to manoeuvre
on the water.
The range of the aircraft was more than sufficient for the
planned distances with intermediate landings and refuelling.
The aircraft was equiped with instruments for blind flying,
i.e. it could fly through areas of cloud or fog without the
need for references to the ground or sea surface. However,
flying with visual references to the ground/sea surface was
the norm at that time. The instruments of the time were
rudimentary and not the easiest to manouevre an aircraft by.
Furthermore, in time they could accumulate errors and needed
to be reset on a regular basis, something which normally
required visual reference to the ground. Some of the
instruments were retrospective, thus indicating change of
course, loss of altitude and so forth, after a certain period
of time had elapsed. In actual fact, the length of time the
instruments could be used when flying through cloud was
limited by the need to reset.
Weather conditions and daylight
The weather in the Tromsø area on 18 June 1928, was dominated
by low pressure over central Scandinavia. North Norway was
under the influence of a high pressure zone east of Svalbard
that crossed over to the Kola peninsula. The result north of
Tromsø was a north-easterly wind with fog and fog banks. The
wind increased in strength further north. In the area around
Bjørnøya there was a north-easterly wind and the fog had
lifted and given way to hazy weather with low stratus. If we
assume that the aircraft held a steady course for Bjørnøya
after passing Hekkingen lighthouse, the crew would have had
the midnight sun 60-70 degrees to the left of the nose of the
aircraft. Low sunshine from that angle combined with fog and
mist would have made visual flying conditions difficult. The
horizon becomes diffuse and indistinct. It becomes difficult
to find one’s bearings and to distinguish where the sky ends
and the sea begins, or vice versa. The references necessary
for visual flying are erased. The prevailing flying conditions
were instrumental to disorientation and a false sense of the
aircraft’s horizontal plane.
The radio message
If
we assume that the “Latham” flew straight from Hekkingen
lighthouse towards Bjørnøya after passing Hekkingen at 4.20
p.m. local time, the aircraft’s position would have been
approx. 72°
30’ N, 018°
E when the radio call was made between 6.45 and 6.55 p.m. The
radio message mentioned nothing about technical difficulties
and indirectly confirms that the flight was progressing
normally and as planned. The transmission revealed
difficulties with the radio connection, but this is normal and
a well-known phenomenon in Arctic regions during the summer,
due to varying atmospheric conditions. It is correct to assume
that the flight went more or less as planned until 7 p.m.
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