This Site is dedicated to all those families of the people that have tragically disappeared on flights in and around New Zealand. I only hope that from all the effort in building this site and from all the effort of those taking part in this venture, that it will bear fruit in bringing ‘closure’ to their memories!
Gavin Grimmer
Gavin Grimmer
This annoyed me for a while until I realised that there was another possibility:...
Ronald Hunter said Father Crosbie commented that the plane was using more fuel than usual.
This would mean that they would have taken off with a fuel endurance of 1.36 hours (1 hour 9 minutes) at the higher usage rate of 72 litres/hr (calculated page 15 ).... maybe less endurance... if the problem causing the high burn rate got worse! - i.e: a fuel leak
At a maintenance organisation a few weeks prior, the aircraft owner complained that the motor was prone to run roughly (over rich?) at the top of the climb but settled down after a minute or two. Generally, leaning out the fuel mixture with the mixture control can cure this. He was also "not happy" about the Exhaust Gas Temperature Gauge (EGT), although the report does not say why. - Maybe it was showing a low temperature reading (over rich)?
I’m not trying to draw any conclusions from these complaints – only that both of these complaints could indicate that there possibly was a problem?
I found the following Airworthiness Directive (AD) on the Internet, which could very well explain the fuel loss, especially as they were flying in icing conditions that day (freezing level 800ft). Remember this Cessna 180 was built in 1953. (I have highlighted some of the words):
Ronald Hunter said Father Crosbie commented that the plane was using more fuel than usual.
This would mean that they would have taken off with a fuel endurance of 1.36 hours (1 hour 9 minutes) at the higher usage rate of 72 litres/hr (calculated page 15 ).... maybe less endurance... if the problem causing the high burn rate got worse! - i.e: a fuel leak
At a maintenance organisation a few weeks prior, the aircraft owner complained that the motor was prone to run roughly (over rich?) at the top of the climb but settled down after a minute or two. Generally, leaning out the fuel mixture with the mixture control can cure this. He was also "not happy" about the Exhaust Gas Temperature Gauge (EGT), although the report does not say why. - Maybe it was showing a low temperature reading (over rich)?
I’m not trying to draw any conclusions from these complaints – only that both of these complaints could indicate that there possibly was a problem?
I found the following Airworthiness Directive (AD) on the Internet, which could very well explain the fuel loss, especially as they were flying in icing conditions that day (freezing level 800ft). Remember this Cessna 180 was built in 1953. (I have highlighted some of the words):
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Part 1 - Airworthiness Articles
Part 1 - Airworthiness Articles
AAC 1-58 Early Series Cessna 180 Fuel Tank Vent System 13/90
The FAA have issued AD 90-21-08 addressing C180 fuel vent system icing.
The FAA AD addresses reports over the years of fuel loss induced by siphoning out of the alternative vent tube due to ice accretion (blockage) in the primary over the wing vent tube (above the cabin). The fuel loss can be hidden from the pilot as the fuel gauges may give erroneous fuel readings as the fuel bladder may be lifted towards the top of the wing due to the negative tank internal pressure.
The AD affects 2488 Model 180 Series airplanes manufactured between 1953 and through 1955 with the over the wing fuel tank vent tube systems, with approximately 1000 airplanes still operating world-wide.
The FAA AD requires within the next 100 hours of service installation of a placard warning pilots of erroneous fuel readings and subsequently the installation of a new fuel bladder with the primary vent tube being relocated to under the wing.
In Australia there are 14 aeroplanes which are affected by this AD. The Major Defect reporting system indicates that the Australian fleet has not reported any similar problems in service. Considering this information along with, the cost associated with this FAA AD, the aircraft having been in service for 35 years and that the ice accertion in the primary vent tube is most likely caused by flying in icing conditions, this Authority does not consider it mandatory for the Australian fleet to comply with the FAA AD.
However, if an operator wishes to install the modification, their nearest Field Office or Maintenance Organisation can advise of the relevant Cessna data detailing procedures required to incorporate a modified vent system.
This 1972 photo of ZK-BMP clearly shows the Fuel tank vent above the windscreen on the cabin
