26 February 2012

Gisborne Aero Club's Airline - Eastern Airlines



By the early 1970s computers were becoming more important for the banking industry. In these pre-internet days computer data was transferred on cards and tapes by road or air couriers. In 1971 Databank Systems were using NAC to carry the computer data from all the banks in the Gisborne and East Coast area to the Hamilton and Auckland computer centres. NAC’s timetable, however, meant the bank’s full day trading could not be processed overnight.

In 1971 the Gisborne Aero Club entered into negotiations with Databank Systems about the establishment of an overnight IFR air freight service from Gisborne for the carriage of computer data. Databank initially envisaged that the service would only operate to Hamilton but, with Hamilton’s reputation for fog and a 3% non-delivery clause in the proposed contract, the Aero Club negotiated for a Gisborne-Hamilton-Auckland service.

While Databank’s proposed contract price was not sufficient to cover all the costs for the service the Club was confident that they would attract enough passengers and freight to make the operation viable.

The Club initially hoped to begin services at the beginning of August 1971, however, a licence was not issued until early November 1971. Further delays in acquiring a suitable aircraft followed. While the Club awaited the delivery of their Piper Aztec the service began in February 1972 using the Nelson Aero Club’s Piper Pa23-160 Apache ZK-CHU which operated under visual flight rules.   

In the last week of March 1972 the Gisborne Aero Club’s 1968 model Piper Pa23-250 Aztec D, ZK-DHB (c/n 27-3735), arrived in New Zealand. Over the next three weeks the aircraft was prepared for service and crew trained. The Aztec took over the service operating the IFR service on the 18th of April 1972. This commercial division of the Aero Club’s activities was operated under the Eastern Airlines banner. Databank required flights to operate Monday to Friday northbound with the return flights operated on Tuesday to Saturday mornings. In addition to the Databank services a late afternoon Sunday return service was made to Hamilton with an extension of this service flown to Auckland if there were Hamilton-Auckland or Auckland-Gisborne passengers offering.


Eastern Airlines' timetable


The Gisborne Aero Club’s operations manager and chief pilot, Mr V J Bishop, was optimistic about the future and told NZ Herald the company would put on more services if it well and that “we envisage expanding to three aircraft, possibly getting the second by the end of this year.” In addition to the regular air service the Aztec was modified to take specialised equipped with stretchers and oxygen facilities making it one of only two It is also A-category air ambulance standard aircraft in the country at the time. It was also used for general charter work.


Eastern Airlines' Piper Aztec ZK-DHB at Wellington in 1972.


Owen Jones, a Hamilton-based LAME recounts a lucky escape the Aztec had in 1972. ZK-DHB had a total electrical failure after departing Auckland in bad weather one Saturday in 1972. It was lucky to survive. The pilot could only fly on his vacuum instruments and was extremely lucky to find a hole in the cloud near Huntly that enabled him to follow the road and rail to Hamilton. He had no electrical energy available at all. The battery was depleted so no radio transmission and of course no cell-phones back then. He could not have alerted the Hamilton control tower and they would not have been able to see the aircraft until he was on the ground (no lights showing). The weather was very drizzly with only a 600 foot cloud-base. He landed and taxied to NZ Aerospace Industries.

A lot of us worked on Saturdays and I was the LAME in charge of the Electrical Section. I found both alternators to be almost completely inoperative. Upon their removal from the engines and disassembly I found that both had failed due to the stator windings having worked loose due to vibration and the windings had chafed through their insulation and were shorting to the steel stator laminations. Fortunately we had a completely overhauled replacement alternator in stock and fitted that. The best of the failed units was fitted with a new stator, bench-tested and reinstalled on the aircraft.

Meanwhile, the aircraft battery had been removed and put on charge as it was completely discharged. After a few minutes on the charger it was obvious that it was beyond salvage. Hydrometer tests showed the electrolyte was like thin brown mud. This is indicative of a battery that is "plate shedding" due to being worn out, when the active material (lead peroxide) of the positive plates drops out of the grid lattice and falls to the bottom of the battery case (and goes into suspension in the electrolyte). A new fully-charged battery was installed.

Ground-running showed the electrical system to be fully functional again but the pilot insisted I go with him on a test-flight to check it all out in the air. He was so un-nerved by his experience earlier in the day.

The weather was still crap and still only a 600 foot cloud-base but he managed to get the tower to approve a special VFR test-flight and they directed the aircraft to do the test flying to the south-east of Hamilton airfield toward Cambridge. While the pilot stooged around just under the cloud, I operated all the electrical system switches and ensured each alternator was performing OK. We retuned to the workshop and I wrote up the log entries for the work done.
This emergency really was a close-call for the pilot and hopefully there will be an incident report filed somewhere about it and corresponding entries in the log books (whoever has them now).

The most important thing to learn from this was that the aircraft battery was in such a poor state that it likely had only about 10% capacity to hold charge. That means that when the alternators went dead the battery would have only lasted a few seconds or maybe just minutes. A battery in good condition (that means, for aircraft, having at least 75% capacity) would have enabled the pilot to load-shed non-essential services and make a radio call and get to Hamilton with sufficient electrical energy. Of course we don't know how long it was before the pilot detected the alternator failures, but regardless that battery which was in the aircraft should not have been in such a poor state.

The initial outlay of $45,000 for the Piper Aztec was a huge investment for the Aero Club. On top of this Eastern Airlines was also required to charge 10% more than NAC which also flew the same route and this made the service less attractive for passengers. Unfortunately for the Aero Club passenger loadings and additional freight levels were not adequate to meet the shortfall between the Databank contract price and the operating costs. 

Soon the Club was in serious financial difficulties and this ultimately led to the appointment of a liquidator who wound up the club and Eastern Airlines. The final service was flown Gisborne-Auckland-Ardmore-Gisborne on the 20th of October 1972 followed by a 15 minute "Goodbye Gisborne" low level flight later that day. 

4 comments:

  1. From my logbook last commercial flight ZK DHB was GS-AA-AR-GS 2.5 hrs 20 Oct 1972 followed by a 15 min "Goodbye Gisborne" low level flight later that day. (ATCO K Keepa had to go down for a call of nature at that time)

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  2. Thanks for that... the post has been updated.

    ReplyDelete
  3. ZK-DHB had a total electrical failure after departing Auckland in bad weather one Saturday in 1972. It was lucky to survive. The pilot could only fly on his vacuum instruments and was extremely lucky to find a hole in the cloud near Huntly that enabled him to follow the road and rail to Hamilton. He had no electrical energy available at all. The battery was depleted so no radio transmission and of course no cell-phones back then. He could not have alerted the Hamilton control tower and they would not have been able to see the aircraft until he was on the ground (no lights showing). The weather was very drizzly with only a 600 foot cloud-base. He landed and taxied to NZ Aerospace Industries.
    A lot of us worked on Saturdays and I was the LAME in charge of the Electrical Section. I found both alternators to be almost completely inoperative. Upon their removal from the engines and disassembly I found that both had failed due to the stator windings having worked loose due to vibration and the windings had chafed through their insulation and were shorting to the steel stator laminations. Fortunately we had a completely overhauled replacement alternator in stock and fitted that. The best of the failed units was fitted with a new stator, bench-tested and reinstalled on the aircraft.
    Meanwhile, the aircraft battery had been removed and put on charge as it was completely discharged. After a few minutes on the charger it was obvious that it was beyond salvage. Hydrometer tests showed the electrolyte was like thin brown mud. This is indicative of a battery that is "plate shedding" due to being worn out, when the active material (lead peroxide) of the positive plates drops out of the grid lattice and falls to the bottom of the battery case (and goes into suspension in the electrolyte). A new fully-charged battery was installed.
    Ground-running showed the electrical system to be fully functional again but the pilot insisted I go with him on a test-flight to check it all out in the air. He was so un-nerved by his experience earlier in the day.
    The weather was still crap and still only a 600 foot cloud-base but he managed to get the tower to approve a special VFR test-flight and they directed the aircraft to do the test flying to the south-east of Hamilton airfield toward Cambridge. While the pilot stooged around just under the cloud, I operated all the electrical system switches and ensured each alternator was performing OK. We retuned to the workshop and I wrote up the log entries for the work done.
    This emergency really was a close-call for the pilot and hopefully there will be an incident report filed somewhere about it and corresponding entries in the log books (whoever has them now).
    The most important thing to learn from this was that the aircraft battery was in such a poor state that it likely had only about 10% capacity to hold charge.
    That means that when the alternators went dead the battery would have only lasted a few seconds or maybe just minutes. A battery in good condition (that means, for aircraft, having at least 75% capacity) would have enabled the pilot to load-shed non-essential services and make a radio call and get to Hamilton with sufficient electrical energy. Of course we don't know how long it was before the pilot detected the alternator failures, but regardless that battery which was in the aircraft should not have been in such a poor state.
    Owen Jones LAME 10506

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    Replies
    1. Thanks Owen... A great piece of history and a lucky day for the PIC. The post has been updated accordingly. Just for the record, DHB ended its days with Air Adventures from Christchurch. It was broken up in 2002 with the parts going to Sunair.

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