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A New Thai Recipe

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Servicing rigs for the offshore gas industry in the Gulf of Thailand, Thai Aviation Services is in the final stages of its re-invention. A total fleet replacement with seven new Sikorskys, in two types, comes on top of an organizational evolution that replaces a partnership with independence and total local ownership. 

For many years, Thai Aviation Services (TAS) has operated in a partnership affiliation, in which partner CHC held a minority shareholding. That partnership has been dissolved under a mutually agreed plan that sees TAS now wholly Thai owned and independent of CHC. Having transitioned its heavy category operations from S61s to S92s some four years ago, Thai Aviation Services is now also replacing its six legacy S76s with a fleet of five new S76Ds. Craig Havas, Deputy Managing Director – Operations, explained the reasoning behind the decision to re-equip the fleet with the new models, “The 92s and the 76s are really two different stories.”

“The 92s were decided on approximately five years ago when we were working with a customer to amalgamate our two bases into one. Obviously the S61 is a legacy aircraft and we were finding that sourcing parts for it was becoming increasingly difficult. We needed a replacement for that aircraft, not only with increased performance but also with newer technology etc. with all those safety benefits. We decided on the S92 after considering a number of potential replacement types and the 92 virtually sells itself. Its range and payload far exceed what we could possibly use here, while its technology is superior to many of the competing types in the same weight category. It is a good fit that easily replaced the S61 and its capabilities meant we did not even have to adjust our flight schedule that much. To be honest, the S92 is almost ‘overkill’ here, as we’re not utilizing it to the full extent of its capabilities. While seat utilization percentage is in the 90s, payload utilization percentage on our operations is only in the 70s. We went ahead and got two 92s four years ago and the type has exceeded our expectations ever since then, performing extremely well. Don’t misunderstand me, it’s not that we’re really under-utilizing the S92; a large proportion of the payload oversupply is simply due to the fact that the average rig worker in Thailand is probably around half the weight of the average carried in North Sea operations. With nineteen seats filled, that’s a major weight reduction compared to a North Sea flight.”



With the S92s doing so well, TAS started to look at what they were going to do with the fleet of S76C++s. After a successful 30-year partnership, differences in visions for the future direction of the partnership led to both TAS and CHC agreeing that the shift to independence was the best direction for TAS, moving forward. Replacing the rest of the fleet was an integral part of preparing for a successful independent future and Havas elaborated, “The C++s were starting to age and we started to look for a replacement for those machines. They were all around the 10,000hr mark and we have learned from operating every S76 model from the S76A onward - starting right back in the ‘80s - that once a 76 gets to ten or eleven thousand hours, the bugs start to come out. The C++s have served us well and done a great job over the last eight or nine years but we didn’t want to put ourselves in the position of having to start carrying out major maintenance and overhaul on the whole S76 fleet. When we started looking at replacements, the leading contenders were types like the AW139 and the Airbus H175. We were somewhat impressed when we tested them but there was just something missing out of them. One factor for serious consideration was that we wanted to keep to the same OEM if possible; obviously preferring to not have a fleet consisting of products from two or more OEMs. That, in conjunction with the fact that we’ve been a dedicated Sikorsky operator for thirty years, turned the conversation towards the –D model.”

Havas admitted that, during the early stages of the selection process, the AW139 was the frontrunner and concerns were held about the 76D being late, the status of its final certification and its having a few deficits in specification and equipment. He explained though, that as time and the process continued, Sikorsky resolved those issues and made a few changes to the –D model. The result was that it gradually emerged as the frontrunner and the eventual selection to replace the legacy 76s.

A Different Partnership

In what Havas believes was an industry first, TAS worked very closely in partnership with their major customer to put out a joint tender for a fleet replacement. Both parties were fully involved in the management and evaluation of the tender and Havas outlined the ways in which the tendering partnership benefitted both operator and customer. “We were very transparent with the customer, fully revealing and explaining everything, from the way the aircraft leases work and their cost structure, how PBH is structured and even our cost base. In return we got their assistance in managing a fairly large fleet tender, negotiations with lease companies and PBH providers etc. A company the size of our customer has a lot of pull so that assistance was very valuable. Timing was also fortuitous as this was a couple of years ago when the industry was in a downturn, so lease companies and manufacturers were fully prepared to participate and negotiate.


Eight leasing companies put in tenders and we went through a three-stage evaluation process with the top four tenders. We picked the top four based on the total package, not just pricing, so we considered factors like how much support they could provide us and how much value-added component they could give us.” When the process was concluded, Milestone Aviation Group was the successful bidder and became the lessor for not only the five new 76Ds, but also the two S92s. One S92 was already on lease from Milestone so a further S92 was included in the new lease to replace the S92 previously supplied by CHC. Obvious benefits accrue from having a single aircraft OEM and a single lease provider for the entire fleet, simply due to economies of scale. These benefits include efficiency and cost of training, number and cost of parts on site and even some limited parts commonality between types. Transitioning personnel between both new types and the legacy types is also simplified and less expensive due to the similarities in designs and systems.

Advantages that the S76D offers over the outgoing 76C++ are numerous, but Havas sees the superior advanced technology as the most notable, and offering the greatest advance in safety. Because the 76Ds are brand new aircraft, they are also expected to offer greater reliability than the C++s. The new type’s Pratt & Whitney PT6 powerplants should be well supported, while Havas reports a drop in the level of support provided by Turbomeca for the engines in the older type. The –D model is much quieter than the –C, thanks in part to the new engines but also largely due to the newly designed quieter tail rotor. Havas has flown the new machine just once but has spent a lot of time in the simulator and is enthusiastic about the 76D as he normally flies the S92. “I like the aircraft,” he stated. “The technology on it is great, the automation systems, the avionics system has a lot of very cool features which I think we’re going to be able to put to very good use here in our operation. The pilots are going to love it, they like playing with new toys. The new engines are great and noticeably more powerful. Even in the limited operations we’ve done with it so far, the pilots have commented on the significant amount of additional power.

S-76D Transition

HeliOps also had the opportunity to talk to Ashley, technical training instructor for TAS. He is a licensed AME in both Canada and Australia and holds all S76 type endorsements. He is overseeing the engineering introduction of the S76D and discussed his thoughts on the new type. “I think it’s a fine aircraft and I think the new engines will prove to be robust.” He does admit to holding a personal opinion that the –D model has been a little rushed in the final design stages in order to meet certification, including the retention of some legacy features that had originally been slated for change in the new type. He also points out that the retention of those features does, however, offer the advantage of aiding in a more seamless transition to the new type, with less new material to be learned and adapted to. The largest learning for everybody,” he opined, “is that you’ve now got seven DC power buses, a new type of computer, four MFD screens - which look wonderful – and a fully integrated cockpit, which I think is great. The seats are a great improvement, the egress windows are larger; those are all improvements.”

The –D model also uses totally new main rotor blades that incorporate a composite spar, an integrated drooped tip and more sweep. Both main and tail rotor blades are also capable of anti-ice protection, although it is not foreseen that such a system will be fitted to TAS machines. Ashley believes the greatest problem that will be faced with transitioning to the new type is in sequencing. The new systems are critically demanding in the sequence in which items are switched on or off and the sequencing is often completely different to that utilized in the legacy S76s. Incorrect or rushed sequencing could result in system failures or problems and Ashley stated that Sikorsky has warned TAS that the issue is one to be very aware of when converting to the new type.

There are only two heli-decks in the Gulf of Thailand that are unavailable to the bigger S92s, due to deck size, but the 92s are able to service all the other twenty to thirty rigs in the area. The average distance offshore for the rigs is around 120nm so well within the range of the big machine and its massive payload capability means that there are opportunities to work with the customer to increase efficiency by fine-tuning the scheduling and replacing multiple S76 flights with fewer S92 flights. This fine-tuning is an on-going process as the new 76D is established into service, while TAS and the customer both closely monitor the operations. Because the customer has very tight contracts for the supply of gas to the Thai government, efficiency is very closely monitored. Havas reports that TAS is held to what he believes to be the most stringent on-time-departure regime anywhere in the world. The requirement is for an aircraft to be wheels-up no more than five minutes outside the scheduled departure time and if it is later by even one minute, Havas is required to explain why. “We track and explain our delays to the minute and there’s no-one else in the world running a KPI regime on on-time departures and aircraft availability like we are.”


The first flight of the day departs at 6:30am and operations continue until last light. Passenger flights cease at the end of daylight and the only night flights TAS carries out are medevac missions. Havas outlined the usual flight schedule, “Wednesday, Thursday and Friday are our busy days, when we’ll have eighteen to twenty flights. Saturday and Sunday that’ll drop to around twelve to fifteen flights, as will Monday as the week gets of to a slow start.”

“Flights are scheduled fifteen minutes apart, all within that 5-minute departure KPI, and we end up with three or four waves per day. By the time the aircraft are getting back it’s usually around four or five o’clock at night and most flights are approximately two hours duration, with the furthest flights to the 150km-distant northernmost platform being a three-hour return trip. We fly at ICAO standard altitude allocations with odds on the way out and evens on the way back. The 92 really likes the five to seven thousand altitude in the tropics, it gets you out of traffic so air traffic control likes it too, so we’ll be from 3,000 to 7,000ft heading out and 2,000 to 6,000ft returning.”


Apart from other TAS flights, traffic is not particularly heavy in the area. “The only other offshore helicopter traffic is mainly to the south of us but there are three flights a week to a PTT rig that operates from our field at Songkhla,” reported Havas. “Back here in Nakhon it’s a different story though, there’s a very busy commercial flight schedule into here with around twelve B737 and A320 flights in and out of here each day, plus the military traffic so it’s a very busy place. In fact, air traffic control will tell you it has one of the highest numbers of traffic movements per day of anywhere in Thailand, not including the main international airport.” Flights are monitored using the Sky Connect and Skytrac systems, with future plans including the possible standardization to just one of those systems. The S76Ds come with Sky Connect already installed while the two S92s are fitted with Skytrac, so the likely outcome would be the transition to fleet-wide Sky Connect, although Havas does admit a slight preference for the Skytrac system.

There are between two and three thousand workers on the offshore rigs in the gulf and each year TAS carries out 120,000 to 130,000 offshore personnel transfers. TAS’s full turn-key operation includes management of the facility, provision of all services including passenger check-in and baggage handling as well as the planning and management of the flights. There are about seventy pilots based at Nakhon, with a further six or seven flying from the base at U-tapao international airport. Almost all the pilots work an equal-time rotation of either three on - three off or six on - six off, with just a couple of pilots working twenty on and ten off. Forty-five engineers works equal-time rosters to maintain the TAS fleet, while around fifteen civil aviation licensed dispatchers work twenty on – ten off.

Counting all the additional administration personnel, Havas estimates a total staff on Nakhon base of about 200 people. Facilities at Nakhon include the OTC, a purpose built accommodation and training facility right on the beach that includes a restaurant, gymnasium, bar, convenience store and swimming pool. Havas explained that during the early stages of setting up the base, Nakhon was not as developed as many other provinces so the company decided to build their own accommodation and to include everything else to minimize the expense and maximize the usability of the facility.


In earlier days during the partnership with CHC, the pilot roster comprised about 98% ex-pats but TAS has been implementing a nationalization program over the last five years and is the only operator in Thailand to include an ab-initio training program. Candidates are selected from university and a small group is selected for flight training after multi-phase testing that reduces a pool of 70 – 80 suitable résumés to a group of just four or five successful program entrants. TAS has spent over 700 million baht training over 80 pilots from ab-initio level since the program began and the vast majority of them were trained at Chinook Helicopters in Canada. Havas is highly complimentary of the service provided by Chinook and explains that the selection of that company was made after looking at a large number of flight training facilities.

“We have a history of involvement with Canada, due to our long partnership with CHC, and Transport Canada has always been supportive. Considering the cross-cultural requirements of training pilots from other countries as well, Chinook was the best-placed to do it for us. Cathy, who runs Chinook, has a lot of experience in training people from other countries. The location is important too. The students get to fly in the mountains, in the snow, in icing, in hot weather, in cold weather. They get a really well rounded syllabus and a varied education in helicopter flying, which we consider to be a significant benefit.” The nationalization program extends throughout the company and is not limited to the flying personnel. Several highly experienced ex-pats are numbered among the engineering staff and they are all designated as training staff, although they work the line alongside the Thai national engineers. This is aiding the smooth implementation of the nationalization program while maintaining the highest engineering standards possible.

With a revised ownership structure, brand new fleet and a well-thought out and executed nationalization program, Thai Aviation Services is a company that has virtually re-invented itself and is undeniably positioning itself for a successful and stable future.


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