Andrew Doyle/LONDON
Technology WHICH allows ageing airliners to meet the latest noise regulations coming into force in Europe and the USA is big business. It is an industry attracting a growing number of participants offering diverse solutions. The result is that operators must decide how to balance the capital costs of the modifications against the performance enhancements offered, and the resultant effects on the residual value of the aircraft.
Re-engineing is once again being talked about as a viable solution in the civil sector, while hushkit sales continue apace, especially in the USA. One manufacturer, Raisbeck Engineering, has even managed to gain US Federal Aviation Administration certification for a Stage 3-compliant Boeing 727 modification which does not involve re-engineing or hushkitting.
The widening gap between the requirements of airlines operating within Europe and the USA has been highlighted in the past year. Non-Stage 3 (USA)/Chapter 3 (Europe) aircraft will be banned from operations from 1 April, 2002, and 31 December, 1999, respectively. The majority of European carriers with large non-Chapter 2-compliant fleets are ordering new aircraft to replace them - and buying hushkits only to boost the resale value of the aircraft. The problem is that many European airports have unilaterally introduced even stricter regulations which cannot be met by hushkitted aircraft. In the USA, the major carriers are able to hushkit large fleets of aircraft and operate them throughout the country without penalty.
Programme launches
The planned launch of two re-engineing programmes - Omega Air's for the Boeing 707 and Fokker Aviation's for the F28 - is perhaps surprising in view of the limited success that previous airliner re-engineing programmes have enjoyed. In the case of the 707, only military customers have so far had the financial resources required to commit to large-scale re-engineing programmes.
There is no doubt, however, that the complex economics associated with re-engineing can make sense in certain niche markets, as was highlighted by the successful Cammacorp McDonnell Douglas (MDC) DC-8 re-engineing project in the 1980s, and the more recent UPS 727-100 re-engineing programme, involving the CFM International CFM56 and Rolls-Royce Tay, respectively. A comparison of the current 707 hushkitting and re-engineing programmes provides a good illustration of the cost and performance trade-offs involved.
Burbank Aeronautical II (BAC II) is developing a hushkit for the 707's Pratt & Whitney JT3D engine, which the company claims will bring the aircraft inside Stage 3 limits, reduce fuel consumption by 11% compared with Stage 2 hushkits, and cost around $3.5 million per aircraft. "It's a re-engineing in a hushkit's clothing - there are no fuel-burn penalties, no flight restrictions and no acoustic trades," claims Thomas McGuire, vice-president - marketing at BAC II.
Omega Air claims that its programme to re-engine the 707 with more powerful P&W JT8D-219s will also bring the aircraft comfortably within Stage 3 limits, while reducing fuel consumption by 20% and aircraft weight by 180kg, yielding a range increase of 30%, and a 45% reduction in time to initial cruise height. The aircraft will "-outperform the [Airbus] A310-300 in nearly all parameters as an aerial-refuelling aircraft", Omega claims.
Using four brand-new JT8Ds, which remain in production for the MDC MD-80, pushes the cost per aircraft up to $15 million. Omega is developing the re-engineing programme for application to its own portfolio of some 25 707s, and aims to gain certification by April 1999.
The BAC II hushkit, meanwhile, was flown for the first time on 7 April, fitted to a JT3D-7, and full-scale noise tests using a 707 with all four engines modified will begin in July, and take around three weeks to complete, says McGuire. Further tests on an aircraft fitted with the less-powerful -3B version of the engine will follow. "If you can make your noise test on the -7 you can make it on the -3B," McGuire says.
McGuire also claims that BAC II's hushkit will not be caught out by the European Union's refusal to sanction so-called "acoustic trades", a practice which is allowed in the USA. The issue of acoustic trades illustrates how equivalent noise limits are being implemented more stringently in Europe than in the USA.
For noise-certification purposes, take-off, sideline and approach measurements are made. In the USA, exceeding the limit in one of the three categories is permitted, provided that the aircraft is comfortably inside the limit in one of the other two categories. Europe demands that the limit is met in all three categories. "Trades are fine for the FAA, but Europe is basically saying: 'Forget trades'," says McGuire.
BAC II is expecting to gain a US supplemental type certificate (STC) for its JT3D kit around October, and will begin deliveries to customers "almost immediately" afterwards. From January 1998, the company will be manufacturing three shipsets a month, says McGuire. BAC II has spent some $20 million over the past three years developing the 707 kit.
Potential sales
Although no orders for the kit have yet been announced, McGuire says that the potential market consists of 150 707-300s, with most of that total being operated as freighters, alongside 12 corporate aircraft.
"There are only about ten to 15 non-military 707-300s in the USA, and the rest are in Africa, Latin America, the Middle East and Europe," says McGuire. BAC II is also developing a Stage 3 hushkit for the DC-8-50 and -61, which should receive an STC in July 1998. The DC-8 kit is applicable to around 100 aircraft still in operation, says McGuire.
The cheapest way of achieving Stage 3/Chapter 3 compliance for a 727-200, meanwhile, is the Raisbeck Engineering modification, priced at $695,000. The package involves slightly reducing the maximum thrust of the existing engines, "overspeeding" the take-off flap settings and limiting maximum take-off weight to 75,820kg. A consequence is that the take-off run is extended by around 140m (460ft), and approach speeds are higher as maximum flap for landing is reduced to 25í.
Federal Express Aviation Services, meanwhile, has been selling JT8D hushkits for the 727 for several years and, in April, began offering a Stage 3 kit for the 89.6t maximum-take-off weight version of the aircraft. The company now claims that it offers kits for "-any 727 in the world at design take-off thrust".
Hushkitting the 727 is significantly more expensive than the Raisbeck Engineering solution, with prices ranging from $1.9 million for the 727-100, to $2.9 million for the heaviest version of the -200. With hushkits, however, the aircraft are not subject to operating restrictions and will probably retain a higher residual value.
Phil Blum, manager of marketing at FedEx Aviation Services, does not consider re-engineing to be a major threat to the hushkit market. He says: "Re-engineing is really a different market to hushkitting. It is typically a niche product for operators looking for extra range and improved field performance. Hushkitting is a low-cost solution for meeting Stage 3/Chapter 3."
Re-engineing works for "specific missions", he adds, where the performance improvement can be translated into increased revenue to cover the higher capital cost of the aircraft.
One 727 re-engineing programme is now under way, headed by California-based Rohr, and supported by P&W. The "Super 27" package involves replacing the aircraft's outboard engines with the latest, -200 version of the JT8D, and adding a new acoustic exhaust mixer to the existing centre engine. The company acquired the rights to the STC once held by Valsan, which had converted 23 aircraft.
The modification, which costs $12-15 million, brings the aircraft inside Stage 3 limits and provides a 6-7% reduction in fuel consumption, Rohr claims. The company also says that more than $2.5 million of the cost can be recouped from the sale of the engines which are removed.
Market potential
The US company predicts a market for the conversion of 50-100 aircraft, from the more than 1,300 still in operation. The most likely customers are package-freight, charter and corporate operators.
BMW Rolls-Royce has become the latest manufacturer to outline proposals for a 727 re-engineing programme, based around the Anglo-German company's BR715 turbofan. The project is being studied in conjunction with Dee Howard of the USA. The modification would involve installing BR715s in the number one and three (outboard) positions, and either a smaller BR710, R-R Tay or derated JT8D in the centre position.
Richard Smallwood, BMW R-R executive vice-president, business, admits that the expensive modification could appeal to customers with "a fairly unique operation".
Smallwood believes that orders could come from package-freight carriers with an eye to being "good neighbours", which want to operate quieter-than-hushkitted 727s because most of their operations are carried out at night. He adds that the programme would be most likely to be launched by a fairly large operator in the USA, with possible follow-on orders from smaller carriers in Europe.
"We are very realistic about whether we can get the thing to really make sense," says Smallwood. "There has to be sufficient critical mass to make it work - a big enough order." He adds that the size of the launch order required is into "-good double digits-50-plus aircraft to get the numbers to work".
BMW R-R is targeting a potential market of 70-150 aircraft, the majority of which are operating in the USA, and is working towards an entry-into-service date of mid-2000. Such a re-engineing programme could cost $10-15 million per aircraft.
The BR715 is around 10% more fuel-efficient than the R-R Tay used for the now-completed UPS 727-100QF re-engineing programme, Smallwood claims, adding that the company believes that the most cost-effective solution for the centre engine would be the use of a derated JT8D. This would avoid the need for an enlarged "S" duct, as used on the 727-100QF, to accommodate the larger-diameter Tay or BR710 engines.
An airframe which has attracted a proposed re-engineing programme for the first time is the Fokker F28. Fokker Aviation , leading the project, has selected R-R Tay 620 engines to replace two R-R Speys. The Tay engine was used on Fokker 70 and Fokker 100 types.
The F28 is seen as promising for re-engineing because further hushkitting the aircraft to meet Stage 3/Chapter 3 would invoke severe performance penalties. Large F28 operator Horizon Air is a front-runner to launch the programme.
Extended range
For $8.5-9.5 million, customers for the conversion would get 15-20% more range, because of a 12-20% reduction in fuel consumption. In addition, a 1.14m-long fuselage plug would be inserted forward of the wing to offset the weight of the larger engines, providing room for an extra row of passenger seats.
It is not just first- and second-generation narrowbody airliners powered by low-bypass-ratio engines which are falling foul of the new rules. The partnerships of Air Foyle/Antonov and Heavylift/Volga-Dnepr must hushkit their Antonov An-124 freighters to allow continued operations in Europe and the USA, despite the fact that they are fitted with "big-fan" engines.
The decision to develop a hushkit followed a study into re-engineing the aircraft with the General Electric CF6-80C2, which was deemed to be not economically viable.
The Progress Design Bureau, which designed the D-18T turbofan, and Antonov, have developed a Stage 3 hushkit which involves "-drilling a very large number of microscopic holes in part of the nacelle", says Paul Furlonger, Air Foyle commercial manager.
Rules covering the progressive phase out of Stage 2 aircraft were starting to affect operations in the USA, Furlonger adds. "We were allowed three [operating in the USA] during 1995 at any one time, which went down to two in 1996, and is now back up to three," he says.
This is because the first aircraft to be fitted with the hushkits was recently put back into service. All of Air Foyle's fleet will be modified as more kits become available, says Furlonger.
Source: Flight International
