By Bjorn Fehrm
04 Aug 2015, © Leeham Co.: Boeing has for the last 20 years used an internal set of rules called Integrated Airplane Configuration ruleset, or IAC for short, for how it describes its own and competitors’ aircraft. These configuration rules, while comprehensive and consistently applied, have some problems, the most obvious is that they are 20 years old.
The IAC rules have filled an important role for Boeing: they have been the yard-stick how its different aircraft stack up but also how to value competitor’s aircraft. All aircraft in Boeing Commercial Airplanes (BCA) have been configured and scrutinized with IAC.
The world of civil airliners have moved on since the creation of IAC in the early 1990s and there was time for an overhaul. This has now been done, after several years of internal work the new configuration rules are ready for prime time under the name of “Boeing Standard Rules”.
The most externally visual effect is that officially published seat information and performance data for Boeing’s aircraft change. The configuration ruleset dictates how everything is measured against a standardized set of parameters for each aircraft type and use.
We talked with Boeing’s Director for Product Marketing, Jim Haas, how to decipher the changes and how aircraft stack up before and after being “Standardized”.
The need for a configuration ruleset
A new civil airliner can be configured with nearly unlimited flexibility in terms of cabin seat types, aisle width, space for common areas, lavatories placement and facilities for serving the passengers like Galleys, CART storage, Closets for coats and Stowage. Its data can also be given with a bare minimum crew and fuel reserves or with a more airline like setup.
When comparing aircraft in marketing information or during competitive procurements the costs of the aircraft is represented as “per seat-mile”. A configuration that can pack more seats into an aircraft will generate lower “per seat-mile costs”. The lower the per seat-mile costs, the more competitive an aircraft becomes. Also the aircraft which is measured with the leanest crew and smallest fuel reserves will win. How the “picking and packing” gets done and what is allowed is governed by the configuration ruleset.
Boeing’s historical ruleset
Around 1990 Boeing realized that it did not have a consistent and standardized ruleset for how it configured its different aircraft. Marketing materials and information to customers over aircraft were unique; comparisons were difficult because the different aircraft’s capabilities were not conceived with a common yard-stick. Each new aircraft type could mean a new cabin configuration or new type of mission rules which could not be compared to the configuration for an earlier type. Boeing realized something had to be done.
It was decided there should only be one comprehensive set of rules that should be applied to all aircraft, new or old. It was called “Integrated Airplane Configuration ruleset”, IAC. IAC should apply to all aircraft and for internal information as well as material that was given to public or customers. IAC should also be used for competitor aircraft comparisons. Boeing’s cabin department conceived IAC compliant cabins for each competitor aircraft for the purpose and their performance department modeled the aircraft with IAC reserves and crew requirements.
Customers might in addition ask for cabins made with their own specific rules and evaluations using their specific operational rules but the base information around the aircraft would be using IAC.
IAC had rulesets for Short Range (SR), Short-to-Midrange (SM), Midrange-to- Long range (ML) and Long Range (LR). For most rulesets, there were one, two and three class cabins, dictating the crewing, mix of seats and amenities.
The ruleset stipulated:
The combined surface space needed in an aircraft to seat and serve a first class passenger can be three to four times the space for an economy passenger. For business it is around two times. It is then clear that it is important not only how many seats an aircraft configuration has but how many first and business class versus economy. An aircraft with a large economy class would win a sales campaign based on “low cost per seat-mile.”
At the same time a small premium sections means the passenger revenues per seat, the yield, would be low. The need for a good ruleset to arbitrate all this is clear.
While the IAC was very comprehensive for all these factors, it did not regulate the ratios of premium to coach seats in the aircraft. It might have had such rules but then they were not obeyed. There were numerous examples of a 737-800 with, e.g., 12 premium seats and 150 coach being compared to a 737-900 with 12 premium seats and 168 coach. The same happened for twin aisle aircraft. It is evident that the comparison of the per seat-mile costs between these aircraft makes little sense.
Boeing was not alone not attacking this problem. The same problem exists with other OEMs. Haas, Boeing’s Director for product marketing, confirmed that the “Standard Ruleset” fixes this problem; the ratios between classes are kept constant for different size aircraft.
It shall be mentioned that Leeham Co. and LNC observed the problem for years and to enable apples-to-apples cost comparisons between aircraft we created and applied a Normalized ruleset which includes a fixed ratio between premium and coach classes for each aircraft we analyzed.
The need for new standards
Haas explained that as IAC got on in years, its standard for seats and their capabilities grew old as well. It was difficult to change however; every change meant that all existing information was rendered useless and, as said, everything was in IAC: internal, customer and competitor information.
Boeing used a patch to prolong the life of IAC. By using its three class rules when others used two class, the total seat counts were close. For any more serious purpose, specialized cabins were made to enable apples-to-apples discussions.
As an example, Haas took the 787-8 that has 242 seats in IAC three class and an identical 242 seats in Standard Rules two class. But the problems became apparent when analysts or interested public started to dig deeper. While Airbus was showing its business class as lie-flat with 60 inch pitch, IAC mandated recliners at 39 inch pitch. It gave the impression of wanting to compromise on customer comfort to show better seat numbers.
For anyone digging deeper, they would find the Boeing IAC rules most of the time being more strict on things like crew staffing and their rest areas, mission reserves, catering, lavatories, stowage or rules around the economy class. But the damage was done.
Boeing’s “Standard Rules”
Over the last several years, work has been invested to update the Boeing ruleset to something closer to what today’s airlines use. Haas would not go into details on the new rules as Boeing has not briefed all its customers on the news and Boeing doesn’t want them to read the details in the press first.
As we have worked with IAC in detail when creating our Normalized ruleset, we can see where Standard makes changes and why. Standard e.g. focuses on modern two class cabins where business has lie flat seats with direct aisle access. First class is only applied to large aircraft, see Figure 1.
The new Standard ruleset is close to our Normalized ruleset; our reserves and crewing policy is to our knowledge the same and our seating is within 2%-3% of Boeing’s new Standard seating.
Example: we have 238 seats for 787-8 vs 242, 292 seats for 787-9 vs 290 and 331 vs 330 for 787-10. The seat ranges for 777-8X and -9X represent that these have not yet reached design freeze, according to Boeing. Our seating is in the range at 360 and 410 respectively. For 747-8i we have used 405 three class as our Normalized seat count; Boeing now uses 410 vs 467 under IAC.
The changes in an aircraft’s design range for Standard vs. IAC are significant. We have used our performance model to check the differences. The majority of these changes can be explained with an increase of the payload weight. Haas explained that it is more checked bags that makes today’s “Pax+bags” go beyond IAC’s 210 lb for Long range rules and 200 for Short range (our weight data). The increase for Standard over IAC “is around 15 lbs,” says Haas. This is an increase of the payload fraction of 7% and accounts for around two thirds of the range changes.
The last third is because of heavier seating. A modern lie-flat business seat weigh about two times the ones used in IAC. For certain aircraft, the range change is small for others large. The 737-700/MAX 7 versus 737-800/MAX 8 and 737-900/MAX 9 are good examples. The later aircraft are fuel limited at their design range. As explained in my Corner two weeks ago, this brings a different trade: “increased empty weight and payload” for “fuel weight.” The result is a smaller range drop than for models which are weight limited at their design range (-700/MAX 7).
Haas assured that the change of ruleset has not been used to cover any “as-yet covered” range deficits; having done our checks we see no need to doubt that.
We appreciate OEMs that use structure and consistency to bring clear and concise information. Boeing is in several areas a leader with as examples good OEW and payload/range information in its Airport planning guides. Both need to be based off a good ruleset to bring relevant information.
IAC was conceived to bring structure and clarity to an area that still today lacks standardization and transparency. As it grew old, it started to work against its purpose. With Standard Rules, this seems to have been fixed in a good way.