Boeing start applying “Standard Rules” to its and competitors’ aircraft.

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:

  • Applicability in terms of aircraft and mission type (single/dual aisle, domestic/international) and reserves to be used for the missions.
  • For cabins the number of classes, their staffing with crew and their detailed data:
    • Seat type, width, pitch, recline with dimensions, weights.
    • IFE type used and its weights.
    • Aisle widths and areas for boarding and deplaning
    • Number of Lavatories per class and seats
    • Number of CARTs per passenger and class
    • Closet and stowage areas per passenger and class

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.

IAC vs Standard2

Figure 1. Boeing aircraft seating and range with IAC vs. Standard Rules. Source: Boeing.

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.

Range change

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.

40 Comments on “Boeing start applying “Standard Rules” to its and competitors’ aircraft.

  1. A few questions.

    1) How do the other OEMs compare at the moment on accuracy versus the new Boeing Standard Rules?
    2) Will the BSR be easier to update/evolve than the IAC?
    3) Why does the industry not have an ICAO (or similar) mandated ‘independent’ standard?

    • Hi Woody,

      1. I don’t think you mean accuracy but comprehensive and airline like rules. We don’t have all the details of Standard but as we understand it its the most Airline like ruleset in the industry. Bombardier use the same Pax+Bags weights (really mass 🙂 ) after LH ask them to use 225lb. Others use the FAA/EASA minimum of 95kg or 208/210lb.

      2. We don’t know, it is very all encompassing if as thorough as IAC. But it seems Boeing took a large jump (the 225lb indicates that) so it should be relevant for quite some time.

      3. FAA/EASA/JAR has minimum standards and ICAO has recommendations. Boeing goes beyond that.

  2. There was a time, not long ago, when there was no electricity standard in Europe. So it was quite chaotic, for each country had its own standard. Today there is only one standard in the EU and it is the highest because it has been based on the German electricity standard. Same for measurements. Most of the planet, except the US, has adopted the metric system which is the most convenient. It has been used by scientists for a very long time now, even in the US. For the same obvious reason everyone should have the same standard for commercial aviation metrics. If Boeing now has the highest standard it should be adopted by all parties, with perhaps some adjustments that would satisfy everyone involved. IATA should put in place this new standard and enforce it among its members. IATA represents the aircraft customers and they are the ones who should tell the manufacturers what standard to adopt so that they can make meaningful comparisons. For the automobile industry there are government standards that make sure all manufacturers use the same standard for fuel consumption for example. In commercial aviation the governments relie on ICAO and IATA to establish those standards. ICAO should raise its standard to the level of Boeing or let IATA take care of it.

    • I think the Airlines can figure it out for themselves. I don’t see this as an areas for standards as mandated.

      I do work with the metric electrical stuff and in the application of relays find it appalling. A US NEMA contactor is vastly superior because its actually rated and tested to handle standard conditions, not ideal ones. Same thing that got us ISO 9000. Ungh.

  3. What are the fuel loads of the Max8 and Max7 at this “standard” payload and range? Since obviously, the Max 8 has more fuel loaded. What are the ranges and payload of the Max7 and Max8 if the tanks are fully filled?

    • It seems that with the MAX 7’s 500nm range reduction and the CS300 350nm performance gains, that the CS300 has an equal range but better fuel consumption due to its more efficient wing and being 12,000lbs lighter.

        • Bjorn, do we have the OEW and MTOW of the production CS100/CS300 yet? I wonder how physically different the production aircraft will be from the FTVs. Even if the performances are better than expected I assume they would still try to make them better still if they can. Especially in view of the fact that the empty weight is slightly higher than they wanted.

          • Hi Normand,

            we’ve had good conversations with BBD on the CS100/300 and we have a good handle on the weights. Overall the situation is good, I only pointed out to Trooper that the actual better performance in total aircraft fuel burn per nm is in the 1% range as also publicly declared by Rob Dewar. This is nice so, but does not explain the range increases. These come from adjustments of weights which has been possible without losing field performance compared to what was promised. Overall the changes needed for production CS100/300 compared to prototypes seems small if not minimal.

            What has taken all the time is the avionics/FBW/systems integration. No wonder, it is a huge amount of functionality that shall be merged into a safe whole.

          • Thanks Bjorn. Your reply reassures me. But I just want to make sure I understand this.

            1. The aircraft has better range because it can take more fuel than they thought they could, correct? 2. And when Rob Dewar said that they had fuel volume to spare that is what he probably had in mind, correct? 3. And this additional fuel load is a direct result of better wing aerodynamic performance, which would make the aircraft take-off and land on shorter distances with the original fuel load; or the same distances as before for a higher fuel load, correct? 4. And the 1% improvement in fuel burn also contributes to the increase range in conjunction with the additional fuel load, correct?

            I hope I have not exhausted your patience…

          • All correct with the caveat that on 1 you don’t change fuel capacity but MTOW which makes you capable to fill more fuel for a max mission. The wings fuel tanks are large enough not to go fuel limited in any weight variant.

          • “The wings fuel tanks are large enough not to go fuel limited in any weight variant.”

            Do you think that could include the CS500? In other words, do you think the CS500 will be able to retain the same kind of range?

          • The wings chould be OK for CS500 including the tankage. It won’t be the series long ranger but it should be OK.

          • That means the CS500 will have slightly less range than the A320neo and 737 MAX 8. It may also have less seats as well; but that is harder to guess because we still don’t know what BBD will, or can, do with the Cs100/300 wing.

          • Has the CS100/300 got some increased range out of better tuning of the fly by wire system, this could include more lift for decreased thrust ?

          • Probably, according to Dewar they have been conservative in all domains, it was their first really own larger design with a lot of unknowns. Aero had margins, systems had margins, weight had margins (which they used and then some but not more than normal) they could now release these for a better specced aircraft.

          • What is particularly interesting is that this new option “will allow a CSeries operator to carry a heavier load of passengers and cargo, or more range or some combination of the two.”

          • Adds roughly 165nm or more weight. Do you think it would be enough for the CS500?

          • Based on the above discussion I had with Bjorn I would say yes, it might be enough to keep the CS500 within reasonable distance from the A320neo/737-8 in terms of range. It’s rare to find so much margin before EIS. The basic C Series was already impressive, but when we add the recently announced increased MTOW and this new engine option we have many reasons to be optimistic. One thing I like is the flexibility the C Series offers to potential customers in terms of engine options for each variant.

    • The payload and fuel load cannot exceed the Maximum Take Off Weight (MTOW) of each variant. The range and payload indicated for each variant is therefore the standard maximum range/maximum payload combination for the allowed MTOW. If there is room to put additional fuel the aircraft may have to leave some seats empty in order to stay below MTOW.

    • Ted,

      thanks for asking the right question.

      The fuel for all these models are the same, 20.8t/46klb, save for -900/9 which has an ACT and therefore 22.4t/49.4klb. The fuel limited models are -800/8 and -900/9 and there you don’t lose many nm for an increase in Payload/OEW. Check their ACAP diagrams or the one for 777-200LR in my article to understand why.

      I did the checks and saw that Boeings numbers were OK, then twisted it the wrong way when typing, fixed.

  4. Dear Bjorn,
    Thanks for your post. Just a couple of comments:
    BCA stands for “Boeing Commercial Aircraft”, not “Boeing Civil Aircraft”.
    Other that comes at a first glance – yes, cost per seat is a quick metric for airline personnel concerned with the cost or purchase of an airplane, typically finance and management team.

    But Boeing Marketing keeps fluid channels of communication with all relevant functions in airlines. For most of these, operational cost is the concern, with its most relevant metric the “cost per seat-mile”, since the “seat-mile” is the basic unit of production in transportation (which includes air-transportation).
    S-M cost is therefore the basic unit of transportation productivity, and it can be made to include ownership cost (cost of loan to purchase aircraft, insurance and depreciation).

    • Thanks Javier,

      my bad, BCA is corrected and when I say cost per seat I of course mean cost per seat-mile, have changed that as well. The seat-mile cost is highly influenced by a ruleset. I have seen good economical studies for operational costs which has got a 7% skew in the last step from cost per aircraft mile to cost per seat-mile because of sloppy treatment of seating standards.

      I therefore appreciate how important it is that things are compared under a strong common ruleset. That an OEM has a strong consistent ruleset as a base makes you know his viewpoint and its base facts, its a good start.


      • Actually, I believe BCA is Boeing Commercial Airplanes. 3rd time’s a charm. 🙂

        • We actually have two BCAs, hence the confusion:

          1. Boeing Commercial Airplanes
          2. Bombardier Commercial Aircraft

  5. Long overdue. I remember the rules used by Boeing were totally out of line already a decade ago. Specially on larger aircraft they did magic with e.g. CASM.

    E.g. The 467 seats for the 747-8 were happely copied by analysts, blogs, forums for a decade comparing it to 525 for the A380. Non-sense of course. E.g. this old 80k post.

    Leeham knew better and did their best to do apples to apples and we have to applaud them for that objectivity. Others like VeroVenia were putting their heads willfully in the sand, because they preferred the resulting efficiencies, must be embarrassed now Boeing themselves admits he numbers weren’t right (anymore). They missed an opportunity to show profesionalism and objectivity.

    • Does seem strange that the seat counts have dropped on the widebodys, except for 787 .
      The 787-8 has ‘gone down’ from 242 3 cl to 242 2cl.
      For the 787-9 the 2cl numbers go up by 10 but the bigger 787-10 only goes up by 7 ?
      Iam I reading something the wrong way.

      • I should have to do with the ratio changes we talked about in the article. Before Boeing (and e.g. Airbus) could keep the same business class size for 788 and 789, now they change the size of the premium classes to have the same ratio to total. This creates these differences.

        • Just looking at ANA who do fly 3cl 787 they have 169 seats not 242 and in their 2cl 787-8 they have 152. They have 4 versions of 788 yet only one comes close to 242 seats. And their 789 is in ultra high 2 cl domestic seating at 395.
          I still think Boeing is manipulating its ‘standard’ to keep the 787 close to previous number

          • If you cared to look at those LOPAs you would have found the answers instead of supposing someone is cheating. ANA is using huge J sections and/or 8 abreast Y sections. The Boeing IAC used old style seats and pitches in F and J to reach 242 for a 3 cl LOPA, that is why they update to Standard. Now they use relevant seats and pitches in 2 cl to reach 242, we reach 238, neither is cheating. Do the homework and you will see, it even includes ample long range catering, around 35 CARTs, each taking 80% of an Y seat.

          • I did see ANA have some large premium seating areas, but I mentioned the higher end of the seating numbers too. With British Airways the 788 is 214 seats , with LAN its close to Boeings numbers (247) but not aisle access for all flat beds.
            United 788 is 219 seats but not flat bed.
            Air India flat bed but not all direct aisle access 256 seats. Ethiopian is 270 seats.
            China Southern has a tiny first class and 228 seats.
            Air Canada is 251 seats but not flat bed

            Where is this mythical 242 seater with flat bed , direct aisle access 2 cl ?
            Boeing has created a ‘new standard’ that has become outdated on day one. Where is the econ plus ? In reality they should have dropped the seat count but couldnt for marketing reasons, its not cheating but choosing your goalposts carefully

          • Air Canada does indeed have flat beds (and aisle access) in J, 20 of them, plus a small three-row premium economy section, and then cattle class with the dreaded 787 nine-abreast seating.

            251 (for 788) and 298 (for 789) are actually slightly higher than B’s numbers in spite of the premium economy section.

  6. Wow KarelXWB, you were raked over the coals in that thread. I see this as a non issue since carriers don’t use the figures from OEM’s to plan their respective seating arrangements and to date, as far as I know, a RFP has not tilted suddenly because of outdated figures. It’s not like buying a car where the seating capacity in a sedan is and always 4-5 seats but what the buyer can change or options like better engine, better sound system, different transmission, stronger engine etc. This is only a timing issue, not a professionalism or dishonesty issue.

  7. Lol

    A) Boeing knew, they just decided to not to change the data. Why, we’ll never know.

    B) “Cooking the books” is a fraudulent accounting practice where the numbers are manipulated to mask losses to reveal inaccurate profits. Doesn’t apply here.

    C) Perhaps you don’t understand

    D) There’s only one C in the English alphabet. =)

  8. “For business it is around two times.”

    About three times. Twice the pitch and 20-33% better seatwidth. E.g 6 abreast iso 9 abreast. New flat sleep 80 inch configurations give in leg space width. Direct aisle access for all takes more room. Business class takes at least tripple as much space as an economy seat today.

    Smaller twin aisles seldom have First, even width BA, AA, SQ, CX, EK and AF. Assuming two class is more realistic.

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