Bjorn’s Corner: Engine rubbing

By Bjorn Fehrm09 October 2015, ©. Leeham Co: Last week an Airbus A320neo prototype with Pratt & Whitney’s (PW) GTF had a problem while testing hot and high conditions at Al-Ain airport in Abu Dhabi. The engine suffered a rubbing problem and PW and Airbus decided to replace the engine before returning the A320neo to Toulouse.

I had the opportunity to discuss what happened with PW people at ISTAT this week and decided it makes for a good follow up to our two other engine Corners to write about what happened and how serious it was.

The problem was compressor blades rubbing against the compressors stator wall. PW knew that this engine individual could have that problem. They saw when assembling the engine it was a bit tight in the compressor area. PW said they told Airbus there was a risk with this particular unit, and sure enough, there was rubbing to be seen when they boroscope checked the engine after the test.

Here what it was all about and what to do about it. Read more

Bjorn’s Corner: Engine ratings

By Bjorn Fehrm

By Bjorn Fehrm

02 October 2015, ©. Leeham Co: After the article about the role of bypass ratio on a turbofan’s efficiency, we now look at other aspects of civil turbofan engines that are worth some light. It’s about how the engine OEMs create different versions of the same engine to cater for different aircraft variants.

The aircraft OEMs create different size variants from the same base model of aircraft by means of stretches. There is no better example of that than the Boeing 737. Over the years it has had more than 10 major versions. For the present in-service series, 737NG, there is three official variants, from the -700 to the -900ER. Originally it also had a smaller -600 variant.

These require engines from 20klbf to 27klbf. How this is achieved and what it means for engine characteristics and reliability is the focus of today’s Corner. We will also compare it to a typical long range engine, the Rolls-Royce Trent 1000/7000, which powers the Boeing 787 and Airbus A330neo.

Read more

Evaluating airliner performance, Part 2

By Bjorn Fehrm

Subscription required.

Introduction

Sep. 24 2015, ©. Leeham Co: In the second part of our series about comparing and evaluating economic and operational performance of airliners, we look at the parts beyond fuel that make up the Cash Operating Costs (COC) for an airliner.

While fuel consumption, crew costs and aircraft maintenance costs can be evaluated in a way which closely resembles reality, other costs in the COC are too complex to model in their true form.

This is the case for underway or airway fees, landing fees and station fees. Here, just about every country/airport in the world has taken the liberty to invent its own charging principles and formulas.  With several hundred different formulae for these charges, the way out is to use industry-accepted approximation for these costs.

Summary:

  • We establish how crew cost are modeled for our evaluation missions, taking into account the complex world of work time regulations for pilots and cabin crew.
  • We also describe how we handle airframe and engine maintenance costs and how these get allocated to our missions.
  • Finally, we describe how the complex underway and landing/station costs are modeled with the accepted approximations these require.

Read more

Bjorn’s Corner: USAF Tanker program

By Bjorn Fehrm

By Bjorn Fehrm25 September 2015, ©. Leeham Co: When Scott Hamilton asked me to give my view on his article “Pontifications: Duelling refuelling tankers” I accepted. I was not involved in the project and was only following it casually over the years.

I will also not give my view on what would have been the most suitable tanker for the US Air Force. I simply don’t have the relevant military competence for that, having never operated my fighters with aerial tanking nor been in an aerial tanker aircraft.

Where I have relevant competence is in writing military specifications for important aircraft procurements and the excerpts I have seen from the tanker RFQ on key specification points don’t impress. Let me explain.

Read more

Evaluating airliner performance, part 1.

By Bjorn Fehrm

Subscription required.

Introduction

Sep. 21 2015, ©. Leeham Co: Comparing and evaluating operational and economic performance of competing airliners is a complex task that requires analysis of thousands of parameters.

It’s not unknown for smaller airlines to have limited capability to undertake these difficult analyses. Accordingly, they often rely on the Original Equipment Manufacturers (OEMs) for their analysis on behalf of the potential customer.

Unfortunately, the OEM’s have little incentive to provide an unbiased view of either their products nor those of their competitors.

Thorough evaluations require quite some preparations. If these preparations are not carried out correctly, the result can be biased to the extent that the evaluation method dictates which’s the best aircraft and not the most suitability aircraft for the task. We will in a series of articles cover how aircraft evaluations are done and how evaluation pitfalls can be avoided.

Summary:

  • Aircraft evaluations are made for all direct operating costs that can be linked directly to the operation of the airliner.
  • The costs can be divided in Cash Operating Costs (COC), which covers the operation of the aircraft and capital costs. Combined these costs constitute the Direct Operating Costs, DOC.
  • The OEMs produce data for all COC cost items, but they do that in their own way. To make the costs comparable one need to know and understand their assumptions and neutralize these through independent modeling of the costs.
  • We describe what these assumptions are and how to neutralize them.

 

Read more

Rolls-Royce and Safran, major European engine OEMs with different fortunes.

By Bjorn Fehrm

Subscription required.

July 30, 2015 © Leeham Co. Rolls-Royce and Safran, the parent company of CFM partner Snecma, released their Q2 and first half 2015 earnings today. It is interesting to compare these companies as they are in different strategic situations in their dominant business segments, civil turbofan engines.

Civil turbofans constitute 52% of Rolls-Royce total business whereas it makes 54% of Safran’s turn over. Rolls-Royce’s focus has been widebody engines to the point where it exited its part of International Aero Engines, which makes the single aisle V2500 engine, three years ago. Safran on the other hand is heavily invested in the single aisle market through its 50% part in CFM through its Snecma subsidiary.

The present situation and the future outlook for these two companies are intimately aligned with this strategic difference. We look at why and how this will affect their immediate future.

Summary:

  • Rolls-Royce is experiencing migration problems in its widebody turbofan business. Its bread and butter Trent 700 engine is on its way out and it takes until 2018 for the replacement, Trent 7000, to kick in.
  • Other programs are only growing slowly: the Trent 1000 for Boeing’s 787 or Trent XWB for the Airbus A350.
  • Safran civil turbofan business Snecma is enjoying record sales and deliveries through its CFM joint venture with GE.
  • Despite sharing its revenue 50:50 with GE, the business turnover is the size of Rolls-Royce turbofan business today and larger tomorrow. Profit margins are three times higher.

 

Read more

Options for Singapore Airlines to operate direct flights to the US, part 2.

By Bjorn Fehrm

Subscription required.

July 23, 2015 © Leeham Co. After having looked at Airbus’ A350-900 and Boeing’s 777-200LR for filling Singapore Airlines (SQ) need for an Ultra Long Haul (ULH) airliner we now complement the analysis by including Airbus’ and Boeing’s up and coming A350-1000 and 777-8X.

Singapore Airlines has 70 A350-900 on order to replace 25 Boeing 777-200ER. There would also be place in that order to replace the 25 777-300ERs that Singapore operate, most likely with the A350-1000 (SQ has the right to change model).

The 777-8X is Boeing’s replacement aircraft for 777-200LR and direct competitor to A350-1000. It is interesting to compare these two types flying the Trans-Pacific routes non-stop from Singapore to US that we flew with A350-900LR and 777-200LR and to compare the per seat fuel consumption versus the smaller aircraft.

Summary:

  • The 777-8X and A350-1000 are a sized larger than both 777-200LR and A350-900LR, and can therefore transport more payload.
  • The 777-8X is designed as an ULH aircraft, the A350-1000 not. We explore what this means for the US missions.
  • Flying to the US which of these four aircraft will be the most efficient? And carry an interesting payload?

Read more

Airbus A380neo not yet a project

July 21, 2015: The London Sunday Times created a stir over the weekend when it headlined an interview with Airbus Commercial CEO Fabrice Bregier that Airbus “commits” to an A380neo project.

Drilling down into the story and checking with Airbus, as well as going back to Bregier interviews at the Paris Air Show and one we did with him at the IATA AGM in early June, it’s clear the Sunday Times was somewhat exuberant in its headline.

Read more

Bjorn’s Corner: What Paris Air Show taught us about East and West.

 

By Bjorn Fehrm

By Bjorn Fehrm

25 June 2015, © Leeham Co: With a few days in the office one can look back at Paris Air Show with a bit of perspective. So what are the impressions?

It was surprising how many orders Airbus and Boeing landed. Both had played down the expectations, telling that it will be a decent show but nothing close to record. Yet both were booking orders or commitments which were better than expected going into the PAS. Read more

Pontifications: Final thoughts of the Paris Air Show

Bu Scott Hamiltn

By Scott Hamilton

June 22, 2015, c. Leeham Co. The Paris Air Show was largely as expected, with a few small surprises. Boeing did better than expected via-a-vis Airbus, actually leading slightly in firm orders and tied in orders-and-options going into Thursday. This is virtually never the case, particularly at the Paris Air Show, Airbus’ “home” turf. At the same time, some Wall Street analysts noted the firm orders fell below expectations. I’m not especially concerned about whether an announcement was firm or a commitment, because the latter typically firm up, if not within the current calendar year then usually in the next. Note, for example, Boeing announced the launch of the 777X program at the 2013 Dubai Air Show was some 200 commitments, or thereabouts, but the orders didn’t firm until 2014. Airbus announced a commitment for 250 A320s from Indigo in 2014 and it will likely be firmed up this year.

Read more