Sixth Freedom

After years flying on BA operated aircraft I know almost nothing about BA's engines or their wheels and brakes and am keen to erase this gap in my knowledge.

In particular I would love to learn about the economics of these vital parts of the aircraft, but as I am not really sure where to start I thought I would turn to the good folks on the BA board. So far my knowledge is limited to:

Engines: more horsepower consumes more fuel, which is inefficient unless you are operating one or more of high, hot or heavy - otherwise nothing

Wheels and brakes: nothing, apart from cost per aircraft landing being a key metric

The fleet facts page on ba.com tells me what the engines are but since I know next to nothing about engines (yet!) it is not clear to me why they would be chosen. For example, the A321 uses IAE V2500 engines and some of the 777s use the GE90. Why did BA select these models? Comments and guidance about other aircraft and why their engines were selected are welcome too!

Wheels and brakes seem a little more obscure. Where should I begin?!

Many thanks in advance!

Stez

Welcome back 6F, you've been quiet.

IAMORGAN

I knew that when I saw a post by Sixth Freedom it would be interesting, and it certainly is an interesting topic. I'm not going to add anything of value other than to say I recall *something* about A380 engines being a different spec to QF. There was some discussion about RR Trent 800? series engines when QF had the uncontained engine failure and the fact QF were using an uprated version. Expected routes must be one factor (IE do you think you're going to be using your A380s to do puddle jumps to Boston or 15 hour stints from Dubai to Melbourne or hot and high like Mexico etc). Maybe Alex the engineer can comment before he leaves / escapes for pastures new ;-)

dera

With engines, you are limited to what engine options are in the type certificate sheet for that airframe. For example, with the A32S, You have 2 main options (I think there's 4 total but no-one really uses the PW or LEAP engines) BA is one of the few operators that chose the IAE engines - most operators use CFM56. One jet engine costs 7(IAE) or 8(GE90) figures so choosing which one to use and operate isn't a simple decision.
I don't know if BA owns the engines, often they are on a separate lease. An airline of BA's size might own/lease 1-2 spare engines for the 32S airframes.. I doubt they have spares for the widebodies.
One engine has a limit of hours/cycles, after that they have to be overhauled/hot side inspected, this on top of the routine maintenance. It's a very bad(expensive) day if a major engine part gets rejected at overhaul. Operating jet engines isn't for the faint hearted. One fan blade (that is - one blade of the big fan you see at the front of the engine) is 30-40k. An overhaul is a few million, depending what parts pass the inspections and what need to be renewed on top of the standard items that need to be replaced to legally call it an overhaul.

Tire maintenance is usually done on condition. I think one tire/tube costs around 15k. The approved maintenance program will define which inspections/time limits are on the brakes/wheels. One whole landing gear assembly cost is somewhere around low millions. There's a cycle limit for them, after which they have to replaced/overhauled (most often they are overhauled).

Hope the engineers in this forum add more knowledge and fix the errors I might have made...

littlefish

.. and a welcome back to the blazered one from me .
Engines are a different order of magnitude to the wheels/brakes. The economics typically, think engines, draw from the certainty of the task and technology. So a mythical A360 (engines contract) would be looking at high risk premiums, whereas upgrading 737 series to neo would have a lesser risk. Your economics probably draw from that point and asking the right questions about who (of potential suppliers) can deliver what +/- versus their competitors. With that 'in the bag' its then back to how to estimate full life costs incl fuel usage.

I guess someone from BA eng might come along and flag some of the less stellar choices BA have made here, and why it seemed a good idea at the time.

Greenpen

Engines! Brakes! Who cares? It's soaring like an eagle that gets me going!

ShuttleRunner

Interesting post... to which I have many insights. Tyres, wheels and brakes are a bit easier to explain - engines a different ball game entirely! I have experience of the BA fleet both as an ex-BA engineer and now as someone who works with a good portion of the BA fleet, albeit in a different capacity.

Wheels/tyres are done on condition usually, or, like with breaks when they reach their shelf life, which may be a certain number of flight hours or (usually) flight cycles. When I was there brakes, tyres and wheels were overhauled in-house at British Airways Component Engineering (BACE) in Hayes - not sure as to the fate of these departments as I know a lot of in-house overhaul has been cut in recent years. Used tyres are scrapped, but wheels are overhauled and NDT'd (non-destructively tested) to check for any issues. In terms of brakes I know they had the capacity to overhaul the electric brakes used on the 788/789, but not much more from that side.

Engines are more my area of interest and there are so many ins and outs to it. An airline may have a choice of engines, and they are generally chosen based on performance, although commercial has a lot of say in it too - may get a better deal from one manufacturer than another, much like buying a car, with service packages/fleet hour agreements etc. thrown in (RR TotalCare, Power by the Hour etc.). It is generally easier to manage one type of engine per fleet - they are very needy assets and require a lot of management, especially with a mature fleet. I can't imagine tending to 300-odd V2500s or the RB-211 fleet is an easy task... Every engine type has its own set of nuances and issues, which are generally available in the public domain via Service Bulletins from the OEM, and these vary by fleet maturity. Engines are sent for overhaul either if there is an event - stall/surge investigation, MCD catch (when very specific metal/metal flakes are picked up during regular oil checks (this is done in-house at BA) or the limited life parts inside the engine need a full stack replacement when they reach a certain number of flight hours. Engines are generally owned by BA themselves, an engine lessor, finance company, or as part of a total aircraft lease package - and the maintenance of each type will be slightly different. I could go on all day...

Farringdon

I can't add anything specific, but perhaps I can at least point you in some helpful directions. There has been a lot of coverage in the business press about the choice of engines for new aircraft models - I've read a lot in the past on this topic about the 380 and 737neo. You should also look at the financials for the companies that make the engines and other parts. Obviously RR but also people like Safran. Also see if you can get your hands on the analyst coverage of those companies.

Stez

Reading on the above answers, if two engines of the same type is subjected to two different flight regimes - long engine hours, few cycles and those with short engine hours but many cycles, which one would need more inspections or overhauling sooner?

I know for airframes that cycles are quite important factors.

ShuttleRunner

Engine life is measured in cycles also, and the requirements will be the same for the same engine type flying different regimes. For example, in the short haul fleet there are mid-hauls and short-hauls, where the mid-hauls will generally be flying longer sectors. The engine is limited by X number of cycles, where it becomes a legal requirement to remove it and overhaul it. Outside of these conditions, engines are removed based on condition - it may be that an engine on long sectors won't last as many cycles of that on short sectors, but there is nothing stopping it doing the same amount of sectors. What I have seen with the IAE engine is that some are multi-rated, and so can operate with anywhere between 22-33k lbf of thrust (depending on A319, 20, 21 etc. and engine variant), and generally those that have a larger thrust rating (A321 for example) will not last as long as the others as they are subjected to more stress.

1010101

I am curious on one point for the engine folk, in some cases a larger car engine can be more efficient. For example a 100hp engine uses x amount of fuel at 4000rpm to maintain 60mph. Sometimes a 200hp engine may be able to use 2000rpm to maintain 60mph and use less fuel in the process. Does the same thing apply to jet engines? Do higher thrust variants require less effort to maintain the same performance?


Commercially i know a little bit about this. Engine selections are often political, for both the airlines and particularly the manufacturers. Increasingly Boeing/Airbus are going for a single engine type on their aircraft, and funnily enough so far Boeing have only selected American manufacturers and Airbus have only selected European manufacturers. If you buy a 77W/77X you have to have a GE engine and if you buy an A350/A330Neo you have to have the RR Trent.

simonrp84

.....

florens

Only 1 or 2 spares for such a large fleet? Even LX had a spare GE90 for their 777 with a fleet of less than 10 frames.

flatlander

​​​​​​
​​​​​Though that does seem few for a fleet the size of BA's, there are additional spare engines held by manufacturers in strategic locations, which can be supplied to customers in need. This is often relevant because arranging long haul transport of done engines in some configurations (with fan) at short notice is hard; they are so large, in particular so wide, that they require specialist cargo aircraft ( 747F nose loader or Antonov) which can take a few days to arrange.

Land-of-Miles

Doesn't BA just get whatever is being offered in India as that is cheapest