8 Things You Probably Don’t Know About Jet Engines

You’re in an aircraft taxiing to the runway. You stop momentarily. Then you hear of the swelling roar of the engines, the aircraft vibrates as it accelerates, pushing you back gently into your seat. The scenery whips by faster and faster until you leave the ground. You’re airborne! All of which would be impossible without the powerful engines.

These extraordinary powerhouses are fascinating, even to those who work with them on a daily basis, which is why we’d like to share some facts about them with you.

1. How powerful is an aircraft engine?

The power of a jet engine is equivalent to that of 28 Formula-1 racing cars. No wonder the grease monkeys and thrust junkies at KLM Engine Services are crazy about them.

2. What is the biggest aircraft engine in the world?

General Electric’s GE90-115B, with a diameter of 3.25 metres, generating 115,000 pounds of thrust, is currently the biggest in the world. You’ll find these big boys hanging under the wings of KLM’s Boeing 777-300s, which are easily recognisable because they are all named after world heritage sites, such as the Yellowstone National Park.

 aircraft engine

3. It’s like taking your car to the garage, right?

When you buy yourself a new car, the manufacturer recommends that you should have it serviced regularly. It’s up to you, the owner, to decide whether you heed this advice. But that’s not the case in aviation. Maintenance, checks, modifications – they’re all mandatory. Airworthiness authorities like the FAA or EASA closely monitor KLM and other aircraft operators to ensure that all maintenance is done on time and as instructed.

And whereas car maintenance is based on distance driven, aircraft maintenance is based on flight cycles and hours flown.

4. What is a flight cycle?

Engine life is measured in flight hours and flight cycles. One cycle = one take-off + one landing,

So, a one-way flight from Amsterdam to New York amounts to around 8 flight hours and 1 cycle (i.e. one take-off in Amsterdam + one landing in New York). A roundtrip between Amsterdam and New York would amount to 16 hours and 2 cycles.

 aircraft engine

5.When does an engine need servicing?

Every engine must undergo minor or major maintenance after a set number of flight cycles. This varies depending on the engine type. For instance, the CF6-80E, which powers KLM’s Airbus A330s, requires major maintenance approximately every 7,300 cycles and minor maintenance every 200 to 400 cycles.

6. Just how big is the “garage”?

Our “garage” is as big as six football fields, approximately 40,000 square metres.

7. How long does it take to disassemble and reassemble an engine?

KLM has its own maintenance department and its own Engine Shop where jet engines are maintained and overhauled. There’s a reserve engine for every type that KLM operates, which means they can be immediately replaced if maintenance is required. Our technical crews can replace an engine in around 24 hours.

The engine that has been removed for maintenance – the “dirty engine”, as we call it – is carefully packed and transported to our Engine Shop. Depending on the engine type and the required maintenance, it will be as good as new and ready for flight after 50 to 60 days. It bears mentioning that KLM Engine Services also services engines for other airlines.

8. What does an aircraft engine cost?

That’s an interesting question, but it’s surprising difficult to answer. Most aircraft are fully equipped with engines when purchased, so you could say it’s a package deal. And then there are so many different types of engines, which each have their own thrust rating. Say what? Thrust rating, but let’s leave that for another blog. Roughly speaking, an engine can cost anything from 12 to 35 million dollars.

Impressive right? If there’s anything else you want to know about engines (apart from the secret of thrust rating), please let us know!

Sounds familiar?

It’s quite possible you’ve heard or read this before. We’ve posted this blog in March 2015. So this actually is a repost. But let’s be honest: you can never know too much about jet engines, can you? :-)

Join the conversation Show comments


Its always good to read posts like this. But I have a question. If you Dont have any General Electric CF engines in stock but you have a Rolls Royce Trent with the same specification in stock can you run a mixed configuration?


Dear Stephen, thank you for your response.
An aircraft is certified to operate with a specific engine type. Therefore it is not allowed to operate with a different engine type. Luckily we have spare engines in the correct type and configuration :-)

All the best, Miranda

Alexis Novratidis

Why does some plane have like 2 small engine on each wing and other planes have 1 big on each wing? What is the best and safest? I feel like the ones with 2 engines on each wing is best cause If one engine faluire u still have one engine on each side. I Hope u understand What i mean // Greetings Alexios:-)

Alexis Novratidis

I mean like the 777 and The ilyushin ruby star, the ilyushin has 2 small engines while the 777 has 2 huge engines (the planes is almost the same big)


Dear Alexis,
Thank you for your response,
the number of engines is mainly a decision of the manufacturer and is part of the design of the aircraft. Whether there ar 2 or 4 engines has no impact on flight safety. The operator can determine the type of engine though, which depends on the flight path/destination. By the way, the new generation engines are more efficient than its predecessors. the etops certification (Extended-range twin-engine Operational Performance Standards) allows the twin-engined aircraft to fly long-distance, a good topic for a next blog. I hope this answered your question?
Kind regards,

John Rhimbo

“…Whether there are 2 or 4 engines has no impact on flight safety…”???!!!!

What moron wrote this…?

JT Allen

Alexis, you would think 4 engines would be better than two, but a Boeing 777 can fly extended ranges on just one of it’s two engines. All modern aircraft are extremely safe.

Jason Miller

2 engine on one wing airplanes (il-96) are much safer, however in aviation all engines undergo the same rigorous testing for durability and etc. In the case of the one engine on each wing airplane (777) if one engine ever does fail the other engine is more than capable of keeping the plane in the air on its own

erik Dam-madsen

Instead of 115,000 pounds of thrust, could it not be explained in W or horse power.
Will be more easy for outsiders to understand


Dear Erik,
Thank you for your comment. We choose differently, but horse powers could have been a good way to explain as well.

All the best, Miranda


Uitleg Thrust naar PK.

De pk (paardekracht) is de hoeveelheid kracht die een gewicht van 1 kilogram in een tijd van 1 seconde over een afstand van 1 meter omhoog trekt. Nu we dit weten kunnen we aan de slag met de stuwkracht van bijvoorbeeld een een straaljager.

Een pound is ca 0,454 kg, wat dus betekent dat 1 kg ongeveer gelijk is aan 2,2 pounds. Rekenen we de pounds terug naar Newtons, dan krijgen we weer die 0,454 x 9,81 = 4,45 N (afgerond).

Nu nog even de meters naar feet omrekenen…. waar hadden we dat ook al weer eerder gelezen ? ….Kijk eens op : http://www.natuurwetenschappen.nl/modules.php?name=News&file=article&sid=1016 En daarna ook nog even op : http://www.natuurwetenschappen.nl/modules.php?name=News&file=article&sid=1033 voor de conversie, En het rekensommetje is snel gemaakt.

We zien dus dat 1 pond stuwkracht ongeveer gelijkstaat aan 4 pk. Een beetje straaljager heeft zo’n 7000 pond stuwkracht wat dus betekent dat je de beschikking hebt over zo’n 28000 pk.


De paardenkracht is een gewicht van 75 Kilogram in 1 Seconde 1 Meter omhoog verplaatsen. Dan valt de berekening iets anders uit.

Leroy Drost

The 777 engine (GE90-115B) produces approximately 87000 horsepower or 65MW(electrical power)



A jet engine does not provide power the same way as a car engine. That’s why you can’t express it’s power by horsepower or kW. It’s all about thrust.


Well, sort of… (RR T56 tech here) we measure ours in HP, direct drive turboprop engines and measure is Shaft Horse Power, we got 4600 SHP out to each propeller… It’s still a jet engine, difference beeing ours drive a propeller that can change its blade angle and having a torque measuring device between, and your typical high bypass turbofan “airliner” engine got a jet engine driving a multi-blade fixed pitch propeller (fan) inside a fancy tube (duct) :) Rough estimates would indicate a GE90 pushing along a 777 at cruise speed must generate about 29000hp each, and more than that at full power so “28 F1 engines” as mentioned in the blog might be a bit shy infact ;)


Thank you Dave :-) Indeed it is all about thrust. You just inspired a new blog!

Varun rikhi

It’s very interesting and information


Thank you Varun.

All the best, Miranda

peter Jongeneel

Good day
My car (ROVER 75 CLUB V6) is using 1 liter for every 13 km, can you tel me aprox how much those gians use for a km or Mile
thank you for your answer
Peter jongeneel


Hello Peter,

We measure in pounds/hour (weight). But is approx 3L at take off for one engine cf6-80c2. But there are a lot of variables.


Sorry a second that is


At a cruising altitude of 35000ft at 490 knots of ground speed with 300 passengers that engine accounts for approximately 2.4L/100km (both engines). That fuel flow steadily decreases as the aircraft approaches its destination. We’re talking about an average of 2L/100km.

Sulaimaan manack

Usually, most engines use about 2 liters per passenger per 100 km.


That right ….. only 2.4 litres per 100 km ?!?!
That is frugally efficient!

Jan Reijnders

Ik houd van het vliegen in de BC, maar die tickets zijn erg prijzig. Een groot gedeelte van de kostprijs van een vliegticket zit in de kosten van kerosine. Daarom mijn vraag:
wanneer gaan vliegtuigen vliegen op zonne-energie? Immers, boven de wolken kan men 100% profiteren van deze gratis energie.
Met vriendelijke groet,
Jan Reijnders
Eersel, Nederland


Dag Jan,
Wij vliegen ook graag in de KLM WBC en dit is inderdaad niet de goedkoopste reisoptie. Het zou fantastisch zijn als het toepassen van zonne-energie dit product toegankelijker zou maken. De wetenschap, waaronder de TU- Delft, onderzoekt de mogelijkheden van toegepaste zonne-energie in de luchtvaart. Of en wanneer vliegtuigen op zonne-energie mogen gaan vliegen is op dit moment nog niet te voorspellen. Maar het is zeker een mooie gedachte.
Met vriendelijke groet, Miranda


Ik ben bang dat volledig op zonne energie vliegen technisch niet mogelijk is en altijd een droom zal blijven.

De zon levert ca 1.3 Kw aan energie per m2/sec bij loodrechte lichtinval; dit is de zg zonneconstante
Hier zul je het dus mee moeten doen, meer energie zit er simpelweg niet in; is een gegeven.

Als je de hiervoor genoemde GE-90 met 29000 PK even als voorbeeld neemt:
29000 Pk = 21750 Kw
Deel dit door 1.3 en je hebt dus 16730 m2 oppervlakte nodig om die energie onder de meest ideale omstandigheden op te kunnen wekken.
En zelfs dan is het een theoretische waarde, want ik betwijfel of we ooit een rendement van 100% zullen halen.
En dan praat je over 3 voetbalvelden …. per motor….


Vergeet niet dat de zon niet altijd schijnt ;) stel dat je vertraging oploopt en je toch na zonsondergang moet landen, dan heb je een probleem. En in de winter is de vliegtijd dan zeer beperkt.


Daar hoef je je dan niet druk om te maken dit zal meer om een toepassing gaan voor emergency lighting of accu laden op zonne energie denk ik . Als het vliegtuig op cruise hoogte zit dan is hij al boven de wolken dus zal hij niet weersafhankelijk zijn .

ian stone

Hi great that KLM are on face book was just wondering what thrust setting would normally be used at max altitude on the 777 thanks ?

Sulaimaan manack

Well, engines are rarely run up to full throttle. Fully loaded 777’s are usually opened up to about 80% or so. Combine that with the fact that most engines are most efficient at cruising speeds/throttle settings, and you really end up with very little waste of resources.


Plz can you tell me what is the highest speed can a aircraft hit ?
Thank you


Mach 0.84 at cruising altitude of 35000ft, that is 84% the speed of sound, which at normal conditions is equivalent at 905km/h or 560mph or 490 knots.

There are exceptions where the aircraft can ”fly” faster, that is when for example at cruising altitude the wind blows on the direction of your flight path. I’ve seen 120 knots of wind at 35000 feet which can speed your ground speed at speeds pretty close to 1000km/h. Nevertheless the aircraft itself doesn’t withstand extreme forces since what accounts for the flight dynamics are the speeds of with the air hits the wings.


That’s the difference between airspeed and groundspeed


You fly through the air, not over the earth’s surface. An aircraft needs an airflow over the wings to generate lift. For example an aircraft needs a wind speed of 100 knots to take off, if the wind blows 20 knots right on the nose, the aircraft has to speed up only 80 knots over the runway to get a 100 knots wind over the wing. That’s why all aircraft take off and land with headwind.

In the case of the prementioned take off situation, the airspeed is 100 knots and the groundspeed only 80 knots. It’s an advantage in takeoff, but when airborne a tailwind is of course favorable. Imagine flying over the Atlantic with 450 knots airspeed, a headwind of 100 knots results in a groundspeed of only 350 knots. A tailwind of the same speed results in a groundspeed of 550 knots!

Emre Yurttas

Can I ask what engines your 747-400 aircraft uses


Hi Emre,

Thank your for your response.
KLM’s 747-400 fleet is powered with GE CF6-80C2 engines.

All the best, Miranda

Hans Bakker

Having an CF6-80E1 operating between shopvisits 7,300 cycles is somewhat ambitious to call ;<). We have never seen an engine making such figure on wing between heavy maintenance. Depending on the Flight Cycle Ratio (FCR) when being very low an engine could come as close as 4,000 – 5,000 Cycles On Wing. But with higher FCR this figure gets less and simultaneaous Time On Wing figure gets larger.
Maybe the text can be explained as an engine requires maintenance which stretches between A-check interval inspection and the Life Limited Part lowest life limiter which requires maintenance to replace the lowest limiter. In between these two extremes all kinds of maintenance can occur such as: Quick Turns, Performance Restoration Shop visits etc.


Hi Hans, you totally understood what we’ve intended to say. Thx, Miranda


Hi Hans, you totally understood what we’ve intended to say. Thx, Miranda


What a wonderful blog, thanks a lot!

My question is about intake of water/hail.
How is it possible that jet-engines operate whilst flooded with rain and hail at very high speeds ?



Aircraft engines are designed, build and tested to continue operations in heavy weather conditions. Any water ingestion, even if its frozen, is compressed extensively during operation of the engine. Therefore hail or rain doesn’t effect combustion.
All the best, Miranda


and rain consists not only out of water it haves also oxygen, so the combustion and power will increase during rain.(older airplane did have water injection in the inlet for more power in hot conditions and have at temp conditions for power)


Not bad at all fellas and gasall. Thanks.


The engines igniters can be switched to continuous ignition meaning that if a flame out occurred there could be recognition instantly, and the engines computer is full with logic to enable it to re ignite.


As soon as I inaltiily commented I clicked on the Notify me whenever new comments are added checkbox and now each and every time a remark is added I get four email messages with the exact same comment.


Che differenza in potenza (libbre di spinta) c’e’ nei tra un decollo e alla
quota di 35.000 piedi (di crocera)


Albert, I’m sorry I don’t speak Italian, but I believe your question is about the difference in thrust during take-off or cruise, right? During cruise it’s approximately 75% compared to take-off.
All the best, Miranda


Is Boeing 777 engine really bigger than A380 engine? Do you mean only civil aircraft enginges or it is also the bigges among military equipment as well?


Marcin, the A380 engine, GP7000, design is based on the Boeing 777 engine GE90, but is indeed slightly smaller than the GE90-115B. I’m not into military equipment, but usually a basic engine design is adjusted to its purpose, either military, civil or even industrial. In this blog we stick to our roots,which is civil aircraft engines.
All the best, Miranda


What causes compressor surge?
What’s flaming out and it’s cause?
How does the turbine extract power from the burnt fuel air mixture?
Explain the situation of BA flight 009 of 1982 (turbine )
Thank you


Hi Evans,
Very interesting questions, I guess you have a lot of knowledge of these matters
Your topics are well chosen, and will be addressed in next blogs so that we can bring our readers step by step, the operation of an aircraft engine. But I can already answer 1 question, What causes compressor surge?
A compressor surge is a disruption of the airflow through the aircraft engine,
if it happened to your car, it goes stuttering and gives poor response.
Keep an eye on our blog, there are nice themes where you may be interested in.
Kind regards,


Compressor stall is the disruption of the airflow like (air intake of the engine ) . Which cause an compressor surge . The engine begins to stutter and the continuous flow of the engine is disrupted . Eventually when you go to long in stall the airflow is disrupted to much and causes a flame out . Because the balance in the mixture of fuel and compressed air is disrupted and out of balance .

Sorry for the poor English hope I helped you on your way


The ignition fails and no more continious flow and than follows the flame out .

Forgot to add that to last sentence


Evans, thank you for your questions.
Please allow us a bit of time to respond to the it.


Do you maintain and overall the thrust reversers and what different types do you use cascade , pivoting door, etc


Dear David,
We maintain, repair and overhaul many engine parts, this specific question i will ask our Engine Part Department, and will let you know as soon as possible,
Kind regards, Jacky


Hi David,
Our colleagues at Air France Industry maintain, repair & overhaul trust reservers for different engine types.
Check out the website http://www.afiklmem.com, under capability search, you will find “component and / Engine part search”.
The cascade thrust reverser is commonly used on turbofan engines, what we use at KLM.
I hope this has answered your question.
Kind regards


I would like to know more about KLM’s pilots. Thanks!


Dear Liew,
Are you interested in becoming a pilot? If you need more information concerning training/ admission requirements
you can check “ KLM Flight Academy” at http://www.pilootworden.nl
Also a live chat available so you can ask questions directly.
Good luck!
Kind regards


What is the mean time between engine failure or what is the designed figure?


Dear Arie,
It is difficult to predict when an engine gets a failure, the performance of each engine is recorded and monitored 24/7 by a team of specialists. On the basis of the performance, the detection of any complaints. investigated and resolved.
Graphs and data are available for the team of specialists, but unfortunately not available for sharing.
Hope you’re not disappointed,
Kind regards


It changed my entire experience at work today. I confidently looked everyone in the eyes, and came to an enilhgtening conclusion! People have been trying to look into my eyes the entire time I’ve been working retail, and today felt like I finally got to really connect. Gone is the feeling of shame and guilt that comes with being a servant of sorts!


very informative and interesting.


Thank you Kay,
We feel therefore privileged to share this information with you, and hope to give you an idea what kind of things happened behind the scenes.
Kind regards


Hi, I would like to know why a trip from San Francisco to amestrdam takes an hour less time than going back to San Francisco.


Hi Rami,
The flight duration is indeed shorter, the reason is simply tailwind Airplanes uselly fly at an altitude of 10 to 12 kilometers and at these heights there are also several jet streams.
The most famous is the jet stream over the North Atlantic exactly the part where you fly through as you head towards America or the Caribbean. Very special, don’t you think? A helping hand from Mother Nature.
Best regards


Hi Rami, this is because of the jet-stream. High speed winds, normally blowing from west to east. So reducing the flying time from the USA to Europe.

Geoffrey Kennell

I notice that the inventor of the Jet engine was not mentioned. Frank Whittle was his name, and he couldn`t sell his marvelous engine to the British, who threw it out. The Germans however saw the potential, and promptly had a German fighter aircraft, jet propelled, in the air before Gt. Britain during WW2.


Thank you for your response. You might me interested to learn that in fact our Engine Shop facility carries the name of Frank Whittle.
All the best, Miranda

Mohan iyer

very interesting blog . Will follow . Best


Thank you Mohan.


Hi, can you please share with me the effect of sand pitting on engine’s blades and if that will be a valuable factor on engine’s life time and schedule maintenance?


Hi Aryam,
By raising this question, I’m going to assume that you probably know a lot more then 8 things about jet engines! Yes, sand- pitting is a factor affecting the engine blades, but may I recommend the more technical forums for this type of question? For example, Airnation.net or eng-tip.com.
Have a good day, Miranda

Jan Reijnders

I have an another question: why are aeroplanes disigned with those small windows. In the cockpit the windows are greater. Now only the passenger at the window can see what is happening outside the plane and down below.
Ik heb een andere vraag: waarom zijn vliegtuigen uitgerust met kleine ramen. In de cockpit zijn de ramen toch groter. Nu kan alleen de passagier die aan het raam zit, naar buiten kijken.


Dear Jan,
The pilot in the cockpit has most certainly the best view, has largely to do with safety and regulations. The design of an airplane will determine the number of windows and the size of these, as an example the new B787 Dreamliner has got windows twice as large as that of a B747. The future is promising, the design is becoming more transparant and futuristic and just a matter of time that all passengers can enjoy the view. But don’t be disappointed, on a KLM flight you have the option to choose your own seat, big chance you have a seat at the window!
Kind regards, Jacky



Lolita M. Balboa

Very interesting and really educational blog. Thanks.

jagath Rupasiri

This is really an interesting blog.Anybody who reads this blog can have a good general knowledge about jet engines.



Dear Jagath,
Thank you so much for this great compliment, our goal is to share our knowledge, and what`s so fascinating to aircraft engines. The following topics in our next blog`s will surely interest you.
Keep in touch!
Kind regards,


hi can You tell me what is the Flow rate of air per cubic feet per minute does a jet engine use say on a 747


Dear Warren,
Unfortunately formulas are not my expertise, but I can tell you something more about airflows
Pretty amazing that the air sucked into the engine contributes to the enormous forward thrust.
In our world the bypass airflow of an engine is much more interesting & important.
As an example the big one GE90 (Boeing 777) a high bypass turbofan two-shaft engine with a bypass ratio of 9:1.
And it goes like this: the sucked air into the engine is divided into two airflows,
1) Primary airflow goes to the core of the engine, the exhaust gas makes approx 17% of the forward trust
2) Secundary airflow (bypass airflow) goes around the core (bypasses), makes approx 83% of the forward thrust
Bypass ratio 9 to 1 means that 9 times more secundary air (bypass airflow) goes through the engine than primary air.
For engine type CF6-80 C2 ( Boeing 747) the bypass ratio is 5.15: to 1, means 5.15 times more ….. than ……
Sorry, no answer on your question, but hopefully you enjoyed reading this interesting fact!
Kind regards,


Hi Warren
A jet engine from a boeing 747 is by KLM a GE cf680c2 b1f for the pax and a b5f for a cargo plane. Your question for the airflow is at take off approx 35000 cubic feet per


Hi Warren
A jet engine from a boeing 747 is by KLM a GE cf680c2 b1f for the pax and a b5f for a cargo plane. Your question for the airflow is at take off approx 35000 cubic feet per second, when the plane is in flight its depending from different circumstances suchs as temprature, plane weight and airspeed, the engine thrust rating. I hope this a satisfactory answer for you


Aren’t there some jet engines used on airliners that are just about the same as those used at electric power plants, just missing the bypass fan and run from natural gas?


Kiitos, kaksi ekaa olivat outoja aiehiivruja/kirjoitusviroeptä. Mutta eikö KPRF osallistunut 10. päivän mielenosoituksiin, mielestäni yleisössä näkyi aika paljon niiden lippuja? (saattoi kyllä olla ihan vaan Neuvostoliitonkin lippu).


Hi Jeffrey, sorry for the late response on your question on our blog. In the mean time we posted a few other blogs and missed out on this question. You are right. GE’s Industrial Gasturbine LM2500 has the same coredesign as the GE Aviation engine CF6-80C2. Kind regards, Miranda

Neil Collins

Im thinking of buying a 1990 Challenger jet 601-3A its got landings 1986 and hours on engines 3994.


Hi, thanks for the article…
How much force does it take to get a fully loaded idle 777 rolling for a taxi?
Given that each GR-90 115 engine can push out 115,000 lbs of thrust (110,000 hp) – I’m interested to know how much force is required to get the big bird moving?

Thank you.


Hi, Ian
To move the big bird you definitely need a lot of power!
Each GE90 engine develops approximately 4000 pounds of thrust at idle, depending on the weight of the aircraft and the conditions of the surface, with both engines running slightly above idle the aircraft will start moving. We call this break away thrust. I hope this has answered your question.
Thanks for reading our article, and have a nice day!
Kind regards

Daniele Tatti

Thanks for this interesting blog.
I would like to ask an apparently strange question.
Is it possible that in very expeptional circumstances a jet engine might be replaced with a different one? With ‘different one’ I mean a different version of the same engine model, perhaps with just little visual or technical differences.

Thank you,



Hi Daniel, not a strange question at all. In fact it happens often that we replace the engine with a spare engine. For example if the original engine is due for maintenance. However they are always from the exact same model and type. So besides another Engine Serial Number, which is not visible from the outside, nobody would notice. Does this address your question?
Kind regards, Miranda


Hi, please if I may ask, last time I was flying on KLM, I was very near the front, so I could see inside the engine of the 777. I noticed that when the engines were powering up massively for takeoff, there was a thick liquid which sprayed out of the engine, as if the engine was spitting out something. Do you know anything about this liquid? and is this regular, or unusual?


Hi Rick,
Although it is difficult to explain from your message what you actually observed, it looks very similar to a phenomenon we call inlet condensation.
This is a very common phenomenon during the take off phase when the engine sucks a huge amounts of air, which under certain atmospheric conditions partially condensates in the inlet of the engine and forms a white “cloud” of air in the engine inlet. A normal behavior of nature!
Kind regards,

Marjan Radanovič

what is the procedure to sell used airplane engine, and who are the main buyers?

Chris Whitelaw

Given the efficiency of modern engines, suppose a 777 was in its longest range configuration and minus passengers and luggage. Could it theoretically fly from, say, Gatwick to Sydney non stop? (Say, as a positioning flight?).

Rob droog

Point 2 is incorrect, biggest ENGINE is RR XWB ENGINE. Powering THE AB350


Hi Rob, although the XWB is impressive as well in our opinion the GE90 is bigger. Lets agree to disagree?
Respectfully, Miranda


Leuk om jou te volgen via Twitter. Ik kon daar alleen maar sms'en naar mijn regtneiosen waar ieder uithing en waar en wanneer we elkaar zouden treffen op Central Square.Ik was er dus zaterdag en kon met enige moeite deze plaatjes schieten, toont meteen mijn dagroute. Het was erg druk, waardoor ik helaas Eric Vloeimans moest missen. waarom ze hem niet in de Maas of Nile hebben gezet is me een raadsel :-)Nu ook nog lekker aan het luisteren?

Rene Fivet

” Grease Monkeys ” ?? Echt KLM ? ( zie fact 1 in de blog ) . We vechten al jaren tegen deze denigrerende omschrijving van luchtvaart technici. Ik vind het jammer dat de KLM meedoet in dit. Blijkt maar weer hoe er gedacht wordt binnen de KLM over hun technici.


Beste Rene, we vinden het erg jammer dat je het zo ervaart. Wij zijn er trots op om ons zelf tot de grease monkeys te rekenen. Het is dan ook zeker niet denegrerend bedoeld.
Collegiale groet, Jacky en Miranda

José Hernández

Who do you use pounds for measuring thrust? It is something that is traditionally outside the metric system? (E.g. Altitude measured in feet instead of meters)


Hi José, both US and metric system are used, it’s a matter choice and preference.
Kind regards, Jacky and Miranda



Another usefull source for all your questions regarding gas turbines :)


Thanks for the link Ferry!


What do you regard as the better engine for A380…GE or RR?


Hi Rocco, we’re sure the RR is a great Engine as well but our familymember Air France is pleased with the GE/PW GP7200 powering their A380 Fleet.
Kind regards Jacky and Miranda


Hi there, very informative and I’ll stay tuned for future note, however, I was wondering If you give me how much force can tolerate each engines during landing due to the reverse trust and If ground handler do any routine check for r.f. or not?


Hi Amir, not sure about the exact number but it is not maximum thrust used by the thrust reversers during landing. Can you explain what you mean with r.f. please?
Kind regards, Jacky and Miranda


Do you also ferry an engines to other locations, and if this happens do you store the engine in the cargo hold or hang it under the wing?


Hi Delano, it is possible and sometimes necessary to ferry an engine on wing, which is always done without passengers on board, but we prefer to ship it in the cargo hold.
Kind regards, Jacky and Miranda


I like to work……the KLM workshop.


Which is the best engine maker….GE or RR


That’s an opinion Kamarol and not for us to be the judge of that….but the majority of our fleet is powered by GE engines

Kent Chong

How many hours and cycles before an engine being retired for good ? Or keep flying it until its damage for good.


Hi Kent, some critical parts in the engine have a life limit, meaning that they have to be replaced mandatory after a number of cycles flown. Other less critical parts are being replaced on condition. In theory this could go on and on, if parts remain available. But usually there’s an economical drive to retire the complete engine after several decades.
Thank you for ready our blog, Jacky and Miranda


People always refer to kerosine as jet fuel, long ago in the fifties that was the case, nowadays it is jet A1 a mix of
high octane gasoline and kerosine. There is no jet engine now that will start with pure kerosine.


Thank you for sharing this information Dolf!
Jacky and Miranda


How do you transport a new engine to a distant airport to replace a “dirty” one?


Hi Ralph, we usually replace engines at our technical facility at Schiphol Airport, but if the engine has to be replaced at an outstation, the “new” engine is transported to that location in the cargo bay of one of our aircrafts.
Kind regards, Jacky and Miranda


Скажите, а у вас есть RSS поток в этом блоге’Читая только ваш блог, я Ђ‘ейсôÂÂвительно расслабляюсь и получаю удовольствие


Why do engines in Airbus planes sound like they’re almost shut off right after take off?


Hi Diego, I guess one could say that during take off the engine roars like a lion because of the power necessary for take off and that it sounds like a cat spinning after take off when less power is needed to take the aircraft to idle. However this would apply to all engine and aircraft types, not specifically to Airbus.
Kind regards, Jacky and Miranda

Glenn Hassell

I want a roundtrip in KLM garage to see how u gays working

Edward Kommers

How much air (cubic meter) gets sucked into a GE90-115B when at full throttle?
And is full throttle ever reached or does it take off at 80% for example. I can imagine that cruising would require only a small percentage of the full potential of the engine?


Hi Edward,

In take off that would be about 3000lb/per sec. And indeed it’s 80% MPA

Kind regards, Jacky and Miranda

Ali Jabbar

Very interesting info !!!
Thank you Klm !
Ali Jabbar


You’re welcome Ali!


Hello KLM why does KLM operate mainly us manufactured airplanes and not europian (Airbus) ?
Your fleet only has limited amount of Airbuses incomparison with Boeing.
Recently your fleet has been expanded with the 777 instead of the A350?


Hello Miko,
There’s to Some extent an economical and logistic advantage in having a certain alignment in your fleet, but we are very happy with the A330 as well. Together with our familymember Air France we believe we have a good mix between Airbus and Boeing.
Kind regards Jacky and Miranda

Wan Mohd Kamil Bin Wan Kadir

Just wondering how the jet engines start-up? Either from ground starts which means from an auxillary power or the aircraft itself equipped with their own starter for each jet engines?.




Hi WMK, you may find the answer in this blog https://blog.klm.com/does-an-aircraft-have-a-key-jesseyknows/
Kind regards Jacky and Miranda


Nicely done blog. Keep it up!

Willem Gouws

I really enjoy this blog!
Another question from my side: How long does it take to replace an APU on a wide body and narrow body aircraft?


Hi Willem, happy to learn that you enjoy the blog! As for your question, the replacement of an APU takes about 4-6 hours, and there’s no real difference between in time on the WB and NB.
All the best, Jacky and Miranda

Julius Slamet

If one engine malfunction during takeoff or landing, it’s the aircraft still can do landing and take off??


Hi Julius, we are happy to inform you that an aircraft can indeed continue with a safe take off and landing with one engine. Although we prefer to do it with all engines working :-)

Dawodu O. A.

I amnvery impressed with the information so far gathered. Thanks.

Jacky van Damme

Glad you`re impressed, Miranda and I are privileged and find it very nice to share all these facts & information with you.
Best regards, Jacky


I’m in contact with a family member of the former airline company Okada Air of which still has the jets sitting in the airport. We would like to get an idea of how much the engines of the 2 747s are worth. A Boeing 747-128 and a Boeing 747-146


Hi there, why there’s different tail wind limitations on take off and landing across differente engines types. For instances CF-6 as a 10kts while PW4000 as 15 for the same a/c model.
Btw fantastic blog.
Best regards.


I may have missed it in all of the comments, but which engine is that a close up of? (The close-up photo of the side of the engine) Thanks!


Its a GE CF6 Cory.
Great picture isn’t?


Very interesting.

But I’d like to ask.
HOW much oil does a typical 747 or A320 engine take ??


Please advise how the jet engine will run at the height of 35000 feet where there is no oxygen, how it will run without oxygen?


I once heard that a jet plane uses about 25 % of total available power for a normal takeoff. I don’ know if it was two or four engine. Is that true?


Hi Even, during take off its max 80% of available power per engine.. 25% would be possible during cruise..
Kind regards, Miranda

Alejandro Rivas L.

Great job and I love it. I was flight attendant in Mexicana airline and I know about it. Also I’m private pilot. Thanks


Do you still operate rolls Royce engines as well are they not supposed to be the best


Hi John, KLM doesn’t operate jetengines from RR, but we do hear good things about RR WXB jetengine.
Kind regards, Miranda


How many parts on average a Jet Engine consists of.? And how heavy is a Jet Engine on average ?

MIGUEL Huerta Barragan

Interesante información. KLM es , para mi, la aereolinea mas confiable en el mundo. Felicitaciones y cobtinyar así.

Cesar Lagreca

Its very interesting this subjects, and demands a lot of people to care this things. Tks for the informations..send more.
Cesar Lagreca


Does K.L.M get discount on aircrafts when you buy in bulk


It says miinor maintainance every 200-400 cycles (or flights) . . . That can’t be right ? If it is, I’m never going to get on one ever again . . . EVER !!! ☠️☠️☠️


I’ll jet your right!!


Hi, do these engines use engine oil? If yes, how many litres required?

Manuel Martin

Miranda thank you for the hard work answering all the questions I learned a lot today. All the best to KLM family

Antonis Petrou

Thanks KLM for sharing these info with us. It’s good to know some minor things about jet engines. But it’s only a needle in a hay stack. Appreciate every detail KLM shared with us. Oh… my EVO is faster than your planes. 0-100 3,5sec, and 1/4 11sec… :) :) :)


Does airplanes fly with mechanicians or technicians? Can they do something on failed engine in mid air?

Hans de Beer

Ik reed enige tijd terug op Schiphol Oost -het beveilgde deel bij de hangars- .Vóór mij reed een trekker met een motor als sleep op de aanhanger. Mijn indruk was dat de aanhanger mogelijk door het gewicht nogal slingerde, maar wat ik helemaal vreemd vondt was dat er op de aanhanger geen enkele verlichting aanwezig was!! Is dit de normale procedure?De combinatie reed op de openbare weg…..


Beste Hans,
Zonder de exacte situatie en het tijdstip te kennen, nee, het is geen normale procedure dat de trekkers zonder verlichting rijden. Dank voor je opmerking. Alle transportbewegingen van een vliegtuigmotor zijn luchtgeveerd ivm de lagers.
Daardoor kan het er al snel slingerend uit zien.
Groet, Miranda

hai king

how does one join klm engineering ? a fresh grad i might add


These motors also power altenators to generate electricity in the most isolated regions in the world, an example is the spitfire motor famous as in and out power house.


That is so interesting! What does it mean if I like me a big, bad red one dayand say, that de-lish Muscat another? I like to think of myself as an equal opeyrtunitodrinkpr, but maybe I have wacky buds! Thanks for sharing, Betty, I feel a little more wine-smart every time I read! Cheers!

Robert H.V. Schurink

Hi, thank you for your very good explainatory info. But I am sorry to have to write you that the part pertaining the costs of the engines is not quite correct. The aircraft (financially wise as well) can be split apart. In the way aircraft are financed there are lease contracts /separate ownerships regarding the “full body” and the engines of the plain. So it would be possible to mention the costs of your engines, but of course I understand you have no wish or interest to reveal the amounts….

Simon Munguu

Hi everyone. I would like to know if anyone has specifications and dimensions of GEnx or Trent 1000 combustors used in B787

kamlesh vachhani

Dear sir.

This is kamlesh from india, Gujarat. I’m an mechanical engineer and I am always interested for aerospace industry and its technology.

My point is what are the best methods of maintainance of jet engine. I mean ultra sonic or any other methods?

Marvin Katende


My inquiry is about the CFM56-5A engine employed on the A320 aircrafts.

What are its take-off and cruise;
1. Air and fuel mass flow rates?
2. Take-off and cruise thrust?

Thank you!

Ahmad Ali

What is the normal acceleration of an aircraft during takeoff?




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Un mal uso de los préstamos rápidos ( de cualquier
otro producto financiero) puede ocasionarnos algunos inconvenientes que perjudiquen seriamente
nuestra economía.

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You really saved my skin with this inofmration. Thanks!

Olowofoyekun Oyewale

What happens if an airplane on motion about 35000ft from ground level got hit seriously by lightning or thunder ??

Clayton J Morin

Airliner engines use a kerosene based fuel called “Jet A” which is in terms of pumped fuel, is the premium of diesel fuel and CAN be used in Diesel engines…


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Powerjet Parts

These engines likewise control alternators to produce power in the most secluded districts on the planet, an illustration is the firecracker engine popular as in and out power house.Thanks KLM for imparting this data to us. It’s great to know some minor things about fly motors. Welcome everything about imparted to us. Gracious… my EVO is speedier than your planes. Visit my site-

tech adviser

This blog looks just like my old one I have been looking everywhere for this! This really answered my problem. Exceptionally well written! I would like to say cool blog!


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I want to know that in full overhaul of CFM56 engine types, which parts should be replaced and how much we can price for the full overhaul. i need so urgently this data. if any one could help me please?


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Hello KLM
I really like flying GIG-AMS-GIG with you. In special when we have 789s. Can you tell me how affected you are by EASA Emergency Airworthyness Directive AD No.: 2017-0253-E concerning the TRENT 1000 sulfidation issue?
Many thanks! Best regards


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How big is the budget (%) of an airline for maintenance? And maybe specifically engine maintenance? That seems to be one reason for discontinuation of 747s (4-engines)


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Kam Leung

I thought each manufacturer is supposed for engine maintenance worldwide? I once flew with a Rolls Royce engineer. He says his job is to inspect their engines worldwide, and was horrified to find some places which saw off the struts to mount their engines. How can KLM certify their technicians for all kinds and vintages of engine manufacturers?
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