It all comes down to total cost per flight hour, abd yes that is computed over the life of the plane so airframe cost and engine overhaul costs are part of the equation.
Flight hour costs are fuel and checks and tests routinely done on an aircraft after it has flown as an average.
If you land the plane and on inspection you find that a metal washer has been ingested into the engine and several blades in one engine are destroyed and the entire engine needs to be replaced how does that fit in to the flight cost per hour for the aircraft... you are not going to get FOD on every flight, but the price of a new engine is going to sharply increase operational costs.
Flight cost per hour basically means all the checks and tests made to the aircraft every time it flys... it means unscrewing and removing some panels to access electronics and replacing minor components and testing larger components to find problems before they become serious... like temperature increases in parts of the engine might need the engine to be removed and inspected, but otherwise not something you would normally do.
Modern computer systems can do diagnostics and can be fitted with sensors throughout the aircraft to indicate a problem before something bursts into flames or falls off.
The MiG-21 was relatively cheap because its components were cheap and replacing a lot of parts wasn't expensive or very time consuming.
The original support routine for the MiG-29 was wasteful of parts, but for a war machine it meant short periods of maintenance and down time, and more time flying and doing its job. You would end up throwing out parts before they needed to be thrown out but in combat being able to last 5,000 hours for an engine or airframe is meaningless.
The F-35s enormous price per flying hour comes from its special coating... if its amazing computer system indicated a problem it would locate the electronic component that needed attention or replacement... on the much cheaper F-16 or MiG-29 you get a screwdriver and take off the panel and check the item... if it is faulty you replace it and screw the panel back on and then test it via the computer network... if everything is OK you are good to go.
With the F-35 you get the sander out and sand down the edge of the panel you need to open... clean around the screws, which you then unscrew to open the panel... the screws and joins of the panel will have tape over them... sand down to the tape and then peel off the tape to reveal the panel edge and screw heads. Unscrew and remove the panel and find the problem... solve it and then replace the panel put fresh tape around the panel edge and over the screws that are now suitably tightened.... and then spray the RAM material over the panel and the panel joins and screws making sure to cover the tape and every area you sanded off to a nice even finish and then wait 48 hours for the RAM material to cure properly and then you can fly the plane again... little wonder it is so expensive... all the more so because sometimes the funny signals and problems from one module is because something else has failed and is giving it the wrong information so it isn't working because something else is broken... which might be under a different panel....
Flight hours cost does not include airframe life or engine life or the cost of serious items like replacing radar elements or avionics components... it is the cost of normal maintenance to keep the aircraft running including items that wear out with normal use at the rate they are replaced.
Therefore replacement on schedule means replacing parts that might not need replacing yet so it can be more expensive than inspections, but inspections take more time, but allow parts to be used more efficiently as they can be replaced when they need to be replaced.
It can also mean faults where something is getting excessively worn because there is a problem can be detected and corrected.
Replacement on a schedule is great for war... fuel it arm it and fly it.
Inspections means check it and then fuel it and arm it and fly it.
Yes most airframes can have service extended.
So for instance there were amazing claims of airframe hours for the F-35... 6K or 8K flight hours, but in practise they were getting 2K because of problems.... the flight costs didn't jump at all at that revelation and they should have quadrupled...
Equally if airframe life counts then life extensions should make the operational flight costs become cheaper... does that happen retroactively?
A plane that cost 8K dollars per hour to maintain gets a 2K hour airframe life extension... does that mean it only cost 6K dollars per hour previously?
Or does it mean for the extra 2K hours the price double drops because spread over an extra 2K hours the hourly rate goes even lower so it becomes 4K per hour to operate...
Sometimes with deep inspections, and sometimes with some parts replacements.
Which is going to be different for each individual aircraft... what happens if one pilot pulls 12g in an emergency during a flight... will that aircraft have the same cost per flight hour...
I wonder how many Tejas a mig 35 can take on and defeat. ... and considering the Tejas engines are from GE, the MIG is proabably cheaper.
A better question would be with American engines and needing US dollars to buy parts and support will the Tejas be any cheaper to operate than a MiG-35?
Quick question, which variants of the MIG-29 have FBW?
All the new models of course (29M, 29KR, 35).
For all the hype about FBW the amusing thing is that high offboresight AAMs and helmet mounted sights turned out to be more important during tests in Germany in the 1990s... the old MiG-29B model beat all the western fighters including the super dooper F-16 with its FBW system.
But in general I don't agree a much more expensive fighter is "cheaper" because it needs less overhauling.
A general rule of thumb for most fighters is that the purchase price is normally similar to the life cost of the fighter... so 120 million for an F-35 will probably cost another 120m over its lifespan in operational costs... I suspect the cost of the Rafale for India was because they built a lot of its life span costs into the purchase price.
That is the logical strategy when your pieces are cheap compared to doing complex testing of the plane, with modern systems that is not the case anymore, but that defeats the purpose of having a cheap plane.
One of the improvements of the SMT upgrade was computerising of the systems so internal diagnostics and internal sensors could be used to detect problems early before they led to catastrophic failures. It made problem solving and repair simpler and easier and cheaper using smarter components.
You can have a simple computer that does all the things you need it to do without needing some bleeding edge money pit... I have a cheap $70 dollar tablet with USB ports and WiFi to watch movies in bed at night if I want.
A 17 cm screen 30cm from my face is effectively a 3m screen on the other side of my room... but cheaper to buy and uses less power.