Indigo business model threatened by PW1100G?

Yesterday I read that Indigo sees their business model threatened by the engines of their A320neo – because of  the longer start-up times of the PW1100G (dependent on how long the engine was out after shutdown) the aircraft has to wait up to 2 min. longer with their engines at idle before the aircraft can begin to roll and taxi for takeoff.

Now let’s have a look if there is anything in this claim by looking at how Indigo actually operates their aircraft:

According to flightradar24 the 3rd A320neo (VT-ITA) flew on May 2nd from Delhi to Nagpur. The aircraft landed perfectly on time at 3:40am (UTC). It took off again 52 minutes later, 7 minutes later than scheduled but early enough to arrive back in Delhi 4 min. ahead of the scheduled arrival at 5:56am.

The 2nd leg of the day went to Bangalore with a scheduled departure at 7:30am (actual departure time 7:55am). The aircraft arrived Bangalore 3 min. ahead of schedule at 10:17am. Scheduled departure back to Delhi was at 11:15am, which was missed by 9 min. Arrival in Delhi then was 5 min. ahead of schedule at 13:50am.

So we can see no delays stemming from the start-up times. The 2 min. longer start-up time is an the maximum, which only occurs when the engine was off for about 2.5 hours. But turn-around times for the two legs was below one hour, so the extra start-up time should be something between 1 and 2 minutes.

Now let’s look at the extra costs: at idle, the engines would burn about 750lbs/hour each. For the maximum extra time (2 minutes) this would be 2 x 750lbs/hour*(2/60) = 50 lbs, which is about 7.5gallons of fuel. The price of fuel according to Indian Oil (https://www.iocl.com/products/aviationturbinefuel.aspx) is at $457/tonne. The 50lbs (22.7kg) therefore would lead to extra costs of roughly $10. Compare this to roughly 9000lbs of fuel burned for a 800nm mission (Delhi-Bangalore is 909nm Great Circle Distance), leading to fuel costs of $1877. So the maximum fuel burn impact of the extra start-up time is 0.5% of the mission fuel burn.

I understand that the daily utilization of the Indigo A320neo is limited at the moment – although in the last week they were sometimes flying three legs a day instead of two with daily flying times up to 12hrs. But that is probably due to the fact that the A320neo are only flying from and to Delhi as the customer field representative from P&W is probably located there and – similar to Lufthansa at Frankfurt – technical capabilities from Indigo are concentrated at Delhi airport. So we have to see how the aircraft behave once utilization changes to more (and shorter) flights a day.

But for now I cannot see how the extra start-up time threatens Indigo’s business model – not in terms of aircraft neither in costs.

So my guess is that Indigo uses this claim to negotiate more and higher compensations or lower prices for the next engines and FMP rates from P&W.

One has to say that P&W did an awful bad job in communicating the start-up topic. Instead of openly talking about it their customers were the first reporting about it. and of course the question is why such a fundamental physics-based effect which occurs in each and every engine was so greatly ignored by P&W. Obviously it was not discovered as an issue before late last year, why it now takes half a year after EIS to introduce the fix into the production line.

Let’s see what Qatar and others have to say after getting their first engines with the fix…

Another thing just caught my eyes. According to a story in Flightglobal (sorry, I have no link) the dispatch reliability of the Indigo A320neo's was 99.02% between March 18 and April 24. When I look at the data I compiled from Flightradar24, the three A320neo that were in the fleet during these days did 82 flights. Now, if there was just one flight that was cancelled due to the engines, the dispatch reliability would have been 98.78% - so how can Indigo mathematically get to 99.02%?


  1. You are right AeroT. But airlines are always looking for ways to get a better deal when they can. Also, they figure that if Qatar can get away with some free media coverage(when U Turn Al start bit.... about anything) other can probably try as well.

    1. If an engine misses sfc by 0.5%, that's something to be discussed too. Do it all fleet over a longer period and we get into millions.