Are these increases the result of the open skies policies over the winter season
In some cases yes, but in others no.
Northwest's service for example doesn't require the open-skies policy to operate - they have the flexibility under the India-US bilateral to add service anytime they want, but they chose to add it from November 1 to February 28 since that represents the peak travel period.
El Al's flights will be a permanent schedule addition (that has been in the works for over a year now but was held up due to shortage of 767s), and it appears so far that Royal Jordanian's new service will also be permanent.
Air France has realigned their capacity based on some minor modifications to the India-France bilateral earlier this year, so their schedule change is also permanent (they have also upgraded DEL permanently to a 744 and discontinued codeshare on Delta metal to BOM).
Alitalia has always operated daily winter and 6x summer to India, a quirk of theirs that they run to many destinations.
Air Mauritius is the only one so far that appears to be only a seasonal addition due to the open skies period, but I'm not familiar with the India-Mauritius bilateral so I don't know the flexibility they may have in the first place.
What are the exact mechanisms of this limited open skies policy? Does it work for all Indian airports or are there places that are excluded?
Basically it allows any airlines already authorized to operate to a specific gateway in India permission to operate as much capacity as it wants on that route during the designated open skies period without regard to bilaterally negotiated limits on capacity.
All additional services must be subject to the same commercial conditions as the existing services (eg. if codesharing with AI
/IC on the existing flights must also codeshare on the additional flights).
It does not permit carriers not already authorized to serve India to commence service in the market and does not permit carriers to serve new gateways solely for the duration of this period.
As for NW, didn't they fly in a B744 at a certain point in time? Any reason for the capacity reduction to DC10 but frequency increase with 2 aircraft operating?
ran a 744 on the India route until end-February 2003. I actually flew on their last 744 into Mumbai around the 26th or so. At that time it was downgraded to a D10 because the 744s were needed to cover CRAF callups due to Iraq mobilisation. Following that, the Iraq war, SARS and the accelerated disposal of 742s meant that there simply wasn't any additional 744 lift to spare for BOM operations. Since the A330 with PW
engines is not yet route certified for terrain clearance on parts of the BOM route, the D10 is the only option if they don't want to incur the costs and hassles of certification and/or proving flights.
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