Delta MD88/MD90/737-800/A320 Utilization Question

DeltaRules · Wed Dec 10, 2014 10:23 pm

As a somewhat frequent passenger on CMH-ATL, I've noticed the route typically sees five different types (73G, 738, M88 M90, 320), four of which are very similar in terms of capacity (M88: 149, 320: 150, M90/738: 160). On a recent itinerary change made due to a family illness, the 12:25pm flight went from a 738 (originally booked) to an MD-90 (same flight, five days later). Same number of seats, two different airplanes.

Similarly, on ATL-DAB, you'll often see one or both of the Mad Dogs among the 4-5 daily flights, with a token 757 thrown in, but the 738 and 320 tend to be less common.

Simply put, how does DL typically determine how they'll use these four on a short-to-medium haul flights? I know the M90 has 11 extra seats, a little extra range, and the power for more hot-and-high operations as compared to the M88, for example, but is there any science behind the interchangeability of the four on routes such as these?

avi8 · Wed Dec 10, 2014 10:28 pm

I do not know the answer to your question. However on a side note, I do have to admit that it never ceases to amaze me how Delta rotates its aircraft around and how they change equipment throughout their network. They must have some very savvy people working on it 24/7

flyorski · Wed Dec 10, 2014 11:37 pm

Based on my limited experience DL appears to keep the A320s and A319s on rotations that will bring them through SLC throughout rotations. The MD90s seem to rotate in ways that bring them through MSP. As for the others, the 737-800s appear to rotate pretty equally through all hubs and the MD88s tend to stick on routes that allow them to rotate via ATL down the road.

Likely someone with a lot more knowledge can correct me or further explain

MIflyer12 · Wed Dec 10, 2014 11:49 pm

I expect the answer is deep, dark ops management/revenue management voodoo. Things like pilot availability in a category, FAR 117 compliance, pilot contract amendments (min pay changing trip construction), hot/high in typical seasonal temps, aircraft upgrade schedules, average fares for the incremental seats and all the rest would figure into the plans.

N501US · Thu Dec 11, 2014 2:09 am

I'm all for ad hoc efficiency.....I just wish their software would automatically change those of us in exit row seats to something other than a middle seat in the back of the bus when they do change equipment. Nothing like making your reservation in an exit row (concious choice over EC as a Platinum) and ending up with something not so good.

N908AW · Thu Dec 11, 2014 2:34 am

Quoting DeltaRules (Thread starter):
Simply put, how does DL typically determine how they'll use these four on a short-to-medium haul flights? I know the M90 has 11 extra seats, a little extra range, and the power for more hot-and-high operations as compared to the M88, for example, but is there any science behind the interchangeability of the four on routes such as these?

Quoting flyorski (Reply 2):
Based on my limited experience DL appears to keep the A320s and A319s on rotations that will bring them through SLC throughout rotations. The MD90s seem to rotate in ways that bring them through MSP. As for the others, the 737-800s appear to rotate pretty equally through all hubs and the MD88s tend to stick on routes that allow them to rotate via ATL down the road.

I think the answer is inexact, so you can come up with examples of routes that don't meet the criteria I describe for a specific aircraft. There are definitely exceptions to each subfleet's typical mission.

One of the first things the combined DL did after the merger was move the bulk of the MD90 work to MSP and ATL and most of the A319/320 fleet went from MSP to...everywhere else. I don't think it's as separate a fleet as people thought, and they tend to move around a lot. The basic reasoning was that the Airbuses had better range that was not being utilized out of MSP. The MD90s struggled to go east from SLC, whereas they can hit pretty much anything from MSP. Meanwhile the 320 and (more so) the 319 can hit just about everything from SLC.

DL seems to have quite a few fleets/subfleets that they have put in the category of basic, no BS mainline that covers their bread and butter routes, which are short, erse set of routes and it's sometimes unclear if they view the 'buses in the same light as they do the MDs. They appear on many of the same routes, but at the same time I would think the average stage length of the 319/320 is probably slightly higher compared to the MD88/90 fleets.

The 73H, 739 and some of the many different 757 subfleets are usually found on more premium routes. Routes to LAS, for instance, are more often 73H/757 than MD90 even though as you've pointed out they have the same amount of seats. The 73Hs (with PTVs) seem to be viewed as more of a premium aircraft than the MD90 and thus they usually are often found on competitive, high stakes routes.

Like I said, I think these theories are not exact. They might only responsible for about 60-65% of actual aircraft usage. The rest is just seemingly random flights around the system before returning to their usual maintenance base.

International fleet usage is pretty straightforward comparatively speaking.

B4REAL · Thu Dec 11, 2014 2:40 am

I too fly CMH-ATL quite a bit (6-12x monthly, mostly for connections). Sometimes I see them drop in the 717, though it's been awhile.

I think really they (and other airlines) have advanced system cap planning that puts the right # of seats, staff and schedules in the right place for the right days. It's complicated, yet that simple.

PSU.DTW.SCE · Thu Dec 11, 2014 5:07 am

There is a very sophisticated system that is used to allocate the fleet to specific routes.
It is based on operations research and a system of various constraints.

There are base-line or "rough-cut" / default schedules out there, which are the advanced schedules beyond 90 days.
There are default aircraft types associated with the routes. Marketing and operations have input into assigning specific aircraft types to a given city, route, or flight for marketing or operational reasons.

Within 90 days inputs such as available aircraft hours, crew hours, maintenance requirements, advanced bookings (less than 5-10% of the aircraft are known and they move from a default/rough-cut schedule to a more fixed schedule. Typically within 90 days the route frequency is defined. At 60 days they typically set aircraft type and operating carrier. There are certain dependencies, primarily for labor and fleet planning that require this to be set in advanced.

There are certain markets/profiles for each type. However on shorter routes, its more a function of the number of seats and what aircraft are available at that time.

Delta MD88/MD90/737-800/A320 Utilization Question

Delta MD88/MD90/737-800/A320 Utilization Question

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RE: Delta MD88/MD90/737-800/A320 Utilization Question

RE: Delta MD88/MD90/737-800/A320 Utilization Question

RE: Delta MD88/MD90/737-800/A320 Utilization Question

RE: Delta MD88/MD90/737-800/A320 Utilization Question

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RE: Delta MD88/MD90/737-800/A320 Utilization Question

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