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What's The Real Importance Of Commonality?  
User currently offlineLHMark From United States of America, joined Jan 2000, 7255 posts, RR: 42
Posted (13 years 7 months 3 weeks 9 hours ago) and read 2828 times:

Everyone on this forum talks about fleet commonality as if it were the end-all be-all brass ring that every airline is trying to reach. I understand the benefits of commonality, on the surface, but can anyone actually share the impact that commonality may have on the bottom line? What about airlines that don't seem to care about commonality? Are there any fiscal advantages to fleet diversity? Discuss.


"Sympathy is something that shouldn't be bestowed on the Yankees. Apparently it angers them." - Bob Feller
16 replies: All unread, jump to last
User currently offlineLHMark From United States of America, joined Jan 2000, 7255 posts, RR: 42
Reply 1, posted (13 years 7 months 3 weeks 6 hours ago) and read 2792 times:

Come on! Everybody always trots out the ideat that all airlines want essentially three types in their fleet! Someone has to have some knowledge on the subject!

"Sympathy is something that shouldn't be bestowed on the Yankees. Apparently it angers them." - Bob Feller
User currently offlineScottb From United States of America, joined Jul 2000, 7516 posts, RR: 31
Reply 2, posted (13 years 7 months 3 weeks 5 hours ago) and read 2785 times:

Commonality gives you:

* Lower pilot training costs. Pilots change between equipment types less frequently, and fewer training events happen each time a pilot upgrades or downgrades. This translates into a need for fewer simulators and instructors; also remember that a pilot still gets paid while in training, even though he's not generating any revenue for the company.
* Lower maintenance costs. The company requires fewer spare parts to be kept on hand in each location (since you'll need spares for each fleet type). The mechanics are also more efficient due to greater familiarity with the equipment.
* Lower flight attendant training costs. Again, fewer things which work differently on one type of airliner versus another.
* Greater flexibility in irregular operations (especially true for WN). Since they only fly one type of plane, it's far easier to substitute another 737 if one goes off-line for unscheduled maintenance.
* Somewhat improved negotiating power with airframe manufacturers when placing large orders, although this is somewhat diminished when placing follow-on orders.

I'm sure that's not exhaustive but it's a start.

User currently offlineTrickijedi From United States of America, joined May 2001, 3266 posts, RR: 4
Reply 3, posted (13 years 7 months 3 weeks 4 hours ago) and read 2768 times:

I think Scottb pretty much summed it up. In this day and age, especially with increased competition and heated union negotiations, costs need to be kept at a minimum.

Its better to be on the ground wishing you were in the air than be in the air wishing you were on the ground. Fly safe!
User currently offlineLHMark From United States of America, joined Jan 2000, 7255 posts, RR: 42
Reply 4, posted (13 years 7 months 3 weeks 2 hours ago) and read 2735 times:

So what about HP, AF, and other companies for whom commonality doesn't seem to be an overwhelming issue? What is their economic reality that they don't sweat it as much?

"Sympathy is something that shouldn't be bestowed on the Yankees. Apparently it angers them." - Bob Feller
User currently offlineStrickerje From United States of America, joined Feb 2001, 723 posts, RR: 1
Reply 5, posted (13 years 7 months 3 weeks 1 hour ago) and read 2727 times:

Well my guess would be that, even though HP operates Boeings and Airbuses, they operate enough of each to be able to maintain them efficiently. Also, they operate A319/320's and B757's, between which there is a substantial size difference, so it isn't as though they're buying 2 types of airplanes that are comparable where only 1 would do.
Now as for AF, with its fleet of A310's, A32X's, A330's, A340's, B737's, B747's, B767's, and B777's, I would definately say that that's an example of excessive fleet variety. My explanation is... they're just nuts.  Smile

User currently offlineUal777contrail From , joined Dec 1969, posts, RR:
Reply 6, posted (13 years 7 months 3 weeks 1 hour ago) and read 2715 times:

But how successful is AF?
I really don't know much about AF, and I know HP isn't in the best shape.

ual 777 contrail

User currently offlineSjc>sfo From , joined Dec 1969, posts, RR:
Reply 7, posted (13 years 7 months 3 weeks ago) and read 2712 times:

NW doesn't seem to be in to the whole fleet commonality thing... what are we looking at here
727-200 (gone soon though)
along with Avros and Saabs with airlink
rumors are strong about the 777

They have fared pretty well, and they seem to do a great job of matching up route demand to aircraft.

User currently offlineTeva From France, joined Jan 2001, 1881 posts, RR: 15
Reply 8, posted (13 years 7 months 2 weeks 6 days 15 hours ago) and read 2676 times:

About AF,
As far as I know, AF has no more A310
A32x, A330 and A340 have a lot in common, reducing training cost for pilots
767 will not stay too long.
This reduces the types to only few families.
and if they need so ñany types of planes, it is due to their network

Ecoute les orgues, Elles jouent pour toi...C'est le requiem pour un con
User currently offlineN79969 From , joined Dec 1969, posts, RR:
Reply 9, posted (13 years 7 months 2 weeks 6 days 14 hours ago) and read 2661 times:

Air France had about the most complex fleet in the world. They are rationalizing though. The 767s are leaving and the 332 are taking their place. I think the fleet commonality has another interesting effect though.

I think it creates a new barrier to entry for any potential transport aircraft mfrs. If a new company wants to enter the market for civil aircraft, they will have a hard time competing with a single type on offer. It would be an orphan in the fleet. Any new entrant has to offer a family of aircraft or at least a model that can be shrunk or stretched without changing basic structures such as the wing.

For airlines, commonality increases the opportunity cost of switching between aircraft families. I think the cost is too low at this point to actually deter an airline from switching from A to B or vice-versa. However it is a relatively new factor in play on the cockpit side of things. I think it has been an issue on the maintenance side for a while though.

Overall commonality is a big plus of new-generation aircraft.

User currently offlineDesertJets From United States of America, joined Feb 2000, 7906 posts, RR: 14
Reply 10, posted (13 years 7 months 2 weeks 6 days 13 hours ago) and read 2653 times:

Commonality does have its limits, much of which are quite artificial.

Common cockpit between the FBW Airbus products is great for airlines that don't have strict seniority rules. So conceivably, a pilot could be certified in the A32X and A330 and fly both types in the same month. This however is not an advantage to carriers that operate under seniority systems. Which is basically all of the US carriers. But a family of aircraft, like the 737, 757/767, A32X can be of advantage. Essentially you have a choice of aircraft, with common type rating and largely similiar parts and mx schedules over a wide range of seating capacities.

So for an airline like Continental using the 737 as the standard domestic narrowbody they can acheive cost savings through pilot training, fleet scheduling and parts stores.

Ultimately commonality can help acheive an economy of scale. If you cannot operate any single one type in a large enough quanity, a fleet with some level of commonality can help acheive that economy of scale.

Stop drop and roll will not save you in hell. --- seen on a church marque in rural Virginia
User currently offlineScottb From United States of America, joined Jul 2000, 7516 posts, RR: 31
Reply 11, posted (13 years 7 months 2 weeks 6 days 5 hours ago) and read 2620 times:

Some of the reasons behind NWA's lack of commonality are historical (or temporary), though. The DC-9 and 727-200 are no longer manufactured, so they had to choose between the 737 family or the A320 family in order to replace planes that were ready for returement. The MD-80 was also a possibility (and they'd operated a few inherited from RC). The DC-10, 747-200, and 747-400 have different capacities. Replacing the aging DC-10's requires a new type in the fleet; they chose the A330 (probably in part due to their pre-existing order). They also added 757-300's for high-density domestic routes (and these fit in well with their fleet of 757-200's).

While commonality is an important way to reduce costs, airlines can't just ground large fleets overnight simply because they're not common with a new type coming online. But a significant portion of the 737NG's success owes to the commonality it shares with the older models of the 737 family -- there's a very clear upgrade path with a minimum of cost for the operator.

User currently offlineJetlanta From United States of America, joined Jul 2001, 3612 posts, RR: 35
Reply 12, posted (13 years 7 months 2 weeks 6 days 3 hours ago) and read 2603 times:


I usually don't chime in on this board but I've been kinda bugged about this line of thought myself.

All the reasons stated above are excellent reasons FOR fleet commonality. However, it is important to recognize that all of those benefits come down to one thing...COST SAVINGS.

The component that many posters miss when they analyze fleet decisions is capital expense. Just like buying anything, sometimes the best choice is LEAST EXPENSIVE one. The capital cost buying an aircraft is typically amatorized over 20-25 years. The lower the aircraft price, the lower the payment. Oftentimes the savings gained here can offset 20-25 years of expenses related to lack of commonality.

To use an example talked about on here before, say Airbus offers Delta a very good deal for A318s. It is entirely possible that Delta could save enough money on the aircraft purchase price that it would offset the additional expenses incurred by adding a new type.

Most well-managed airlines are very capable of developing financial models that project these costs out over the lifespan of the aircraft. If you see a well-run major carrier make this kind of decision, you can be assured that they have done their homework.

One last important point to consider. Airplanes are very expensive. Being dependent on one supplier reduces an airline's leverage. Often the primary manufacturer is simply unwilling to give its best customers as big a price break on future sales, simply because the manufacturer thinks it has the upper hand.

User currently offlineGeotrash From United States of America, joined Jun 2001, 326 posts, RR: 0
Reply 13, posted (13 years 7 months 2 weeks 5 days 22 hours ago) and read 2583 times:

One more significant cost benefit is tax savings. Every $50,000 laser gyro, or engine-driven generator must be depreciated as an asset over time, and taxes are paid on its value- even while it sits on the shelf. As such, it makes enormous fiscal sense to minimize the types of expensive parts an airline has to inventory. Like SWA, better to have to only stock one type of laser gyro, than five.


User currently offlineL-188 From United States of America, joined Jul 1999, 30408 posts, RR: 57
Reply 14, posted (13 years 7 months 2 weeks 5 days 22 hours ago) and read 2579 times:

Another thing to consider too is that a lot of the pilot commonality benifits are eliminated by the union rules at a particular shop. This is especially true in the US where you, for example would have to substitute an A320 pilot with another A320 pilot, They couldn't use an A340 pilot because of senority and union issues.

User currently offlineCrazyboi From Canada, joined Feb 2001, 155 posts, RR: 0
Reply 15, posted (13 years 7 months 2 weeks 5 days 22 hours ago) and read 2574 times:

In comparing airline fleets, I think it's also important to note that fleet commonality seems to be a more critical issue for smaller airlines than for major airlines. It may not be a concern for Northwest, for example (though in some respects that could be argued), but it's probably a serious financial consideration for airlines like JetBlue or National.

This is the time. And this is the record of the time.
User currently offlineB747skipper From , joined Dec 1969, posts, RR:
Reply 16, posted (13 years 7 months 2 weeks 5 days 20 hours ago) and read 2566 times:

Airlines replaced the old 747 classics (3 flight crewmembers) consisting of a captain + co pilot and engineer... with the 747-400 (2 flight crewmembers)...
With a crew of 3, the flight time limit is 12 hours...
The flight time limit with crew of 2... is 8 hours flight time...
All the 747 flights generally fly 10-12 hours legs...
Results, the 747-400 dispatched for a flight of 11 hours must have 3 crewmembers - which are captain + co pilot + ... captain -
The third crewmember has to be a captain, since whichever of the three is taking a rest, there MUST be a captain left in the cockpit on duty...
Bottom line - crew costs 11 hours flight is...
747 classic = $375.oo/hour x 11 = $4,125.oo flight pay
747-400 = $400.oo/hour x 11 = $4,400.oo flight pay
That much so far for crew savings...
Think also what is the annual debt service, of a $120,000,000 aircraft, compared to an aircraft that is paid-off... its cost are just operating and maintenance costs... the 10% fuel economy cannot justify that...
(s) Skipper

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