MSP Hint of the Month for July 2012

Just when you thought it was safe to go back into the Forum…..another MSP “Hint of the Month” OK, maybe “Hint” isn’t just the right word. How bout “mini-tutorial”. I’ll try to keep it short.

This month it’s about MSP Flight Schedules. This comes to mind because I’ve just completed a revision of the MSP Cat IV schedule. We should be posting the revised schedule soon. Actually, it’s a replacement, not a revision. It is part of a complete reworking of the MSP flight schedules that I inherited from my predecessor. I have now replaced the Cat I, II, III, VII and IV schedules. Just two more to go: V and VI. There are several reasons for doing this. First, I wanted a more comprehensive schedule. It still doesn’t look like the schedule of a “real” (i.e., non-virtual) airline, because we don’t have multiple flights between city pairs like a real airline. What good would that do, only the departure and arrival times differ. However, I am aiming to have a comprehensive schedule, just like a real airline. I am also trying to have a “continuous” schedule in the sense that, if I assign (or your fly) a continuous set of flight numbers, you will be able to keep the same aircraft for the whole thing – you won’t have to “deadhead” from one destination to the next origin. Why should that matter? Well, I want your assignments to make sense and I don’t want to hunt through the schedule to connect one flight to the next and then have to issue your assignments one flight at a time.

So that brings up another question. What is the difference between the various categories of aircraft? It’s obvious that the aircraft get bigger as you ascend the sequence. In fact, our Cat I, II, III …aircraft are defined by their weight. The best measure of that is the maximum gross takeoff weight (GTW). That varies from about 30,000 lbs for a Cat I aircraft to over 600,000 lbs for some Cat VII aircraft. There are corresponding variations for the passenger capacity (20 – over 500) and range (1000 NM to 7000 NM). Note that the variations in weight and passenger load (factors of about 20) are greater than the variation in range (a factor of 7). So, the lower category aircraft characteristically serve smaller destinations, but not necessarily correspondingly shorter distances. Thus we might see a CRJ-700 (Cat III) connecting a hub to a small city 1200 NM away, but an A319 (Cat V) connecting to a city 350 NM away. So, while it is generally true that the higher category aircraft are assigned to the longer trips, they also tend to be to the larger cities. I recently completed a development flight from Minneapolis (KMSP) to Yellowknife (CYZF), a four hour flight, in an ERJ-145XR, a Cat II aircraft. I completed the flight with about 20% of my fuel load remaining, admittedly a little under FAA required minimums, but close. I considered adding this flight to the Cat II schedule, but decided not to when I realized that I had insufficient fuel to reach an alternate with a sufficiently long runway.

When you look at one of our schedules, bear the following points in mind. All the times are local times. That’s because airline schedules are posted in local time at the origin and destination so as not to confuse the customers. It’s a great idea to record start up and shut down times in GMT (Zulu), but don’t forget that the “published” schedules show local time. If you find times on the schedule that don’t work, let me know and I will correct the schedule. The schedule mileages are not the great circle point to point distance. That’s because commercial aircraft under ATC control generally fly airways (and SIDs and STARS) which are not direct routes. Since the actual flight plans vary, I have used a “fudge factor” of 15% above the great circle distance. That’s about the same factor the big guys (United, Delta, etc.) use. The flight times also vary, because of varying routes, varying headwinds, and (particularly) varying taxi times, which depend on traffic at the origin and destination. Like the majors, we use a comfortable margin on the minimum flight time so that our “on time arrival” numbers will be competitive . Again, if you find the schedule times out of whack, let me know.

A word of warning: Before you commit to a flight, make sure there is enough runway at all of your destinations (some flights have three!) to accommodate your aircraft. If not, pick a smaller aircraft. Nothing says you need to use a Cat IV aircraft to fly a Cat IV route.

Even if you have already passed through your period as a Cat IV First Officer, check out the new Cat IV schedule. You will find a lot of destinations never before served by SPA flights.

I said I’d keep this short, didn’t I? Sorry.

Mike Daugherty
SPA 48
MSP Hub Manager

The new MSP CAT IV schedule is now posted.

Mike