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Joined: Fri Sep 08, 2000 1:44 am

"Irregular Operations" In DTW

Fri Jan 07, 2005 7:18 am

For some reason, NW had planes overflying DTW today due to "irregular operations." Does anyone know what was up?

Departs: Newark Int'l, NJ ( EWR ) Arrives: Detroit-Wayne County Int'l, MI (DTW)
Gate: 40 Gate:
Scheduled: 7:20AM Scheduled: 9:25AM
Actual: 7:50AM Actual: Overflown
Aircraft: DC9-30 Weather: DTW
Note: Overflown due to irregular operations.
Status: Unscheduled Route

Departs: Detroit-Wayne County Int'l, MI (DTW) Arrives: Grand Rapids-Int'l, MI ( GRR )
Gate: Gate: A2
Scheduled: 10:15AM Scheduled: 11:06AM
Actual: Overflown Actual: 9:57AM
Aircraft: DC9-30 Weather: GRR
Note: Overflown due to irregular operations.
Status: Unscheduled Route
Posts: 313
Joined: Tue Dec 09, 2003 9:23 pm

RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 7:23 am

it was snowing,and sleeting, at DTW till noon, probably had a part in all that.
the rumble of round engines is like music to me,likewise the thunder of thr JT8D
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RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 7:56 am

It snowed for two days and there was freeezing rain earlier in the day. Entire school districts were closed due to the weather early today. I live 2 miles from the airport and this morning the roads were very bad and the freezing rain kept sticking to my windshield.
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Joined: Thu Feb 12, 2004 1:05 am

RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 9:10 am

It was to thin out the schedule in DTW on a day where there would be major delays due to the ice and freezing rain. Inbounds to DTW would be subject to massive ground delays at the departure stations, causing most passengers to miss onward connections. It would also cause the aircraft and flight crews to be late for their next sector. End result would be that crews and aircraft would be out of position / crews would run out of duty time / the other hubs would also be affected by the knock-on effect. In other words, a large part of the hub and spoke system through all the hubs could be impacted by bad weather in one hub. It can also lead to delays the next day too as the airline scrambles to get crews and airplanes back on schedule.

One solution is to overfly the hub with the bad weather in order to keep both the aircraft and flight crew flying. Perhaps the next sector would have been GRR-MSP, so this allows them to protect this flight and several other later flights too. Operations Planning plan ahead when weather events like this occur - they will look at ways to operate most efficiently given the known certainties of these weather events. I know it doesn't appear to make much sense to fly past DTW either empty or with however many passengers were travelling on to GRR, but this is far cheaper in the long term because of keeping the other hubs operating. Most of the other passengers on EWR-DTW would have been booked on Continental to their final destinations, so the local passengers to DTW are the only ones badly affected by the weather.

They do this quite effectively with as many flights as needed based on the anticipated conditions at DTW. This also has the added benefit of reducing ground delays on those flights they chose to operate into DTW. This will also allow for less deicing delays outbound from DTW, so again, it keeps the aircraft moving rather than being snarled up. Incidentally, this all came about after the infamous DTW snowstorm event a few years ago when people were stranded on aircraft for hours. Another thing they will do is cancel many Airlink flights into the affected hub on the premis that an A320 full of passengers landing in the hub is a better economic proposition than an RJ with 40 passengers onboard. This also occured in MEM with the recent icestorm.
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RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 12:45 pm

Really, really stupid question but I can't pick up the answer from either context or Google:

What does "overfly" mean in this sense?

I know overfly as in "do not overfly the elementary school SW of airport", but this seems to have a different meaning.


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Joined: Thu Feb 12, 2004 1:05 am

RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 2:39 pm

Lincoln, what is happening here is that flights scheduled to fly into DTW were instead flying directly to the next destination of the aircraft in order to keep the schedule intact. In the example given by Venuscat an aicraft scheduled to operate EWR-DTW, then DTW-GRR was instead routed directly to GRR. The aircraft could then continue its routing out of GRR onschedule, probably to MSP without causing a huge knock-on effect of delays and misconnects for the rest of the day caused by the weather in DTW.
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RE: "Irregular Operations" In DTW

Fri Jan 07, 2005 4:49 pm

The weather in DTW was the biggest joke today.
The media had this storm hyped up to be the biggest thing to hit the city in the past decade.

It came nowhere even close, we got a whopping 4-5" out it. They closed all the schools and everything. The roads where fine, and DTW kept right up with the storm.