DC9RHI
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Flight Routing - NYC To Miami

Thu Oct 24, 2013 4:04 pm

According to flight tracking map, why would a Delta MD-88 follow the coastline from LGA to MIA, but a JetBlue A320 on same routing at same time, cut across Atlantic at roughly Wilmington, NC and head straight to MIA. Is it due to the equipment used?
 
flymia
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RE: Flight Routing - NYC To Miami

Thu Oct 24, 2013 4:27 pm

Well the A320 could have over water equipment while the MD-88 does not. Like life vest. Also it could be congestion on certain airways. I am not sure what the regs are on airliners without over water equtiment and how far away from shore they can get. I am not talking ETOPS just things like life vest. I recently flew on an MD-88 on DL and don't remember if they have life jackets or not.
"It was just four of us on the flight deck, trying to do our job" (Captain Al Haynes)
 
Airontario
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RE: Flight Routing - NYC To Miami

Thu Oct 24, 2013 4:29 pm

Quoting flymia (Reply 1):

In Canada if a plane stays within 50nm of land it does not need to have life vests on board. I assume its something similar in the USA.
 
MesaFlyGuy
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RE: Flight Routing - NYC To Miami

Thu Oct 24, 2013 4:29 pm

The a320s cruise higher than MD-88s so may e that plays a factor? Also I know a handful of DL's MadDogs over limited overwater equipped so perhaps the flight in question was one that ISN'T equipped? I think it would be too early in the flight to factor in their separate destinations.
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Dalmd88
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RE: Flight Routing - NYC To Miami

Thu Oct 24, 2013 8:05 pm

All DL MD88 have life jackets. Only a few have life rafts. I can't recall the reg limits, the jackets let you fly farther but not as much as the raft does.
 
Mir
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RE: Flight Routing - NYC To Miami

Thu Oct 24, 2013 10:33 pm

If you don't have life rafts onboard (not just vests), you can't go more than 50 miles from shore.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
DC9RHI
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RE: Flight Routing - NYC To Miami

Fri Oct 25, 2013 3:57 am

Quoting Mir (Reply 5):

Wouldn't it be a lot cheaper to buy some rafts? We're talking about flying quite a few extra miles having to hug the coast. I find it hard to believe that they are willing to burn extra fuel, add time to the flight, hours on the airframe, engines, and flight crew just to not equip the plane with rafts? Seems unlikely.
 
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Starlionblue
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RE: Flight Routing - NYC To Miami

Fri Oct 25, 2013 5:04 am

Quoting dc9rhi (Reply 6):
Wouldn't it be a lot cheaper to buy some rafts? We're talking about flying quite a few extra miles having to hug the coast. I find it hard to believe that they are willing to burn extra fuel, add time to the flight, hours on the airframe, engines, and flight crew just to not equip the plane with rafts? Seems unlikely.

It would if these were the only routes the planes fly. However the planes probably mostly fly overland. Adding the rafts add maintenance costs. More importantly, their weight is not trivial, meaning higher fuel burn on every single sector.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
BigSaabowski
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RE: Flight Routing - NYC To Miami

Fri Oct 25, 2013 1:27 pm

Quoting Mir (Reply 5):


If you don't have life rafts onboard (not just vests), you can't go more than 50 miles from shore.

You can get an exemption from the FAA that will let you go 100nm offshore (north of the 35th parallel) or 162nm (south of the 35th) without rafts. It is not that difficult to get.
 
Mir
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RE: Flight Routing - NYC To Miami

Fri Oct 25, 2013 2:48 pm

Quoting dc9rhi (Reply 6):
Wouldn't it be a lot cheaper to buy some rafts? We're talking about flying quite a few extra miles having to hug the coast. I find it hard to believe that they are willing to burn extra fuel, add time to the flight, hours on the airframe, engines, and flight crew just to not equip the plane with rafts? Seems unlikely.

It's actually only about 50nm extra to go down the coast, which is an extra 5-10 minutes or so. So the difference isn't as great as you'd think. Rafts are expensive to buy and maintain, so is the training to use them for the crew. Unless you're doing extended overwater with a particular fleet on a regular basis, it doesn't make a whole lot of sense to put them on just for the occasional flight.

Quoting BigSaabowski (Reply 8):
You can get an exemption from the FAA that will let you go 100nm offshore (north of the 35th parallel) or 162nm (south of the 35th) without rafts. It is not that difficult to get.

I do see a lot of DL MD-88s doing the overwater route between JFK and MIA recently, so perhaps they have the exemption and the coastal route was due to some temporary equipment issue or something like that.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
MSJYOP28Apilot
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RE: Flight Routing - NYC To Miami

Fri Oct 25, 2013 3:17 pm

I havent read the Delta FOM in a while but most major airlines and some regionals like Endeavor and ExpressJet (ASA side) have the over water exemption granted by the FAA to save on the costs of maintaining and training for life rafts on a plane. As Saabowski mentioned, it allows carriers to go between 100-160 nm offsore depending on the geographic location.

The WATRS airspace that carriers use to get to Florida and the Caribbean over the Atlantic require specific navigation performance. Company policy and MEL limitations further can limit your ability to operate WATRS airspace.

For example, many aircraft at an airline have dual FMS/GPS installed but certain operations require both to be operative. Company policy might also require both to operative. Therefore, having a single FMS or GPS deferred could mean the flight would need to use over land routes instead of the over water routing.

When you are over water far enough away from the shoreline, you are out of the range of the land based navaids. Thus a plane needs a way to navigate being too far away from the service range of the VOR/NBDs on land. GPS navigation and IRS systems are the primary means today of navigating outside of the service volumes of land based navaids.

This means airlines want and the FAA requires through the MEL book and the over water exemption terms a way to have multiple working backup systems where navigation is not predicated on the use of land based navaids.

If an airline had a choice to spend hours trying to fix a GPS system or to fly over land and burn maybe a little more gas, it will choose almost every time to operate the flight on time regardless of the increased burn enroute. A plane sitting a gate isnt making money.

[Edited 2013-10-25 08:19:21]

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