777fan From United States of America, joined Jan 2006, 2442 posts, RR: 3 Posted (3 years 3 months 3 weeks 2 days 2 hours ago) and read 5563 times:
Certainly good news for WN fliers into MDW although as a frequent flier out of ORD (and seemingly 22L), I find a less than 2 mile path somewhat disconcerting. Do we have any ORD or MDW-based drivers that have an opinion? Seems to me that despite the advent of 'new' GPS-equipped nav approaches, it'd take only a few seconds' worth of a distraction (weather, ATC, equipment issues) to possibly create a serious problem.
seven3seven From United States of America, joined Apr 2005, 313 posts, RR: 25 Reply 1, posted (3 years 3 months 3 weeks 2 days ago) and read 5362 times:
You think we're up there just winging it? The tolerances and precision of these approaches are incredible.
Have a little faith that we know what we're doing. Weather and ATC have nothing to do with it. There is no ground based equipment to fail. Airplane has multiple backups and flies the whole thing itself with us monitoring.
In fact these approaches make it more likely nothing will go wrong and there will be fewer delays.
My views are mine alone and are not that of any of my fellow employees, officers, or directors at my company
Read it again-- I guess what they mean is, if you flew straight in to rwy 13C at MDW you'd be within two miles of ORD 22L. Turns out even that isn't quite right.
The extended centerlines of the two runways cross at 41.91875 N 87.94037 W, which is 2.77 nm from the SW end of ORD 22L and 11.08 nm from the NW end of MDW 13C. Does that leave plenty of room for a curving approach?
apodino From United States of America, joined Apr 2005, 4015 posts, RR: 6 Reply 5, posted (3 years 3 months 3 weeks 1 day 17 hours ago) and read 4936 times:
The title of your thread is a little misleading, since it says MDW 31C. There is really no conflict between those ops, it is runway 13C that poses problems when ORD is departing 22L. Really, this procedure benefits only WN right now, since ORD dictates everything Chicago Tracon does, and WN has a near monopoly on MDW (I know DL, F9, and FL all serve there as well, but their presence is a lot more limited), and because WN is equipping their planes for this procedure (AA and AS are the only other two airlines I know for sure are equipping their planes as such based on news releases, but they are both ORD carriers anyways).
Where approaches like this are needed are airports that have airspace constraints where straight in approaches aren't possible (without seriously screwing up other airports, or noise abatement procedures). Runways that come to mind for this would be the 13's at JFK, 31 at LGA, 29 at EWR (Which I believe would allow 22's and 29 in use at the same time), 19 at DCA, and the 13's at DAL.
777fan From United States of America, joined Jan 2006, 2442 posts, RR: 3 Reply 6, posted (3 years 3 months 3 weeks 1 day 6 hours ago) and read 4146 times:
Quoting seven3seven (Reply 1): In fact these approaches make it more likely nothing will go wrong and there will be fewer delays.
My OP wasn't meant to imply that flight crews couldn't handle it however, I'm not convinced that the approach would necessarily cut down on delays for anyone other than WN since I'm not sure it'd be unlikely to benefit anyone other than those using 31C. I'm most curious to know what non-WN drivers think about the change.
Quoting apodino (Reply 5): The title of your thread is a little misleading, since it says MDW 31C. There is really no conflict between those ops, it is runway 13C that poses problems when ORD is departing 22L.
You obviously read the article; my OP contained a typo. Anyone that's departed on 22L and with even a minimal sense of bearing would know that it'd have to be 31C. MDW and its traffic aren't easy to miss if you're sitting on the starboard right of the cabin while departing 22L (and that's factoring in the 80 degree left turn immediately after wheels-up).
DrEsteban From United Kingdom, joined Aug 2009, 46 posts, RR: 0 Reply 8, posted (3 years 3 months 3 weeks 1 day 3 hours ago) and read 3607 times:
These type of approaches (GNSS/RNAV) are relatively common in many parts of
the world nowadays and are much more reliable/accurate then most non-precision
approaches (despite having equal or greater minima).
Also, in the above case the minimum RNP (Required Navigation Performance) is
0.30NM, try to achieve that sort of accuracy on an NDB or VOR approach!!
Another advantage of GNSS based approaches is the fact that they are not subject
to interference unlike the widely used ground based ILS. Also NDBs are very sensitive
to, for instance, thunderstorm activity and are notoriously inaccurate.
From a pilot's perspective this type of approach is great. On many types of aircraft
they are flown as a standard ILS with ILS type indications (LNAV/VNAV), therefore
the workload is much lower then on your average non-precision approach.
Your concern about a short turn to final is not quite justified; pilots around the world
do circling approaches/cloud-break procedures/visual approaches on a regular basis,
in many cases these types of approaches require a close in turn to final (anywhere
from 1.5-5NM !!). A pilot not comfortable to execute these types of maneuvers should
not get anywhere near an aircraft!
In summary, GNSS/RNAV approaches are ideal for airports which are restricted due to
airspace constraints, terrain, etc. They are cheap (no installation/maintenance cost),
reliable, accurate, easy to use and will reduce the workload for both controllers and
DiamondFlyer From United States of America, joined Oct 2008, 1370 posts, RR: 3 Reply 12, posted (3 years 3 months 3 weeks 1 day ago) and read 3045 times:
Quoting DrEsteban (Reply 8): Another advantage of GNSS based approaches is the fact that they are not subject
to interference unlike the widely used ground based ILS. Also NDBs are very sensitive to, for instance, thunderstorm activity and are notoriously inaccurate.
GPS is incredibly easy to jam, much easier to jam than a VOR or ILS would be, for instance. Signal strength is so low, that it doesn't take much to completely block the accurate signal.
DrEsteban From United Kingdom, joined Aug 2009, 46 posts, RR: 0 Reply 13, posted (3 years 3 months 3 weeks 23 hours ago) and read 2978 times:
That's why it is important to keep conventional navigation aids operational alongside GNSS
systems for the foreseeable future.
Don't forget that GNSS systems are closely monitored (like any other nav-aid) and when a
failure or jamming would occur reversion to conventional systems is still possible. There are
also many contingency procedures for both controllers and pilots in case of loss of signal or
loss of required RNP.
Point is that GNSS systems provide an excellent alternative for some of the very dated
systems we work with today. Yes, it certainly has its limitations but the limitations associated
with conventional systems are much greater. I believe the positives are outweighed by the
negative provided procedures are followed and contingency plans are in place.
DrEsteban From United Kingdom, joined Aug 2009, 46 posts, RR: 0 Reply 14, posted (3 years 3 months 3 weeks 22 hours ago) and read 2849 times:
Just to be clear, I am not lobbying for a total replacement of conventional navigation.
I just believe that in many cases GNSS can be very useful. For instance, look at a lot of
airports in mountainous parts of the Rockies, Alaska, New Zealand, Australia, Norway, etc.
There it provides a good alternative when a straight-in approach can't be made due to terrain
restrictions. Without it some places would be virtually impossible to fly into.
Also airports where airspace restrictions exists (like MDW) would potentially benefit from
implementation of GNSS/RNAV procedures.
There are of course cases where GNSS cannot (yet) replace current technology, for instance
in CATII/III (autoland) conditions. This might change in the future with the addition of ground
based systems like LAAS/GBAS.
It is really a true shame MLS (Microwave Landing System) was never widely implemented,
although some say MLS might see a revival. There are some benefits associated with this
system; curved approaches and reduction of spacing between aircraft in LVP conditions due
to the fact this particular systems is not susceptible to ground interference. I believe BA has
recently equipped some of its Airbusses with MLS receivers for this reason.