Rkmcswain From United States of America, joined Dec 2000, 222 posts, RR: 0 Posted (9 years 11 months 1 week 6 days 21 hours ago) and read 1427 times:
United Express 7567 (LEX->ORD) is currently delayed at LEX due to the "de-icer not working" (as was told to a passenger). This is a CRJ, what exactly does the "de-icer" do in 70° weather? Yes, I realize the temp drops as altitude rises. Are there certain altitudes where ice is a problem year round? Is this known to be a common problem with CRJ's? Any other comments? TIA
Gordonsmall From UK - Scotland, joined Jun 2001, 2003 posts, RR: 22
Reply 1, posted (9 years 11 months 1 week 6 days 21 hours ago) and read 1366 times:
OK, this is very much a stab in the dark, sort of like the blind leading the blind but.....
AFAIK In order for an airplane to fly into areas where Ice is known to be a factor, it has to be "certified for flight into known icing". One of the requirements of this is to have working de-iceing facilities for wings, engines etc.
If the de-icing equipment on the CRJ has gone belly up, and the flight is due to go through an area of known icing - it can't legally depart.
Just a guess.
Statistically, people who have had the most birthdays tend to live the longest.
Airplay From , joined Dec 1969, posts, RR:
Reply 2, posted (9 years 11 months 1 week 6 days 20 hours ago) and read 1308 times:
Well...Winnipeg isn't all that far from Chicago and its snowing like nobody's business here today. About 4 inches has accumulated on the ground so far and no sign of slowing down.
Flight need to be operationally capable of operating to the destination, AND the declared alternates. If it's snowing here, I would hazard a guess that similar weather could be in the vicinity of alternates to ORD today.
CRJ MMEL allows for operation with various de-ice components inoperative provided "Operations are not conducted in known or forecast icing conditions, and Both Ice Detection Systems are operative" so I assume the weather is to blame.
EMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 5, posted (9 years 11 months 1 week 6 days 17 hours ago) and read 1237 times:
Also..........Some system can not be MEL'd no matter what the weather conditions are...summer or winter. It all depends on what the airline has in their MEL Book. It may say 'If know icing is present you can't MEL the deicing system' and there may be thunderstorms in the area.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
Airplay From , joined Dec 1969, posts, RR:
Reply 6, posted (9 years 11 months 1 week 6 days 15 hours ago) and read 1220 times:
Winnipeg is ±717 miles from ORD (and ±1030 miles from LEX). Do flights normally divert to an airport 2.3 times the distance as the original destination?
No. The point I was trying to make was that if its snowing here, There is a fairly good chance that there are similar temperatures within a couple of hundred miles of here which may well fall into 45 minute alternates from Chicago. Of course the jetstream spoils that theory today as Winnipeg and Chicago are (as well as MSP) are separated by it.
Weather is often quite different on opposite sides of the jetstream even in locations that are quite close to each other.
One last thing...the weather around here usually heads for the great lakes on its way out the St. Lawrence. I wouldn't be surprised to hear areas near Chicago having relatively cold weather in a couple of days....
Rkmcswain From United States of America, joined Dec 2000, 222 posts, RR: 0
Reply 8, posted (9 years 11 months 1 week 6 days 14 hours ago) and read 1207 times:
Good enough guys, thanks.
BTW, the original flight (UAL7567) scheduled for a 10:46A departure, was cancelled. After several changes of plans (including being on the runway at one point in a NWA flight to DTW), they ended up on UAL7569 back to ORD which departed at 7:03P.
Pilotpip From United States of America, joined Sep 2003, 3139 posts, RR: 11
Reply 9, posted (9 years 11 months 1 week 6 days 11 hours ago) and read 1194 times:
Another big problem could arise from the wings being cold-soaked. The temperature drop at altitude has already been stated, but if the wing is thin enough it can cool the fuel and surface area as well. If the fuel is below freezing and you are in humid conditions the wings can frost. This is a very common problem on MD-80s but I don't know if it applies to the CRJs. Just a thought.
Prebennorholm From Denmark, joined Mar 2000, 6289 posts, RR: 54
Reply 10, posted (9 years 11 months 1 week 5 days 17 hours ago) and read 1159 times:
With 70 deg. on the ground you will most likely have freezing temp. at 10,000 feet, sometimes cosiderably lower. Fly through a cloud, and you may have massive ice bulid-up on the wing leading edge end engine inlets.
Clouds are micro water droplets which freeze instantly on impact with a wing which is only a franction of a degree below freezing.
There are very few places where you can operate a high flying commercial jet without de-icing operational even during the hottest summer. Such places would be the dryest deserts.
How many routes start in a desert, ends in a desert, flies all way over desert, and has all alternate airports in a desert?
Always keep your number of landings equal to your number of take-offs, Preben Norholm