SWA...Boeing question
12-15-2011 | 09:20 AM
#11
Gets Weekends Off
Joined: Jun 2007
Posts: 1,207
Likes: 0
From: CA
Actually no.....In prepping for 73 ground school I found that Boeing recommends periodic run-ups on the ground in icing conditions....with take-off being preceded by a fairly lengthy static run-up (30 seconds?)...was wondering if this is accurate and figured the SWA folks would know if anyone would.
12-15-2011 | 09:48 AM
#12
Gets Weekends Off
Joined: Sep 2006
Posts: 537
Likes: 0
From: Q400 survivor
I think its a fairly standard procedure for any plane with engines hung low from the wings.
on the 170 our manuals suggest a 30 second runup every so often if in icing conditions on the ground, or if we think we might injest snow/ice on the ground (aka, its clear, but the taxiways are covered with 4" of powdery snow)
on the 170 our manuals suggest a 30 second runup every so often if in icing conditions on the ground, or if we think we might injest snow/ice on the ground (aka, its clear, but the taxiways are covered with 4" of powdery snow)
12-15-2011 | 10:29 AM
#13
Runs with scissors
Joined: Dec 2009
Posts: 7,847
Likes: 0
From: Going to hell in a bucket, but enjoying the ride .
You may want to consider a pre-takeoff run up in icing conditions regardless of what the book says:
Air Florida 90 Crash In 1982 - Washington, DC - YouTube
12-15-2011 | 01:26 PM
#14
Gets Weekends Off
Joined: Jul 2008
Posts: 299
Likes: 0
From: 737 f/o
Can't speak for Southwest but here's what Alaska's policy is….we operate in icing conditions from time to time:
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
12-15-2011 | 02:52 PM
#15
Thread Starter
Gets Weekends Off
Joined: Sep 2009
Posts: 335
Likes: 0
Certain types of freezing precipitation do warrant a periodic run up and pre-takeoff static run up at SWA. My best recollection is freezing rain, freezing fog, or any time there is unusual vibrations due to build up on the fan blades. I have to admit I have not de-iced yet this year, so it's been a while since I've read up on it.
Thanks for the response Shoelu,
The recommendations re run up length (in time) and intervals between run ups, all dependent on OAT and precip types seem fairly convoluted...
12-15-2011 | 02:55 PM
#16
Thread Starter
Gets Weekends Off
Joined: Sep 2009
Posts: 335
Likes: 0
Can't speak for Southwest but here's what Alaska's policy is….we operate in icing conditions from time to time:
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
12-15-2011 | 03:28 PM
#17
Gets Weekends Off
Joined: Jul 2008
Posts: 299
Likes: 0
From: 737 f/o
an additional run-up isn't required but typically do the run-up on the runway since the area behind you is guaranteed clear. It's all based on the 10 or 30 minute interval where and when you do it.
side note…freezing fog (FAI, BRW, SCC etc) sticks to the fan blades pretty bad on the taxi-in so in those instances they duct hot air into the intakes prior to start-up and then get on the 10 minute interval from there.
side note…freezing fog (FAI, BRW, SCC etc) sticks to the fan blades pretty bad on the taxi-in so in those instances they duct hot air into the intakes prior to start-up and then get on the 10 minute interval from there.
12-15-2011 | 03:38 PM
#18
Gets Weekends Off
Joined: Mar 2008
Posts: 1,133
Likes: 0
From: DAL Pilot
Can't speak for Southwest but here's what Alaska's policy is….we operate in icing conditions from time to time:
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
When engine anti-ice is required and the OAT is 3^C or below, do an engine run-up as needed, to minimize ice buildup. Engine run-up is defined as 70% N1 for approximately 30 seconds duration at intervals no greater than 30 minutes.
note: When operating in conditions of freezing rain, freezing drizzle, freezing fog or heavy snow, run-ups to a minimum of 70% N1 for approximately 1 second duration at intervals no greater than 10 minutes enhance ice shedding.
12-15-2011 | 03:49 PM
#19
Runs with scissors
Joined: Dec 2009
Posts: 7,847
Likes: 0
From: Going to hell in a bucket, but enjoying the ride .
And it's the same on the 777.
Now, what does the 737 use to set takeoff power? EPR or N1? I only ask because frozen EPR probes is what caused that 1982 Air Florida crash. I was always taught to double check the N1 and N2 when setting takeoff power. The EPR indication can be in error, caused by a stray bumble bee, or ice and snow.
N2 is pretty reliable, if you don't have at least 92% N2, stop and figure out why not.
Now, what does the 737 use to set takeoff power? EPR or N1? I only ask because frozen EPR probes is what caused that 1982 Air Florida crash. I was always taught to double check the N1 and N2 when setting takeoff power. The EPR indication can be in error, caused by a stray bumble bee, or ice and snow.
N2 is pretty reliable, if you don't have at least 92% N2, stop and figure out why not.
12-15-2011 | 04:05 PM
#20
Gets Weekends Off
Joined: Jul 2008
Posts: 299
Likes: 0
From: 737 f/o
Not a lot of EPR gauges these days I don't think. On some DC-9s and 737 200s but nothing on NGs or 400s that I know of. I can't speak for bigger AC. You are correct though, it was a blocked PT2 probe (I think) and cross-checking N2 is kinda important.
Thread
Thread Starter
Forum
Replies
Last Post
