Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Alternate Departure Airport  
User currently offlineAirWillie6475 From United States of America, joined Jan 2005, 2448 posts, RR: 1
Posted (8 years 9 months 3 weeks 2 days 19 hours ago) and read 13437 times:

For you airline pilots out there, is there such thing as a alternate departure airport? If there is, why is there a need for an alternate airport?

7 replies: All unread, jump to last
 
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 1, posted (8 years 9 months 3 weeks 2 days 19 hours ago) and read 13432 times:

In some cases you can dept with lower minimums than you can land with therefore you have an alt that you can go to in the event of an emerg. after dept.

User currently offlineJspitfire From Canada, joined Feb 2005, 308 posts, RR: 2
Reply 2, posted (8 years 9 months 3 weeks 2 days 18 hours ago) and read 13419 times:

I just learned about this in groundschool. For most departures, the minimum visibility is 1/2 SM, and there is no minimum ceiling. So, this means that if the weather is really bad, you can likely depart, but you probably won't be able to get back in.

If I remember correctly, the alternate has to be within 60 minutes flight time at the aircraft's single-engine cruise speed. If the aircraft is certified for ETOPS, then I think it goes up to 120 minutes. I should know this, considering I had a test on it today, but if I'm wrong, please correct me.

Jason


User currently onlineGoldenshield From United States of America, joined Jan 2001, 6118 posts, RR: 14
Reply 3, posted (8 years 9 months 3 weeks 2 days 18 hours ago) and read 13405 times:

I can only speak for U.S. regulations.

First, the regulations in question:

§ 91.1039:

(d) No person may take off an aircraft under IFR from an airport where weather conditions are at or above takeoff minimums but are below authorized IFR landing minimums unless there is an alternate airport within one hour's flying time (at normal cruising speed, in still air) of the airport of departure.

-----------------

§ 135.217 IFR: Takeoff limitations.
No person may takeoff an aircraft under IFR from an airport where weather conditions are at or above takeoff minimums but are below authorized IFR landing minimums unless there is an alternate airport within 1 hour's flying time (at normal cruising speed, in still air) of the airport of departure.

------------------

§ 121.617 Alternate airport for departure.
(a) If the weather conditions at the airport of takeoff are below the landing minimums in the certificate holder's operations specifications for that airport, no person may dispatch or release an aircraft from that airport unless the dispatch or flight release specifies an alternate airport located within the following distances from the airport of takeoff:

(1) Aircraft having two engines. Not more than one hour from the departure airport at normal cruising speed in still air with one engine inoperative.

(2) Aircraft having three or more engines. Not more than two hours from the departure airport at normal cruising speed in still air with one engine inoperative.

(b) For the purpose of paragraph (a) of this section, the alternate airport weather conditions must meet the requirements of the certificate holder's operations specifications.

----

Part 91 requires a takeoff alternate within 1 hour's flight if the departure airport is below minimums, but it does not specify what kind of airport,or wether that airport should be forecast above landing minimums at the arrival time.

Part 135 reads the same as 91. While both 91 and 135 mention minimums required to list an arrival alternate, that rule is not extended to the takeoff.

Part 121, however, is a whole different ball game. Firstly, number of engines on the aircraft fall into play, requiring a maximum 1/2 hour for twins, and 1 hour for those with 3 or more engines. Secondly, the regulation states that the weather conditions (forecast) at the alternate must be above alternate landing minimums, as required by 121, or as allowed in that carrier's OpSpecs.



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineCYLW From Canada, joined Apr 2000, 438 posts, RR: 0
Reply 4, posted (8 years 9 months 3 weeks 2 days 11 hours ago) and read 13370 times:

Quote:
Part 121, however, is a whole different ball game. Firstly, number of engines on the aircraft fall into play, requiring a maximum 1/2 hour for twins, and 1 hour for those with 3 or more engines. Secondly, the regulation states that the weather conditions (forecast) at the alternate must be above alternate landing minimums, as required by 121, or as allowed in that carrier's OpSpecs

For twins, isn't it 1 hour at the one engine speed??


User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 9 months 3 weeks 2 days 11 hours ago) and read 13365 times:

Quoting Goldenshield (Reply 3):
Part 121, however, is a whole different ball game. Firstly, number of engines on the aircraft fall into play, requiring a maximum 1/2 hour for twins, and 1 hour for those with 3 or more engines.

That's one hour for twins; two hours for 3- or 4-engined birds...

(1) Aircraft having two engines. Not more than one hour from the departure airport at normal cruising speed in still air with one engine inoperative.

(2) Aircraft having three or more engines. Not more than two hours from the departure airport at normal cruising speed in still air with one engine inoperative.

Back to recurrent!  Wink


User currently onlineGoldenshield From United States of America, joined Jan 2001, 6118 posts, RR: 14
Reply 6, posted (8 years 9 months 3 weeks 2 days 5 hours ago) and read 13347 times:

Oops. My bad. I had just pasted the regulation, too.  Wink

I have no idea what I was thinking there. Perhaps I should stop posting when I'm 1/2 asleep.  Wink



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 9 months 3 weeks 2 days 4 hours ago) and read 13340 times:

Quoting Goldenshield (Reply 6):
I have no idea what I was thinking there. Perhaps I should stop posting when I'm 1/2 asleep.

Nah, it's just CVL (cranial vapor lock)--it happens to everyone at one point or another..  Wink


Top Of Page
Forum Index

Reply To This Topic Alternate Departure Airport
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
A340 Departure Airport Question posted Sun Aug 29 2004 08:31:46 by Jc2354
Airport Design - Arrival Vs. Departure Floor posted Wed Oct 25 2006 05:08:15 by Abrelosojos
Kai Tak Airport Departure/arrival Procedures posted Fri Aug 8 2003 05:42:52 by Undies737
Airport '77 posted Mon Nov 13 2006 01:19:36 by Jamincan
Anyone Landed At Wrong Airport Or Runway? posted Fri Nov 10 2006 12:33:28 by Redcordes
La PAz Airport: Has It Special Features posted Sun Oct 22 2006 10:21:33 by F.pier
GA Airport Fuel Statistics posted Tue Sep 19 2006 22:59:50 by 762er
Displaced Thresholds, Lupepau'u Airport posted Sun Aug 20 2006 02:37:12 by NZ8800
Busiest Class C Airport? posted Thu Aug 17 2006 20:50:46 by Squawk0303
Airport Management Software posted Thu Jul 20 2006 22:48:01 by YOWza
Alternate Airport For LHR posted Mon Oct 1 2007 18:54:32 by CoolGuy
Airport Design - Arrival Vs. Departure Floor posted Wed Oct 25 2006 05:08:15 by Abrelosojos
Kai Tak Airport Departure/arrival Procedures posted Fri Aug 8 2003 05:42:52 by Undies737
Difference Between Runway And Departure posted Tue Apr 24 2012 05:50:54 by smartt1982
Questions About TSA / Airport Exit Lanes posted Thu Apr 19 2012 23:13:53 by AlnessW
Delta Connection, Pre Departure Drinks posted Sat Feb 4 2012 20:23:55 by davescj
LGA Airport Badge posted Mon Jan 30 2012 16:54:17 by sid1975
Can An Airport Change Its Code? posted Sun Jan 22 2012 10:48:14 by mkh32404

Sponsor Message:
Printer friendly format