Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
APU Windmill Starts On MD80s?  
User currently offlineBio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7
Posted (11 years 11 months 3 weeks 2 days 10 hours ago) and read 1649 times:

Hi all.

In a recent post I read an FBU 4ever post where he stated MD80s performed APU windmill starts. Is this also a practice on larger aircraft as the Airbusses and Boeings? And also, is the procedure for these starts just opening the APU intakes?

Thanks in advance

-Alfredo

3 replies: All unread, jump to last
 
User currently offlineCdfmxtech From United States of America, joined Jul 2000, 1341 posts, RR: 27
Reply 1, posted (11 years 11 months 3 weeks 2 days 8 hours ago) and read 1620 times:

Of the aircraft I've had the opportunity to work, the MD80 is the only one with this feature. Not on the 737,757,767,777.
If the MD80 loses L & R AC Power inflight, the starter is disabled. The Ram Air Doors open fully and allow the APU to windmill start.

The 737 starter is available as long as the battery has power. The 757, and B767 starters are available as long as both batteries have power. The B777 is similar to the 757/767, but it has an additional pneumatic starter for the APU.

As for the start procedure, you just start the APU door normally. The RAM doors switch is supposed to be in normal for the start, and it will go to the RAM position for the start. And with aircraft going as fast as it is, the ram air gets the APU moving, as I understand it fairly quickly.


User currently offlineBio15 From Colombia, joined Mar 2001, 1089 posts, RR: 7
Reply 2, posted (11 years 11 months 3 weeks 2 days 7 hours ago) and read 1618 times:

Very interesting Cdfmxtech, I wonder why Boeings don't have this mechanism. It could be a last resource in case of full electrical loss I assume!



>>>The B777 is similar to the 757/767, but it has an additional pneumatic starter for the APU.
Does this mean there has to be a compressed air reserve? or simply that engine bleed air is ducted all the way to the APU turbine?

-Alfredo


User currently offlineCdfmxtech From United States of America, joined Jul 2000, 1341 posts, RR: 27
Reply 3, posted (11 years 11 months 3 weeks 2 days 6 hours ago) and read 1602 times:

Well, first off, in a COMPLETE electrical loss, you won't get an -80 APU started either. Needs the battery.
It was pretty smart of Douglas (Did I say that). Disabling that APU starter can save use on the battery during an emergency and give u a couple of extra minutes.

As for the B777, it uses the pneumatic starter whenever the manifold is pressurized...be it by engine bleeds or ground air carts. There is no compressed air reserve.


Top Of Page
Forum Index

Reply To This Topic APU Windmill Starts On MD80s?
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...
APU Looks Plugged On This Test Airplane posted Sat Aug 19 2006 14:17:49 by CURLYHEADBOY
Spray Deflector On B717, MD80s And MD90s? posted Fri Aug 25 2006 22:21:31 by Ferret
Need Info On 767 APU posted Wed Oct 26 2005 03:44:38 by FlyMKG
Jet Engine Windmill On Descent posted Tue Aug 9 2005 21:05:53 by Taguilo
APU On A 747 (Where Is The Air Intake?) posted Mon Aug 23 2004 23:10:47 by BandA
Busted APU On 737? posted Thu Jul 29 2004 18:45:34 by Radelow
APU's On USAirways Express Dash 8s posted Wed Dec 24 2003 19:47:31 by ExpressJet_ERJ
Where Are The APU's Located On The BAe 146/Avro RJ posted Mon Aug 20 2001 01:27:53 by BA
Pressure Gauge Near APU On 737 posted Sun Jun 24 2001 05:27:43 by UAL Bagsmasher
APU On/pff posted Sun Feb 18 2001 20:26:43 by Modesto2

Sponsor Message:
Printer friendly format