Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
DC-8 Taking Off With Cascades Open?  
User currently offlineHappy-flier From Canada, joined Dec 1999, 299 posts, RR: 0
Posted (10 years 5 months 2 weeks 1 day 17 hours ago) and read 2428 times:

I just found this picture of a -50 series DC-8 taking off with the cascades open on engine #3. Is this a potentially dangerous situation? Can the bypass-reverse system engage in such a situation? I wonder if the crew would be able to correct this in flight, or whether they were even aware that it happened.

Link to picture.

[Edited 2004-03-22 19:08:20]


May the wind be always at your back . . . except during takeoff & landing.
5 replies: All unread, jump to last
 
User currently offlineBroke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 1, posted (10 years 5 months 2 weeks 1 day 16 hours ago) and read 2354 times:

While the shutters covering the cascades are slightly ajar, they are not open enough for the reverser to be deployed. In reverse, the shutters are perpendicular to the nacelle. Also, the shutters are covering the by-pass portion of the reverser, the hot stream is also reversed and that section is definitely not deployed.

User currently offlineTechrep From , joined Dec 1969, posts, RR:
Reply 2, posted (10 years 5 months 2 weeks 1 day 16 hours ago) and read 2355 times:


I have a lot of experience with those old cascade doors so allow me to answer. Based on what I see in this photo the top "louver" is missing and the louvers are slightly open.

The #3 engine is not in reverse because the cascade assembly is stowed. Remember this is a pneumatic thrust vectoring system and louver chatter or partially open partitions is not uncommon. There seems to be a pneumatic leak in the system allowing the louver doors not to stow properly.

The reason for this is a bad shuttle valve spring mechanism or people are injecting penetrating oil into the system or both. This penetrating oil makes the system function great for about 1 week, then it begins to gum up and the system will not function correctly. A common fix in a line maintenance environment and makes problems go away for a quick dispatch but this is not an approved maintenance practice.

I haven't seen one of these operate with one of the "Venetian blinds" missing expect by Kalitta and they’re a Mutha-F**er to change. In fact Cascade assemblies are so hard to change while at ABX we had stations dedicated to doing this task, with extra training and tooling. The system is entirely inefficient; they weigh a ton, break down about every other trip and constantly will not go into interlock and have lots and lots of pneumatic leaks.

TechRep



User currently offlineHappy-flier From Canada, joined Dec 1999, 299 posts, RR: 0
Reply 3, posted (10 years 5 months 2 weeks 1 day 15 hours ago) and read 2286 times:

Thanks very much guys. That just about says it all!


May the wind be always at your back . . . except during takeoff & landing.
User currently offlineHappy-flier From Canada, joined Dec 1999, 299 posts, RR: 0
Reply 4, posted (10 years 5 months 2 weeks 1 day 14 hours ago) and read 2204 times:

As I was reading through Techrep's reply, I got to wondering why Douglas ever went with the admittedly cumbersome nacelle design for the -50 and -61 series. Just comparing the cascade/"venetian-blind" assembly to the straight nacelle and single bucket-type reversers found on the -62 and -63 series aircraft, there's no comparison as to which is the better of the two systems - from a maintenance standpoint and, I would argue, that of performance as well.

All things told, the old turbojet nacelles with the aft-moving "sound suppressors" was even worse!!



May the wind be always at your back . . . except during takeoff & landing.
User currently offlineBroke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 5, posted (10 years 5 months 1 week 5 days 17 hours ago) and read 1922 times:

The entire nacelle for the DC-8-50 series and the DC-8-61's were developed by Pratt & Whitney and they were (and are in some places) maintenance and reliability headaches.

The entire nacelle for the DC-8-62's and -63's are Douglas designs and are much more superior in operation, ease of maintenance, and aesthetics than the early configurations.


Top Of Page
Forum Index

Reply To This Topic DC-8 Taking Off With Cascades Open?
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...
Taking Off With Just One Engine posted Wed Jul 5 2006 00:05:22 by Hagic
Taking Off With Tailwind posted Wed Feb 16 2005 00:39:47 by Bruce
Heavy Take-off With Tailwind posted Fri Oct 27 2006 20:02:52 by BA84
Could A 777 Take Off With One Engine Only? posted Tue Dec 27 2005 13:36:00 by LeDragon
Taking Off From A Road, How Not To.... posted Mon Oct 31 2005 16:20:38 by SATL382G
Taking Off Overweight posted Fri Jun 17 2005 19:59:01 by 762er
Take Off With Spoilers Up posted Tue Apr 19 2005 07:16:55 by AirWillie6475
DC-9 Take-off Flap Setting posted Tue Feb 15 2005 18:20:04 by Logan22L
Can A 4 Engined A/C Take Off With 1 Engine? posted Sat Nov 27 2004 10:46:37 by Emrecan
Can B744s/A345s Take Off With Only Two Engines? posted Sat Mar 6 2004 09:47:38 by StarG

Sponsor Message:
Printer friendly format