Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Autopilot Disconnects On Commercial Jets  
User currently offlineSevenheavy From United Kingdom, joined Mar 2004, 1156 posts, RR: 10
Posted (10 years 6 months 4 weeks 1 day 7 hours ago) and read 4707 times:

Something I have often wondered is how soon into the descent is it feasible/preferable to disconnect the autopilot and hand fly a large commercial aircraft (i.e.a320, 747, 757 etc. etc. ) down to approach and landing. Assuming it was a clear day with excellent flying conditions could you hand fly from TOD or is that just not feasible, or even allowed under normal operations?. With that in mind is there a point whereby it is considered "normal" to disconnect and hand fly an approach(weather permitting)?.
If any flight deck or anyone else in the know could offer an insight I would be very grateful.
(I have searched and could'nt find a similar post, however my apologies if I missed something).

Regards,

SevenHeavy.


So long 701, it was nice knowing you.
20 replies: All unread, jump to last
 
User currently offlineWing From Turkey, joined Oct 2000, 1573 posts, RR: 24
Reply 1, posted (10 years 6 months 4 weeks 1 day 7 hours ago) and read 4650 times:

Hi Sevenheavy,
I don't fly the aircraft you stated but I fly 737,what I say will apply to most airliners .First I'd like to explain a few things about the autopilot usage.An airliner pilot has a lot of other works in cockpit during a flying day so instead of actively manuplating with yoke we use the autopilot.(AP) The use of the AP helps a lot to reduce the workload,provides more passenger comfort,helps fuel save.But I have to add AP flies the airplane,pilot flies the autopilot.

Now during approach,especially in busy airspaces where alot of traffic around you in close distances,alot of radio chatter going on,approach planning of your airplane(not to be high or low than required)while trying not to get closer to traffic infront of you and not to let the traffic behind you catch you,and keeping the track instructed by the ATC,doing briefings and checklists,and etc etc.AP is the most helpful tool to use.(may he rest in piece whoever invented it)

My company policy suggests that we use the AP until 1000' during good weathers,and until seeing the runway visually in poor conditions.There are times when we once in a while want to have some fun and keep the skills sharp especially during ferry flights(no passengers) where we actually handfly the all approach with no FD's and AT's.But in everyday operations we use the AP mostly.I hope I could be helpful.Regards.WING



Widen your world
User currently offlineDC-10Tech From United States of America, joined Jun 2001, 298 posts, RR: 2
Reply 2, posted (10 years 6 months 4 weeks 15 hours ago) and read 4462 times:

I agree with Wing. There is a lot going on in the flight deck and I for one am glad that the autopilot is keeping track of some of those things! If you are ever able to sit in the flight deck on approach into a busy airport, you will be amazed at how much is going on. Both pilots (and FE, if equipped) are on the radios, checking charts, tuning nav equipment, looking for traffic, you name it! It gives me piece of mind to know that they can set in a 10,000 foot level off at 220kias and the autopilot/autothrottle will take care of that while they do other things!


Forums.AMTCentral.com
User currently offline707cmf From France, joined Mar 2002, 4885 posts, RR: 29
Reply 3, posted (10 years 6 months 4 weeks 15 hours ago) and read 4458 times:

On my last jumpseat ride on a AF319 (sorry, no picture plugging today), the captain disconnected the AP way before 10,000 (around FL 190), he wanted to expedite the descent manually (the FO was not even in the flight deck at that time !!!)

707


User currently offlineDufo From Slovenia, joined May 1999, 801 posts, RR: 4
Reply 4, posted (10 years 6 months 4 weeks 15 hours ago) and read 4458 times:

A little bit off-topic maybe..
WING, how much/when do you use the CWS a/p mode?



I seriously think I just creamed my pants without any influence from any outside variables.
User currently offlineWing From Turkey, joined Oct 2000, 1573 posts, RR: 24
Reply 5, posted (10 years 6 months 4 weeks 13 hours ago) and read 4453 times:

Dufo,
We almost never use CWS mode in normal day operations,nor we do have any usage of it specified by company SOP.The only time comes in my mind,it is used (as its said by the more experienced captains)during heavy turbulance to help maintain control of the airplane.Other than that it only comes in whenever one of the pitch or roll modes are missing and the AP is engaged.
WING.



Widen your world
User currently offlineCX flyboy From Hong Kong, joined Dec 1999, 6615 posts, RR: 55
Reply 6, posted (10 years 6 months 4 weeks 10 hours ago) and read 4437 times:

Wing has covered the answer well. I would just like to add to what Wing has eluded to, and that is that no matter how much of a hot shot pilot you are, when you are flying manually, you are piling on the workload for the other pilot, who already has a long list of duties to keep him/her busy without having to monitor your manual flying very closely.

Manual flying is great fun, but there is a place and time for it and complete situational awareness and control always takes precedence to a bit of fun flying it manually. Flying it alone on the flight deck from FL190 as 707cmf experienced just should not happen unless an emergency requires it. It isn't safe.


User currently offlineSaab2000 From Switzerland, joined Jun 2001, 1610 posts, RR: 11
Reply 7, posted (10 years 6 months 4 weeks 9 hours ago) and read 4411 times:

We had a company policy which stated that if one pilot was not present in the flight deck it was prohibited to fly by hand. What happens if the pilot becomes incapacitated while flying by hand and there is nobody else around? Not a good thing.

Anyway, we did have a couple guys who enjoyed flying a lot by hand and basically that is OK, except, as CX Flyboy talks about, it also increases the workload of the Pilot Not Flying. I had to monitor these guys like hawks because, to be honest, they flew by hand to prove that they were good pilots, which proved to me at least that they were not very good at all. Well, they had 4 stripes and I did not, so I left it at that and they were not breaking the rules. But flying by hand in anything other than perfect weather is really not a very good idea in an airliner unless there is a fairly good reason for it, IMHO.

Just my $.02.



smrtrthnu
User currently offlineSevenHeavy From United Kingdom, joined Mar 2004, 1156 posts, RR: 10
Reply 8, posted (10 years 6 months 4 weeks 8 hours ago) and read 4405 times:

Thanks for all the replies, Great info!

Regards, SevenHeavy



So long 701, it was nice knowing you.
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 9, posted (10 years 6 months 4 weeks 8 hours ago) and read 4399 times:

Good answer Wing. The same things apply for the little bizjets as well. Every once in a while you'll still run into the "macho" type who says real pilots don't use autopilots, but fortunately those guys are getting rarer. Face it, in my opinion, there are times and places where you have simply no business hand-flying a high performance jet aircraft - big or small. For example, below 10,000' in VFR conditions on a beautiful weekend day in the LA Basin, or Phoenix area, or near any other big metropolitan area. It's times like those that you need every available eyeball looking for traffic and you have no business trying to hand-fly the airplane.

Jetguy


User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 10, posted (10 years 6 months 3 weeks 6 days 20 hours ago) and read 4306 times:

Hi Jetugy,

Once a UA captain told me that when there is an opportunity for them to hand-fly the airplane, they do it without the Flight Directors. I'm just wondering, how do they do this? Let's say you'll hand-fly below 10,000 feet and you have a STAR to follow, and without the flight director, how do they fly the profile accurately?

And a side note, I ahve no idea why they locked "My Dad" up... I wasn't in time to reply there. It's always very hurting to lose a loved one. My sincere condolences and my prayers are with you.

alvin



Boeing747 万岁!
User currently offlineWing From Turkey, joined Oct 2000, 1573 posts, RR: 24
Reply 11, posted (10 years 6 months 3 weeks 6 days 12 hours ago) and read 4269 times:

Mr BA,
Your question reminded me the first days of my big jet flying.As a young FO who started jet flying I was thinking "I'd rather loose an engine instead of loosing the flight directors".

Men has a tendency to get used to what is easy.Once you get used to hand fly with an easy reference infront of you(of course whatever FD's show you is dialed there by the other pilot)you never want to leave it.

But as your self esteem and experience grows you start flying more precise without the help of electronics.You try to reach to a level where you can fly your airplane with only one engine and two wings available even the captain is incapacitated.

The quicker you reach that level physically and knowledgewise the more comfortable you can sit in the cockpit.

Now is it posible to hand fly a STAR without FD's?Yes thats why we are there for,to fly it under any circumstance.Is it a wise thing to fly a STAR without it when you have all the technologic help available and working?Well you decide it under the light of answers given by the valuable contributers.Best Regards.WING



Widen your world
User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 12, posted (10 years 6 months 3 weeks 6 days 10 hours ago) and read 4254 times:

Hi Wing,  Smile

Thanks for the input. The UA captain who was in conversation withme told me that pilots are very used to flying with the reference of the FDs in front of them. He once went through a recurrent(?) training in the smimulators and of all the things the check captain turned off the FD in that case initiating a situation where the FDs failed and he did get lost for a while!




Boeing747 万岁!
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 13, posted (10 years 6 months 3 weeks 6 days 6 hours ago) and read 4209 times:

I believe you've gotten some good, valid answers here. They seem to echo my own experience. Just want to add a couple of things.

You might find earlier posts on exactly this topic if you search under "automation" or anything else like that that you can think of. I know I recall earlier threads that also had this topic.

I am not one of those use-the-damn-search-function people. This stuff is going to come up again and again - that is what internet forums are for! New people sign on with questions that are only "old" to those who've been here too long. When that happens to me I just ignore the thread. But if you want to read more, I know it is here somewhere.

Second, (as I posted on earlier threads but I can't find them either) at a lot of airlines we are expected to "select an appropriate level of automation." This can run the gamut from hand-flying without flight directors all the way through sitting back sipping our coffee and watching the magic stuff work.

I fly fully automated planes capable of flying an approach (once programmed) landing, tracking the centerline and applying its own brakes. Do I feel useless? No, like most of the guys I fly with, I will punch it off when I am ready to fly.

An airbus only gets half extension of the flight spoilers when the autopilot is engaged. If we get turned in closer than we expected, we may punch off the autopilot to get full speedbrake, then maneuver manually to a point where we can go back to normal. At that point we can re-engage the autopilot if we want to. Often we would just put the command bars back up and hand-fly the rest of it.

Most of us agree that some hand-flying is good for our proficiency. We joke that you can tell who has a checkride coming up by how much they hand fly.

Last, when I flew Boeings I never used CWS other than just to see how it worked. I just never felt that it added anything to the system. An airbus being hand-flown is rather like a Boeing in CWS.




Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineRyanair737 From , joined Dec 1969, posts, RR:
Reply 14, posted (10 years 6 months 3 weeks 6 days 3 hours ago) and read 4174 times:

I know CWS is a selection of autopilot, but how is it different from CMD mode? And when is it used?

Thanks
Ryanair737  Smile


User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 15, posted (10 years 6 months 3 weeks 6 days 3 hours ago) and read 4163 times:

In CMD the autopilot will fly the programmed modes, vertical speed, altitude hold, heading hold, tracking VOR or ILS etc. In CWS (control wheel steering) it just holds the attitude you place it in. It is sort of an advanced stability augmentation system. As I said, a lot like an A-320 being hand-flown.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineDC-10Tech From United States of America, joined Jun 2001, 298 posts, RR: 2
Reply 16, posted (10 years 6 months 3 weeks 4 days 22 hours ago) and read 4040 times:

The CWS mode is like a power assist. With the autopilot in CWS, the autopilot will only do what it senses the pilot doing. If the pilot pulls the yoke back, it will assist and hold for him. I demonstrate this to people on the aircraft by having them pull back on the yoke with no autopilot on. They will use both hands and need to pull firmly to get full up elevator deflection. Then, with the autopilot in CWS, I simply tell them to pull on the column with only one finger. They are able to pull gently with one finger and achieve full deflection. Its like power steering on demand!



Forums.AMTCentral.com
User currently offlineBarney Captain From United States of America, joined Nov 2001, 970 posts, RR: 13
Reply 17, posted (10 years 6 months 3 weeks 4 days 19 hours ago) and read 4011 times:

It's great to see how most other operators run their cockpits, but here at good ol' Southwest, we still do a lot of hand flying. We have no real policy guidance on when to engage the A/P, but most guys like myself, engage it out of 10k feet. On approach, I usually kick it off as soon as we get cleared for the visual approach, or if on an ILS, whenever the runway comes in to view. Interestingly, on the lowest visibility approaches we fly, the A/P must be disengaged and the A/C hand flown. That of course being the Cat III HUD ILS flown to 700 RVR.


...from the Banana Republic....
User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 18, posted (10 years 6 months 3 weeks 4 days 12 hours ago) and read 3951 times:

I think I'm missing something here. Which aircraft has the CWS and how do you disable or enable it?

Thanks  Smile



Boeing747 万岁!
User currently offlineRick767 From United Kingdom, joined Jan 2000, 2662 posts, RR: 51
Reply 19, posted (10 years 6 months 3 weeks 4 days 9 hours ago) and read 3912 times:

Take a look at this photo in 'large' mode:


View Large View Medium
Click here for bigger photo!

Photo © Julian Whitelaw



You will see the CWS buttons (CWS A and CWS B) below the two CMD buttons on the right of the glareshield, just left of the First Officers Course Selector, above the autopilot disengage bar.

As others have mentioned, the system is seldom used, and many operators (inclusing my former employer) elected not to have the system installed on their aircraft. We had it on some of our older 767s but I never recieved any training other than theoretical on it's use.

The two pictures below show a 757 flightdeck, one with CWS installed on the left and one without on the right. The buttons are in the same location below the CMD buttons, as with the 737:


View Large View Medium
Click here for bigger photo!

Photo © Tony Silgrim
View Large View Medium
Click here for bigger photo!

Photo © Tommy Mogren / Viking Slides




I used to love the smell of Jet-A in the morning...
User currently offlineDC-10Tech From United States of America, joined Jun 2001, 298 posts, RR: 2
Reply 20, posted (10 years 6 months 3 weeks 3 days 17 hours ago) and read 3810 times:

One use that some airlines train thier crews on is as a back up in case of severed control cables. In the rare even that the mechanical link to the flight controls may be severed (due to decompression, or whatever) the autopilot might still be available to fly the aircraft, since it is directly link to the actuators by wires (I'm talking non-FBW aircraft). I have an old UAL DC-10 training CD that actually teaches this.



Forums.AMTCentral.com
Top Of Page
Forum Index

Reply To This Topic Autopilot Disconnects On Commercial Jets
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...
Auto-pilot Landing On Commercial Airliners? posted Fri Oct 6 2006 17:26:23 by Jawed
Thrust Vectoring On Commercial Aircraft posted Tue Aug 1 2006 16:43:08 by Texfly101
Wing Condensation On Fighter Jets posted Sun Jul 30 2006 09:25:21 by Bruce
How Big Are The Overhead Bins On The E-Jets posted Thu Jul 6 2006 02:17:23 by Tangowhisky
High Speed Commercial Jets posted Thu Jun 15 2006 13:15:46 by NWDC10
Rnav On Older Jets? posted Tue Feb 7 2006 01:38:00 by Timz
Autopilot Use On ILS Approach posted Sat Sep 17 2005 07:19:39 by LPLAspotter
Types Of Circuit Breakers On Commericial Jets posted Mon May 30 2005 10:08:56 by HAWK21M
Emergency Exits On Biz Jets posted Tue Feb 15 2005 00:02:43 by Atomother
Dotted Box On SQ Jets? posted Fri Aug 6 2004 07:57:34 by UA777222

Sponsor Message:
Printer friendly format