With SU2 rounding the bend I thought it would be nice if I started a post with some common questions on NG operations-behaviors etc. Anyone with knowledge and feel like chiming in please feel free to add here, i'll start.QUESTION: What MODES are engaged when you engage the Autopilot (CMD button) in takeoff mode (TOGA is pushed) if no modes were armed on the takeoff? ANSWER: If you engage an autopilot while in takeoff mode, LVL CH is automatically engage for pitch. Wings level is commanded for roll prior to autpilot engagement when pushing TOGA.QUESTION: When does the AFDS leave the takeoff mode? Answer: The autoflight system goes out of the takeoff mode when an autopilot is selected or a pitch mode is engaged.QUESTION: What SPEED do I set on in the MCP speed window for takeoff? ANSWER: You ALWAYS set V2. Not V2+ 15-20 etc, it is ALWAYS V2.QUESTION: When can I engage LNAV? ANSWER: You can select ARM LNAV while on the ground. A ROLL mode can be engaged at 400 AGL.QUESTION: When can I select VNAV? ANSWER: You can select VNAV at 400 AGL although one should fully retract their flaps before doing so. QUESTION: What happens if you have a DIFFERENT altitude set on the MCP altitude window than what is set for your cruise altitude on the FMC? ANSWER: This will cause the aircraft to temporary level off at the MCP altitude. The FMA will display FMC SPD and ALT HOLD, the MCP SPD window will stay blank. Reset the MCP altitude and engage VNAV to continue your climb.QUESTION: What is the difference between a VNAV PATH DEScent and VNAV SPEED DEScent? ANSWER: In a PATH DESCent the aircraft will maintain the PATH without concern for the speed, it is the pilot's job to control his speed during the DEScent. For the SPD DEScent, the aircraft will maintain (i.e. PITCH) the target SPEED selected on the DESCent page without regards to the PATH. The pilot can use the speedbrakes or throttle to try to maintain the path if desired. Also, in a SPEED DESCent the aircraft will honor all waypoint restrictions by temporary level off until it passes the waypoint's original point on the path and resume DEScent.QUESTION: What happens in a DEScent if the aircraft overspeeds? ANSWER: The aircraft will be able to stay in VNAV until 1 knot prior to the barber poll, at which time the AFDS reverts to LVL CH.QUESTION: I notice in some screenshots on takeoffs that there are GREEN V speeds on the pilot's flight display, how do I get those to appear? ANSWER: V speeds will show after you complete pre flight on the FMC. On the PERF INIT page, fill in all the required data i.e all the BOXES are the required entries. To make this simple, you can select the TOP LEFT LINE SELECT KEY (LSK) next to your GROSS WEIGHT and it will generate the correct weights. Also fill in the TAKEOFF page with your flap selection. You can also LINE SELECT the RIGHT side LSKs next to the v speeds to automatically generated V speeds on the page. Set the V2 speed on the MCP speed window. This is handy when you do not want to program a complete route but do desire the correct takeoff speeds.QUESTION: How do I preform a DIR TO? ANSWER: Bring up the LEGS page. The very first waypoint is the active waypoint. If you desire to go direct to a waypoint already in your route, locate the waypoint on the legs page and *click* the LEFT LSK which will place the waypoint into the FMC's scratchpad OR type it into the scratchpad AND put it OVER the FIRST waypoint (TOP LEFT LSK)- the active waypoint and push EXECU. All the waypoints that were BETWEEN the original waypoint and the new DIR TO waypoint are removed from the route.If you need to preform a DIR TO to a waypoint or fix NOT already on your route, this action will create a ROUTE DISCONTINUINTY. Remember that any time you ADD or REMOVE waypoints from your route it will create a ROUTE DISCONTINUINTY. What this is is a break in your route that you will need to connect. So just line select (LEFT LSK) the NEXT waypoint listed after the DISCon and place it in the DISCON boxes and push EXECU. More coming ;) [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

>QUESTION: What MODES are engaged when you engage the>Autopilot (CMD button) in takeoff mode (TOGA is pushed) if no>modes were armed on the takeoff?>> ANSWER: If you engage an autopilot while in takeoff>mode, LVL CH is automatically engage for pitch. Wings level is>commanded for roll prior to autpilot engagement when pushing>TOGA.>I have a question for you Randy...What happens if you overshoot v2 and hit, say, v2+30. When LVL CHG engages does it put the current IAS in the window or will it revert to v2+20 and drastically increase pitch to slow down?My intuition says it will hold the greater of v2+20 or current IAS.Interested to hear what's correct.Thanks!Jeff

Ah good question! It changes to V2 + 20. Remember that procedure will differ between airlines. Also, if you touch the MCP speed button it will jump to V2 + 20 prior to AP engagement. Most pilots fly V2+20-40 depending. So you can always speed up FIRST to retract the flaps etc and then engage. Many ways to do this ;) Cheers, [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

So, all hand flying aside...If I take off and trim out for initial climb at v2+30 and engage the autopilot at 400AGL. LVL CHG will engage and automatically command v2+20? If yes, and I am trimmed at, say, 17 degrees when I do this, then the plane will most likely pitch up above 20 degrees to slow the plane down to v2+20 and then pitch back down to around 17 degrees to maintain it?Seems like I'll be send the FO back to collect the barf bags... ;)BTW, this CWS stuff sounds really awesome and could make this whole though process irrelevant. Just point and shoot!Take care,Jeff

Well I would ask Boeing why but it IS the way it does it. I would state that if the pilot knew this was the case, he would work around it by either pitching V2 +20 or holding off on LVL CH until he has accelerated. LVL CH has a nasty habit on the real NG for pitching, remember that the A/P does not take PAX comfort into account, that's the pilot's job ;)...[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

Agreed ;)Thanks for the info!Jeff

"QUESTION: When can I select VNAV?ANSWER: You can select VNAV at 400 AGL although one should fully retract their flaps before doing so."No doubt it differs from airline to airline, however, the AOM I have says this...VNAV Pitch ModeThe use of TO/GA mode to flap retraction altitude and VNAV for flap retraction and climb is a method of managing the AFDS for takeoff. To use this mode, at flap retraction altitude with at least V2 + 15 knots and accelerating, the PF calls

QUESTION: Can you tell me on how to preform a HOLD with the FMC? ANSWER: On the CDU push the HOLD button. At the bottom LEFT there are BOXES to which you can LINE SELECT or TYPE a waypoint into the scratchpad and select the BOXES PROMPT and hit EXECU. You can also push PPOS PROMPT (RIGHT LSK 6) and hold at your present position.QUESTION: What are the ways one can EXIT the HOLD? ANSWER: There are a couple of ways to accomplish this. One way is simply to push EXIT HOLD prompt on the HOLD page. This will create a DIR TO to the HOLD waypoint thence route. You can also preform a DIR TO to any active waypoint on the LEGS page to exit. QUESTION: What is CWS? ANSWER: CWS=Control Wheel Steering. CWS has 2 MODES, CWS P (PITCH) and CWS R (ROLL). It enables the pilot flying to make control inputs very much like an Airbus control stick, it will hold pitch + roll modes set by the pilot. So if you move the controls to a pitch of 12 degrees it will HOLD this input. Same goes for roll. If you select a roll mode less than 6 degress, the aircraft will roll wings level. CWS can be selected on the MCP. It will also automatically engage in certain situations. If you are in CMD with ALT HOLD or VNAV-LNAV or HDG SEL and apply pressure (i.e hold the controls in a pitch direction or roll direction) CWS will engage.[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

QUESTION: How can I change my CRZ ALTitude without going out of VNAV? ANSWER: Display the CRZ page on the FMC. Dial in a NEW altitude on the MCP altitude window, this will automatically place the new altitude into the CDU's scratpad (Note: this will only place it here with the CRZ page displayed) select it into the CRZ's page Cruise alt line and hit EXECU. Whether you are climbing OR descending to a new cruise altitude, the CRZ page's title will change to ACT CRZ CLIMB or DESCENT.QUESTION: I have seen screenshots with a GREEN circle with distance displayed on the ND (Navigation Display), how do I draw one on mine? ANSWER: You can do this by creating a FIX. An example of one I use is for a departure (MOONY rwy 12R) out of KSJC where I need to turn LEFT at 6.8 DME to a 090 heading and would like a visual on the ND. Bring up the FIX page on the CDU. Enter the fix (in this case I enter SJC) into 1 Left LSK. Side note here, after inputting SJC I was presented with more than one fix named SJC, the FIRST one displayed on the list is always the closest to your position. Now I have a green circle but it is small and contains no distance. So I type my runway heading and distance for the fix into the scratchpad like this 123/6.8 and select the 2nd left LSK. I now have it displayed correctly.http://forums.avsim.net/user_files/50094.jpg[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

QUESTION: What is this see-dubbya-ess(CWS) thing I keep hearing about? ANSWER: It stands for Control Wheel Steering. It in essense allows the pilot to manually fly the airplane, with autopilot help. For instance, if the pilot wants to roll the plane to the left for a 180 turn, the pilot can engage CWS, and then roll the plane to the desired bank. The pilot can then release the control column and the plane will keep the bank and pitch levels that the pilot had used.

Randy, I am finding this question/answer stuff really useful. Thank you.Can I just verify that ALL this info is 'pre SU2'. Clearly, you have access to the infamous 'SU2' and I didn't want this old mind muddled by a mix here.Appreciate your continued support of this product. It is good.RegardsJock McIntyre Melbourne, Australia

Yes sir, for SU2 mostly ;). [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

I have a question about the FIX function. The other day I wanted to do a trans atlantic route and so I looked up the routes for the day. I was going out of KJFK to EGLL, and along the route I had to insert 4 fixes. The thing was, I only had the coordinates for the fixes, they can't be found in the FMC, so I was unable to do this...any thoughts?Mikkel

>So, all hand flying aside...>>If I take off and trim out for initial climb at v2+30 and>engage the autopilot at 400AGL. LVL CHG will engage and>automatically command v2+20? >>If yes, and I am trimmed at, say, 17 degrees when I do this,>then the plane will most likely pitch up above 20 degrees to>slow the plane down to v2+20 and then pitch back down to>around 17 degrees to maintain it?>>Seems like I'll be send the FO back to collect the barf>bags... ;)>>BTW, this CWS stuff sounds really awesome and could make this>whole though process irrelevant. Just point and shoot!>>Take care,>>JeffA 737NG pilot told me that when you are not quit heavy and you try to follow V2+20, you have a (very) high pitch. So what they do is flying V2 + 30 or 40 or so. When engaging the Auto Pilot, the MCP speed is automatically set to the current speed (so it could be V2+40, not V2+20. depends on the current speed)DONT RELEASE SU2 YET, ASK BOEING :-lol

Well, that was my thought and the more logical approach. But, Randy is saying that this is not the case and that, when the autopilot is engaged, it will automatically follow v2+20 and not the greater of current IAS or v2+20.Any further clarification?Jeff