Hi, I was making an approach (B737-800) following the guidance correctly, I was at the FAF fix altitude, then I set the minimum altitude and followed the VNAV path/LNAV etc. However, when I was descending and tried to set the missed approach altitude, the aircraft strangely canceled the decision completely, even though it was supposed to continue the VNAV path. Did I do something wrong?
Boeing Rnav approach question
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- Official Post
Did you use vnav or the approach mode?
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Did you use vnav or the approach mode?
Approach mode is only for Airbus no? In Boeing i use the Vnav in Rnav operations
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Hi, I was making an approach (B737-800) following the guidance correctly, I was at the FAF fix altitude, then I set the minimum altitude and followed the VNAV path/LNAV etc. However, when I was descending and tried to set the missed approach altitude, the aircraft strangely canceled the decision completely, even though it was supposed to continue the VNAV path. Did I do something wrong?
What exactly were you trying to do? Did you attempt a precise RNAV approach with a safe landing, or did you abort the landing and initiate a missed approach procedure?
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Hi, I was making an approach (B737-800) following the guidance correctly, I was at the FAF fix altitude, then I set the minimum altitude and followed the VNAV path/LNAV etc. However, when I was descending and tried to set the missed approach altitude, the aircraft strangely canceled the decision completely, even though it was supposed to continue the VNAV path. Did I do something wrong?
In RNAV approaches, the Boeing 737-800 automatically creates a glide path on the PFD, very similar to an ILS. This indication remains on the PFD for almost the entire flight when VNAV and LNAV modes are activated. As you approach the destination airport, this glide path indication remains on the PFD and will initiate an automatic descent as you approach this path. Once you reach the minimum FAF altitude, observe the descending glide path indicator, and before reaching the final waypoint, engage the autopilot's approach mode (APP). The aircraft will then initiate an automatic descent upon reaching the glide path created by the activated VNAV and LNAV modes. It is mandatory that both VNAV and LNAV modes are activated, as they together create this descent path, allowing the approach mode to automatically descend the aircraft to the decision altitude where you can disengage the autopilot and perform a visual and manual landing.
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Hi, I was making an approach (B737-800) following the guidance correctly, I was at the FAF fix altitude, then I set the minimum altitude and followed the VNAV path/LNAV etc. However, when I was descending and tried to set the missed approach altitude, the aircraft strangely canceled the decision completely, even though it was supposed to continue the VNAV path. Did I do something wrong?
I had this with A350 but couldn't reproduce it, exact same thing, descending below the FAF, set missed approach, aircraft should follow the VNAV path, but it wanted to climb to the missed approach altitude.
It's been a long time since I've flown a Boeing in the sim, but on the Airbus, the PFD alt window turns grey, which tells you its ok to set the missed approach altitude.
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I had this with A350 but couldn't reproduce it, exact same thing, descending below the FAF, set missed approach, aircraft should follow the VNAV path, but it wanted to climb to the missed approach altitude.
It's been a long time since I've flown a Boeing in the sim, but on the Airbus, the PFD alt window turns grey, which tells you its ok to set the missed approach altitude.
• I put the RNAV approach on the PFD, arrive a little before the FAF altitude with landing configuration (make sure the Flight Director is active!)
• Then check if V/DEV is active on the PFD and that you are neither too high nor too low (like ILS)
• Then set the minimum altitude for the aircraft to begin the descent, click APPR on the AP panel, and after a certain altitude below, set the missed approach altitude.
And make your butter landing!
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In RNAV approaches, the Boeing 737-800 automatically creates a glide path on the PFD, very similar to an ILS. This indication remains on the PFD for almost the entire flight when VNAV and LNAV modes are activated. As you approach the destination airport, this glide path indication remains on the PFD and will initiate an automatic descent as you approach this path. Once you reach the minimum FAF altitude, observe the descending glide path indicator, and before reaching the final waypoint, engage the autopilot's approach mode (APP). The aircraft will then initiate an automatic descent upon reaching the glide path created by the activated VNAV and LNAV modes. It is mandatory that both VNAV and LNAV modes are activated, as they together create this descent path, allowing the approach mode to automatically descend the aircraft to the decision altitude where you can disengage the autopilot and perform a visual and manual landing.
Hi, the problem I noticed is that you said you click on the app, but that's for ILS operations, not Rnav/Rnp. When you do it correctly, using only Vnav/Lnav and capturing the glide slope, you enter the missed approach altitude. However, when you do this on a B737, it starts a climb, even though in real life the altitude is selected but doesn't actually climb to it, unlike on Airbuses where the altitude remains white and isn't used.
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Is it normal for the autopilot on the Boeing 737/800 to automatically disengage shortly before landing? Shouldn't that be the pilot's responsibility? Now I'm a bit confused.
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- Official Post
Is it normal for the autopilot on the Boeing 737/800 to automatically disengage shortly before landing? Shouldn't that be the pilot's responsibility? Now I'm a bit confused.
Yes, that is the difference between the autopilot with or without rollout capabilities. Both versions exist in the real world. Our 737 Max 9 behaves differently than the -800 or -900ER because we equipped it with the more capable autoland system. The 737-800 and -900ER autopilot does not arm the "ROLLOUT" lateral mode prior to landing, indicating that it's not capable of steering the nose wheel and maintaining the runway centerline, whilst the 737 MAX aircraft does arm the mode and is capable of doing this in our sim.
