Questions tagged [boeing-737]

A short- to medium-range twinjet narrow-body airliner, originally introduced in 1968. With over 10,500 aircraft delivered and over 4500 on order, the Boeing 737 is the most popular commercial jetliner in history.

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Why was the 737 main rudder servo valve’s vulnerability to causing uncommanded reversals never discovered in testing?

As was discovered during the NTSB investigation into the crash of USAir Flight 427, the design of the servo valve inside the main rudder power control unit (PCU) formerly used on 737 Original- and ...
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What is that little black thing tied to the vertical stabilizer? [duplicate]

I have seen this on all Boeing test planes, does this provide information on the planes performance?
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What are these five indicators at the front of the 737 passenger cabin?

As a passenger I noticed a set of five indicators on the ceiling at the front of the 737 passenger cabin. They are red, yellow (or white), blue, white, red. The red ones seem to be coupled together (...
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How does the B737's 'throttle offline' setting work?

I'm concerned about this article: Throttle online means that the crew can override the autothrottle logic, while Throttle offline means that the logic cannot be overridden. So for example - rejected ...
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Why did Boeing choose for a solution as aerodynamically invasive as MCAS to solve a much less safety related issue? [closed]

Why would Boeing, or anyone, ever jeopardize the aerodynamic integrity of an airliner, just to change the way a pilot feels the controls? The more I learn about it, the clearer it becomes that that is ...
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How can I know the manufacturer of the PFD (Primary Flight Display) of the current mainstream passenger aircraft?

I'm developing a computer vision software based on the photos of these PFD (Primary Flight Display). How can I know the manufacturer of these PFD of the current mainstream passenger aircraft: B737. ...
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Why does the KC-46 use two sensors for MCAS when the 737 Max doesn’t?

this article states The KC-46 has a two-sensor MCAS system, which “compares the two readings,” the Air Force said. I’m aware that the 737 uses two sensors and always has, but the computer reads ...
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Did A320 NEO need an equivalent to 737 MAX MCAS because of its bigger engines?

We read that MCAS on the Boeing 737 MAX was needed because of the new, bigger, heavier engines of the MAX compared to the previous 737 versions. The closest equivalent to MCAS on the Airbus A320 NEO ...
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What is MCAS trying to fix on B737 MAX?

New sources such as Seattle Times and Aviation Week provide a pretty good overlay of the MCAS function on B737 MAX. However, I'm unclear as to the issue that MCAS is attempting to fix. From what I can ...
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Why the need for the MCAS on the Boeing 737 Max 8? [duplicate]

Was there a problem with stalling on 737 jets before the 737 Max, if not then why is MCAS needed on the 737 Max 8.If it was a problem why did Boeing wait so long.
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Why not more Max 8 accidents?

Why did "only" two Max 8 accidents occur? Before the grounding, there must have been at least dozens but surely 100s if not 1000s of flights with this model. How come the vast majority of ...
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Would fitting a T-tail on the 737 Max make MCAS unnecessary?

This is pretty far out, so I just pose it as a question for notion or ideas, rather than conclusive answers. Considering the differences in flight characteristics between the Boeing 737 Max-8 and ...
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Who manufactured the 737 MAX flap track fairings?

I can't seem to find the information online, would anyone of you know where / by who the flap track fairing for the B737 MAX is produced?
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What would be the expected approximate ROD when descending at 250 kt IAS using LVL CHG at 10,000 ft, assuming a GW of 60t?

The question refers to a B737NG but I suppose most similarly sized airliners would show a similar ROD under the circumstances.
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What kind of problems can a flight have if passenger weight is miscalculated?

There was a widely reported news story about a TUI Boeing 737 flight, where a bug in reservations system caused 38 passenger on the flight to be allocated a 38kg standard weight as opposed to the ...
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What happens if the crew do not set a FLT ALT in the cabin pressurization panel and leave it at zero but AUTO is still selected?

On the 737NG, will the cabin maintain a lower altitude than the plane or will cabin altitude equal aircraft altitude? Will there be ANY cabin pressurization or none at all? When will the HORN sound? I ...
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Does the Autopilot switch to ALT ACQ mode at a fixed altitude difference from target altitude?

For example, if climbing (or descending for that matter) at 3500 fpm, will the AP switch to ALT ACQ mode at the same point it will as when climbing or descending with 1000 fpm? Or does the point of ...
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Is there a GPWS volume control in the audio control panel for the B737? [duplicate]

So, I was sitting in the front rows of an A320 and could obviously hear the AP disconnect. But I could not hear the GPWS altitude and RETARD callouts. I assume this is because the pilots set the GPWS ...
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Is there a cockpit indication if the B737 flap load relief is not working properly?

On a 737, does the pilot get any cockpit indication that his Flap Load Relief is not working properly? Say for instance due to a Flap Lever Position Switch failure?
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What is the maximum wind speed a Boeing 737-800 can deal with during takeoff and landing?

I'd like to know how safe the Boeing 737-800 is during takeoff and landing when it's windy. What are the maximum wind speeds for cases of tail, head and cross winds? EDIT I've found this resource ...
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What are the random, differently-coloured rectangular patches on the top of this Boeing 737's fuselage?

The top section of this green-painted Boeing 737's fuselage was slightly faded and I noticed a few dark-green, rectangular patches on its top. They look like patch kits on a bicycle tyre's inner tube. ...
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What programming language(s) is Boeing's MCAS written in?

What language is Boeing's MCAS written in? Thanks
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How controllable is the 737 in single-engine manual-reversion flight? Is it controllably landable (or go-around-able) in this condition?

The 737 is practically the only civilian jetliner still in production1 to have provisions for flight-control manual reversion; in the event of a total failure of the A and B hydraulic systems, the 737’...
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When does the FMS in the 737NG switch to approach mode?

I fly a B737-800, and we talk about when the FMS enters "Approach mode". At this point, the FMS will command the Vref (plus additive) at the appropriate flap setting. This is helpful to know ...
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Why are the 737's variable-speed generator drives so unreliable?

The 737 Classic has two different possible styles of engine-driven generators, distinguished by the generator's drive mechanism: the constant-speed drive (CSD) and the variable-speed constant-...
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Why do the 737-100's JT8Ds, and no others, have suck-in doors?

Of the various use cases of the Pratt & Whitney JT8D (the most-produced low-bypass turbofan in history, and the second-most-produced turbofan of any description1), those installed on the 737-100 ...
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What would cause an abrupt increase in engine noise after takeoff on the Boeing 737-800?

I flew last week on a Boeing 737-800, I was in row 7, so just in-front of the wings. I know from experience that there is a significant difference in engine noise from the front to the rear of the ...
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What are these lines on the nose of a Boeing 737?

What are these lines on the radome? You can also see them here: What are they and what is their function? Source: AviaFilms
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How are the 737’s elevator and aileron cables attached to their control tabs without impeding the control surfaces’ motion under hydraulic power?

The 737 (all versions thereof) is one of the few jetliners still in production to have any manual-reversion capability for its flight controls in the event of the loss of all hydraulic systems. If ...
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Why does the 737 Original have an explicit hydraulic-quantity indicator for only the A hydraulic system?

The 737 (Original, Classic, NG, and MAX) has two primary hydraulic systems (A and B),1 which provide power to the aircraft’s flight controls and other aircraft components (like the wheelbrakes, ...
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Is using a DERATE for Takeoff actually reducing the power of the engine?

When one chooses a DERATE for takeoff (TO-1 or TO-2 in the case of a B737), does the system actually reduce the available thrust of the engines, or is it computing a N1 that corresponds to the reduced ...
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What is a (rough) rule of thumb for calculating fuel consumption in a modern jet airliner like Boeing 737 - 300?

I'm wondering what would be a rough rule of thumb for calculating the fuel consumption of a modern airliner like a Boeing 737 - 300. I am not asking for anything from the plane's manual or even a ...
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Referring to the B737NG, at what point (height) does a TOGA revert to LVL CHG after the takeoff?

If one takes off with HDG SEL armed and no vertical mode (like VNAV) armed, at what height (AGL) will the vertical mode switch from TOGA to LVL CHG, and what will be the IAS applied? Also, why isn't ...
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Which FARs does the Boeing 737 MAX conform to with respect to turbulence?

Based on this question/answer it seems that the FARs in relation to turbulence handling have been updated several times over the years. Does the Boeing 737 MAX conform to the latest FARs or to the ...
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What is the takeoff thrust of a CFM56 engine?

So, to be more clear I currently have an assignment about the Boeing 737-800. I have to find out the total takeoff distance of the aircraft. I'm using Anderson's book " Aircraft Performance and ...
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How to deal with both a speed and an altitude crossing restriction while in VNAV PTH descent (Boeing 737NG)?

Suppose you are in VNAV PTH descent and are approaching the IAF for your Approach, The IAF has both an altitude crossing restriction and a speed restriction. Assume that your VNAV PTH descent is at ...
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What is the ALT INTV on the 737's autopilot?

So, I was watching a quick tutorial on the FMC on YouTube. The FMC somehow had a 5000 ft restriction, and the guy got clearance to go higher up, and he set his altitude on the AP panel, and he pressed ...
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Is it possible to define a “good landing” in terms of pitch angle and vertical speed?

Is there a specific combination of pitch angle and vertical speed at touchdown that would be usually be considered a "good landing" in a B737NG?
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Is AA actually flying the 737 MAX?

In flightradar24 I only see 737 MAX flying from Gol Airlines and Aeromexico, but none from AA. Is American actually flying the 737 MAX or is FlightRadar24 reporting aircraft types wrong ? I also see a ...
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What does “transition of glideslope intercept waypoint” mean in the 737 FCOM?

In the Boeing 737NG FCOM, I've read this statement: VNAV mode is terminated by any one of the following: selecting another pitch mode glideslope capture reaching end of LNAV route transition of ...
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Why did Boeing not create a new 737 instead of just upgrading the old model?

This documentary claims that James McNerney - Boeing's first CEO without a background in aviation, made the decision to upgrade the 737 series to 737 MAX instead of developing a new model. Is this ...
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What is the technique or procedure to disable/disengage the MCAS on Boeing 737 Max 8 & 9 Aircraft?

What is the technique or procedure to disable the MCAS and manually fly the Boeing 737 MAX 8/9 Aircraft? To clarify my question, what I'm asking is can the pilot disengage the MCAS and if so, how do ...
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Is the descent performance of the PMDG 737-800 accurate?

I often fly the PMDG 737-800 (with winglets) in my home simulator and most of the time, I find it hard to slow the aircraft down for landing when I descend. Most of the time, I need to deploy the ...
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What are the conditions under which one would normally switch on the Engine and the Wing Anti Ice?

As per the title. But I would also like to know if both (Engine and Wing) are turned on at the same time or if different conditions dictate the use of each one. I am specifically interested in the ...
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In the B737NG, is the CTR tank fuel the first to be pumped when there is fuel in all tanks?

In a B737NG, assuming you have fuel in all tanks, Wings and Center, and that all pump switches are ON, will the fuel from the CTR tank be the first to be pumped, despite all Fuel pump switches being ...
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Is the B737NG AoA indicator a “normalized” indicator?

Is the B737NG AoA indicator, when/if it exists, an indicator of "normalized" AoA, or does it indicate the actual AoA measured?
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Are 737 pilots required to train in manual-reversion flight?

All jetliners prior to about 1970 had flight controls that could, if need be, be manually operated without the use of any hydraulics: Some, such as the DC-9, had manual flight controls with hydraulic ...
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What is the maximum take off climb angle of a Boeing 737 MAX?

This video is making its rounds on social media claiming to show a 90 degree vertical take off: One can not tell from the video alone what the angle is. Does anyone have a third party reference for ...
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Why doesn’t the A320 family suffer from the same design constraints regarding engine placement/landing gear length as the Boeing 737 family?

This answer gives a pretty good description about the design issues which lead to the problems of the Boeing 737 Max (basically the same as in a video I watched a while ago): The landing gear of the ...
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Does a VNAV PTH descent need the Forecast Descent winds?

If VNAV PTH, contrary to VNAV SPD, maintains a given path angle, depending on the CI chosen, and not a given Speed, then in my mind winds shouldn't affect it, since they would only cause the Vertical ...

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