62
votes
How are fighter jets allowed to be flown by one pilot even with maximum take off weights exceeding 12,500 lb?
There are actually two different answers to this question.
First, your information that all airplanes over 12,500 lbs. must have two pilots is outdated. Now, while most such planes require two pilots (...
- 12.8k
57
votes
Accepted
Is it possible to install a bike rack on a Cessna 172?
Is it practically possible to do that? Is it okay in terms of
weight, CG?
Bikes (depending on make and model) are not all that heavy and in this picture they are more or less center mass and would ...
- 102k
43
votes
Accepted
Do all aircraft carry depleted uranium as counterweights?
From my research, it looks like about 0.1% of all aircraft carry depleted uranium counterweights.
The Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials (NUREG-1717), ...
- 5,801
41
votes
Accepted
Why is this plane struggling to gain altitude?
According to the video's information:
EMB-721 Sertanejo heavy and insane takeoff in Carlos Prates
This is
"EMB-721 Sertanejo heavy and insane takeoff in Carlos Prates.
Full fuel, 6 on board plus ...
- 560
35
votes
Accepted
Can an airline reject a passenger for being overweight?
Yes. If carriage of said person on a particular flight would cause the aircraft to be overloaded or outside of its CG envelope, the airline has full right to refuse them passage for safety reasons. ...
- 75k
34
votes
Is it possible to install a bike rack on a Cessna 172?
Just eyeballing your image, the CG looks OK, and it's possible to put that much weight into the interior of the plane just fine, so the weight is OK.
The aerodynamics on the other hand - yeah, no. ...
- 6,989
31
votes
Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?
It would be possible to design a system that computes an airplane's weight and C of G from the landing gear load in real time, either by incorporating load cells into the gear legs, or measuring ...
- 136k
28
votes
Accepted
What kind of problems can a flight have if passenger weight is miscalculated?
In general, an incorrect takeoff weight can have serious consequences for an airliner, especially when the actual TOW is close to the RTOW (regulated takeoff weight, see e.g. this question: What is ...
- 58.3k
27
votes
Why is there a maximum landing weight limit?
At the instant of touchdown, any vertical kinetic energy the plane possesses must be absorbed by the landing gear, which thereafter must bear the entire weight of the plane. That kinetic energy ...
- 22.2k
23
votes
What kind of problems can a flight have if passenger weight is miscalculated?
For "what kinds of problems can appear", there's the case of Air Midwest Flight 5481, which crashed on takeoff partly due to a miscalculation of passenger weight. In addition to needing ...
- 1,722
23
votes
Accepted
Is the Centre of Gravity moved by an aircraft travelling at “High Speeds”?
Changing the aerodynamic forces on any part of the aircraft CANNOT change the distribution of mass within the aircraft structure. The center of mass, (AKA center of gravity) can ONLY be changed by ...
- 6,175
22
votes
Is it okay to take off with weight more than the POH max gross weight?
Can you take off over gross weight? Yes, it's possible on any airplane, dependent on how far over the weight limit you are, the density altitude, how much runway you have, what obstacles are in the ...
- 54.4k
21
votes
What would happen if a plane lost half of its weight instantly?
In steady flight, the lift $L$ generated by the wings equals the loaded weight so that there is no vertical acceleration. Thus, the lift just before the bomb is dropped is
$$
L = m_1g = 245\,250 \;\...
- 543
20
votes
What would happen if a plane lost half of its weight instantly?
The A7E Corsair had an empty weight of around 19,000 pounds. Its fuel load was 10,500 pounds, and with six armed 2,000 pound MK84 general purpose bombs hung under the wing it had a total weight of ...
- 4,318
20
votes
Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?
It's not only possible, it's been done on military transports and some cargo aircraft.
However, one still needs to know the aircraft's mass (not weight) prior to takeoff. Gear-mounted strain sensors ...
- 30.1k
17
votes
What does %MAC mean?
%MAC (Percent Mean Aerodynamic Chord) is a mathematical calculation that shows where the center of gravity is over the wing. The calculations is rather straight forward and the generic formula is the ...
- 13k
17
votes
Why would a plane perform 360° turns to balance fuel on the ground?
They probably had a fuel imbalance that was marginally outside the limit for takeoff, and perhaps the powered fuel transfer system was unserviceable and was deferred. Typically there is a gravity ...
- 136k
17
votes
Accepted
Why is there a maximum landing weight limit?
Maximum landing weight (MLW) limit exists primarily to cater for approach climb performance requirements (i.e. go-around requirement). As per 14CFR 25.1001: if the aircraft does not have a fuel ...
- 11.1k
17
votes
Is the Centre of Gravity moved by an aircraft travelling at “High Speeds”?
The author of the book makes a correct introduction: "..movement of the centre of gravity is due to a change in weight. The distribution of the aircraft’s weight can change for three reasons"...
- 62.9k
16
votes
Can an airline reject a passenger for being overweight?
Airlines have rejected passengers for their size, perhaps more than their weight, specifically for being unable to fit into a passenger seat.
There appears to be some debate as to whether this ...
- 17.8k
15
votes
What is the weight that is used to balance an aircraft called?
747s in everyday operation typically use fuel for ballast when needed. Ballast fuel is considered to be part of the zero fuel weight and you are not allowed to burn it, although obviously if you were ...
- 39.2k
15
votes
Can an airline reject a passenger for being overweight?
When the aircraft is going to be overweight, then yes, the airline can only take what weight the performance numbers will support. That's somewhat uncommon, but it can defintely happen when takeoff ...
- 53.6k
15
votes
How do handling characteristics depend on flying with a full vs. an empty tank?
All aircraft are subject to performance changes due to fuel burn, and since weight, lift, thrust and drag are all tied together for every aircraft in the same way the changes scale nicely. Let's look ...
- 102k
14
votes
Why is this plane struggling to gain altitude?
Looks overloaded for the temperature/altitude conditions. With all the yapping and chattering, it sounds like the cabin was full. Once out ground effect, its rate of climb appears to have been around ...
- 136k
14
votes
Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?
If I'm right about this being Midwest 5481 the incorrect calculation of Centre of Gravity was not the full cause of the accident.
Most, of not all, accidents are caused by a series of events - what is ...
- 35.7k
13
votes
How do VTOL aircraft like the V-22 Osprey not tilt?
If you think about it, your question applies in exactly the same way to a conventional helicopter. You might expect that it would pitch nose-down if the weight is forward, and nose-up if the weight is ...
- 12.7k
13
votes
Accepted
How do engineers make sure UAV don't land on their front propeller?
Due to center of gravity limitations, it would be impossible for any type of aircraft to be loaded so that the front became the heaviest part. The aircraft would not be able to fly.
These UAVs are ...
- 37.9k
13
votes
Accepted
Why don't airports have weigh stations to prevent overweight takeoffs?
Aircraft are heavy.
Really, quite heavy.
An Airbus A340, depending on type, has a maximum takeoff weight (MTOW) of up to 380,000 kg.
A Boeing 747, again depending on type, can have a maximum ...
- 6,984
12
votes
What is the weight that is used to balance an aircraft called?
I am pretty sure you are thinking of ballast. These kinds of weights are used aircraft and in many other types of vehicles as well, particularly in ships, to maintain proper balance.
- 12k
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