Flying overweight

[Tantalum]

Last message.. then I'm done spamming this thread for a bit

on't forget that 2.8g has to multiplied by the weight to get the total force acting on the structure. 2.8g is the limit when at max weight

Right but these structural exercises are assuming the wing is capable of lifting that. To me it's like arguing that a hot air balloon's envelope will fail if you put too many people in the basket. As is with the balloon, it just won't rise, or climb as well. The wing, assuming all else is equal, can only generate so much lift, especially if staying under V(a)

Give it a bigger engine or dive go fast sure, if you can generate the airspeed needed to maintain lift.. but if I load a PA-28 up to 500 lbs over gross it's either (A) not going to take off or (B) not climb well. The wing's structure (so to speak) will have no idea that it's trying to carry more when going 75 knots. It's going to feel that same sub V(a) lifting force whether it's trying to lift 2,400 lbs or 240,000 lbs. It can only generate X amount of lift.


Either that or I'm thinking about this all wrong

 

[EdFred]

I dont think I'm getting off the ground at 2x gross weight. Conrad went at 60% over my model and and 33% over the later model which used the same spar and, from what I read, barely climbed. I I doubt I'm going to be able to fly at Double my gross weight and do any maneuver that's going to get me to 11,000 lb of force on the wing

 

[genna]

but personally if I'm going to need that much gas once a year, or less, then ….

You are not everyone. Putting 10g over the standard capacity in a M20K allows for 2 smaller people, bags, and an extra 45 min flight which may make a difference if you are flying to a beach airport with no services (very common around east coast) I’d literally use that on almost all my flights

 

[geezer]

Real life and a Mooney. Shared ownership. One owner made fairly frequent trips from Washington DC to Texas, alone, for a single day there. Luggage, trifling weight. 2 inch thick brief case, trivial weight. No warm clothes for the flight, high altitude cruise, but used the heater. Full tanks every time, no weight problems. Long, efficient cruises at near oxygen altitudes, few refuel stops.

That is a mission that conveniently makes use of all the fuel capacity.

Same Money, different mission, 4 adults, short day trip. Half full of fuel in main tanks. Overall weight about gross, lifted off in less than 2,000 feet with out a stall warning, and rapid climb to the filed altitude. Added fuel at the destination for the return trip.

I was a passenger on the second flight and another later one with 2 passengers, but not the long, full fuel ones. Very versatile plane.

 

[Mxfarm]

agreed

Are we thinking max gust loading is a structural issue while over gross weight?....it's certified to 6G's.

Keep your speed up and if you are able to climb all is good ....it will stall slightly higher with less control authority.

Flying is not the concern.....structurally, it's the carrier deck landing on an immediate return to landing that concerns me.

 

[David Megginson]

I'm a fairly new private pilot.

During training, and my flying afterwards I've always made my W&B and have always flown inside weight and cg limits.

How is that there are airplanes that can barely take a person when full of fuel? I'm looking at a Mooney M20k, with extended fuel tanks, that with full fuel it is just 170lb under MTOW.

Then in this 170lb you need to fit backpack, pilots clothes and pilots own weight.

I'm sure that an airplane like this most likely was never flown full of fuel or it has exceeded it's MTOW.

So, my silly question is: what's the deal with fyling heavier than MTOW? Apart from the fact that is ilegal...

As long as a CG is within limits, flying a 2900 lb airplane with a 200lb overweight, is that risky? Does people sometimes take off above max to weight?

Ferry permits often allow takeoff overweight, but they come with strict restrictions (including no non-crew passengers, from what I understand).

You're not professional ferry pilot. Just don't do it. On a hot summer day, my Piper PA-28-161 takes forever to start climbing after takeoff even at its legal max gross weight of 2,400 lb -- I have to get it bang on Vy and then wait a long time before I see an acceptable climb on the VSI. If you're overweight, you might not have the margin to clear the trees if you hit downdraft right after takeoff.

Even close to max gross weight, a new pilot is at serious risk: during training, solo or with an instructor, the picture out the window had the nose way up and the horizon down below the panel; when the newly-licensed pilot loads that same rental C172 right up to max gross with family and baggage for a summer vacation, the plane isn't going to look like it's climbing at all at Vy -- the horizon will seem to be almost in the middle of the windshield -- and when they pull back to try to get the nose up to where they're used to seeing it, that's when one of those fatal summer stall-spin accidents happens.

 

[FlyingTiger]

Interesting thread considering we just passed the 20th anniversary of the plane crash that killed Aaliyah and 8 others. Pilot was a real piece of work.

Investigation determined that when the aircraft (CESSNA 402) attempted to depart, it was over its maximum takeoff weight by 700 pounds (320 kg) and had one more passenger than it was certified to carry. An informational report issued by the National Transportation Safety Board (NTSB) stated, "The airplane was seen lifting off the runway, and then nose down, impacting in a marsh on the south side of the departure end of runway 27."It indicated that pilot Morales was not approved to fly the aircraft. Morales had falsely obtained his FAAlicense by showing logs of hundreds of flight hours he had never flown. He may also have falsified the number of hours he had flown to get the job with his employer, Blackhawk International Airways. Additionally, Morales' toxicology report revealed traces of cocaine and alcohol in his system. The NTSB reported that the maximum allowed gross weight of the aircraft was "substantially exceeded" and that the center of gravity was positioned beyond its rear limit.

 

[CaptainXap]

I'm a fairly new private pilot.
How is that there are airplanes that can barely take a person when full of fuel? I'm looking at a Mooney M20k, with extended fuel tanks, that with full fuel it is just 170lb under MTOW.

How does it only have roughly 850lbs of useful load?

The Internet seems to think M20Ks have something like 1100lbs of useful load; I can understand losing some useful load to the extended tanks themselved, as well as air conditioning, deicing, or something like that, but 250lbs? What's been installed in that thing?

 

[Ed Haywood]

Interesting thread considering we just passed the 20th anniversary of the plane crash that killed Aaliyah and 8 others. Pilot was a real piece of work.

Investigation determined that when the aircraft (CESSNA 402) attempted to depart, it was over its maximum takeoff weight by 700 pounds (320 kg) and had one more passenger than it was certified to carry. An informational report issued by the National Transportation Safety Board (NTSB) stated, "The airplane was seen lifting off the runway, and then nose down, impacting in a marsh on the south side of the departure end of runway 27."It indicated that pilot Morales was not approved to fly the aircraft. Morales had falsely obtained his FAAlicense by showing logs of hundreds of flight hours he had never flown. He may also have falsified the number of hours he had flown to get the job with his employer, Blackhawk International Airways. Additionally, Morales' toxicology report revealed traces of cocaine and alcohol in his system. The NTSB reported that the maximum allowed gross weight of the aircraft was "substantially exceeded" and that the center of gravity was positioned beyond its rear limit.

All true, but there was also some of that "we are too important to be delayed" factor at work. The pilot apparently argued with the passengers that the aircraft was too full for safe flight, but gave in under pressure.

 

[FlyingTiger]

Yea, it's hard to believe people would be arguing to take off in an unsafe condition but apparently that's what happened. Ultimately it was up to the pilot to make the proper decision and unfortunately based on his track record wasn't the type to do it. They should have just made the 300lb bodyguard stay behind, might have been ok.

 

[oskrypuch]

....
Maybe if this airplane is weighed the "useful" load with fuel tanks goes from 170lb to 270lb... at least that makes room for one adult with luggage and some extra margin.

If could, but more commonly, a reweigh of an aircraft will result in it losing useful load.

* Orest

 

[Racerx]

'Go places' planes like the Mooney, Bonanza, etc., should be able to safely cover 500-600 nm in one leg, with the airplane's seats and interior volume reasonably occupied. Piper really did at least do this part correctly, most PA-28 will carry at least 800 lbs and the Six / Lance / Aztec all do really well with useful loads. Bonanza are pretty but they're realistically a 2-3 person plane if you're actually using it to go places

Curiously you left out Saratoga. Perhaps because the useful is down right putrid compared to its older siblings. Talk about the younger generation getting fat!

 

[Tantalum]

Curiously you left out Saratoga. Perhaps because the useful is down right putrid compared to its older siblings. Talk about the younger generation getting fat!

haha! That was no accident on my part!

 

[Bell206]

but more commonly, a reweigh of an aircraft will result in it losing useful load.

Just for context, short of any non-strip repaints or extensive interior upgrades it's been my experience to gain useful load/reduce empty weight in both airplanes and rotorcraft after an actual weight/balance. Most of the error causes I've seen are improper rounding of numbers and math errors in previous EWB calculations especially if dealing with negative datum numbers.. Regardless, yes a reweigh can go the other way but I've found it not as common.

 

[Racerx]

haha! That was no accident on my part!

I figured as much. The Malibu is about as useful.

 

[Snowmass]

The gross weight number is an arbitrary choice from an engineering standpoint. What is safe depends greatly on what performance is needed to take off, climb and to clear terrain. Under gross could be dangerous and over gross quite safe. As to structure wing stress is limited by wing lift not weight. Landing gear stress could be greater landing or taking off on a rough grass strip at gross than a smooth landing or takeoff on pavement over gross. However, keeping weight within the CG range is very important for control. Weight too far back is especially dangerous as it affects recovery from a stall or spin. Too far forward may prevent landing flare or, in an extreme case, not even being able to raise the nose to takeoff.

 

[pmanton]

Years back I bought a PA-22. I was amazed at how light it was and how much useful load it had. I loaded it up with camping gear, gas and wife, and off we went to Arlington, WA for the big EAA West coast fly-in. It flew like a pig and guzzled gas.
When we got home I weighed it. The logs had it 200# light.

 

[Tantalum]

I was amazed at how light it was and how much useful load it had

Seems common with older planes, especially Piper. There are some PA-28 series off shoots that have tremendous usefuls (I think the Dakota is one of them? Handily beating out a 182). I had 6 adults and full tanks in the Aztec and did the WB several times.. every way I sliced it we had about 150 lbs left to spare.. unbelievable

We also comfortably got 4 people in there plus camping gear for Death Valley this past spring.. we were about 250 pounds under on this trip.. those coolers and bins are full

 

[Albany Tom]

Dakota is a great plane. I kinda like all of the PA-28's. But the 150's, while they have good payload, watch that climb rate on high DA. My experience is the 70's book performance values are more than a little optimistic.

 

[exncsurfer]

I guess I'm lucky, I could pilot OP's full fuel example plane with my flight bag and clothes on and still have 20 lbs. to spare for 'stuff'.

Or, not so lucky, if I get challenged to a sumo wrestling match.

 

[steingar]

..and your tanks are probably not unreasonably huge. Most PA-28 also have around 900 or so useful, at least.. with 50 gallon tanks topped off you can still get 3-4 people in there, depending and with 50 gallons fly a solid 4 hrs.. pretty much at the limit of the amount of time most want to sit in a small GA, esp as passenger

The OP is talking about a plane that, with full tanks, basically makes it a one (skinny) person plane. What's the point of tanks that huge? With the M20K miserly fuel burn are you every really going to need more than 50-60 gallons anyway? For 75% of your trips.

I agree that HUGE tanks just seems like an extra headache in most situations.

My plane holds the same as my old Pa-28, probably holds the same as every airplane on this board except those with tip tanks. 50 gallons or thereabouts. In my Cherokee that would give me just as much time aloft as in the Mooney, probably just a bit more. But in the Cherokee I'd go about 2/3 as far, again, maybe less. I would love more gas, if I ever get the cash I'll increase my aircraft's fuel capacity. The point of big tanks is flexibility. The fastest aircraft is the one that makes fewer fuel stops. That's why you see tip tanks on so many aircraft.

 

[Tantalum]

The fastest aircraft is the one that makes fewer fuel stops

Fair point

 

[Salty]

Fair point

It is, but not a particularly compelling one. I'd rather take an hour break refueling and taking a break in the middle of the trip and arriving at the same time, rather than spending the entire time sitting in the plane.

 

[oskrypuch]

Seems common with older planes, especially Piper. There are some PA-28 series off shoots that have tremendous usefuls (I think the Dakota is one of them? Handily beating out a 182). I had 6 adults and full tanks in the Aztec and did the WB several times.. every way I sliced it we had about 150 lbs left to spare.. unbelievable

We also comfortably got 4 people in there plus camping gear for Death Valley this past spring.. we were about 250 pounds under on this trip.. those coolers and bins are full

View attachment 99686

Yes, nominally 1200lbs useful load in a four-seater Dakota (PA28-236), and 900nm range to vapors, I quite enjoy that flexibility in mine.

The older variants of the Dakota (Pathfinder/Charger), the PA28-235, some were as much as 1350lbs useful, but they are a bit slower and a lower service ceiling.

* Orest

 

[RussR]

What totally doesn't make sense is having an airplane that with full flow it can take only 170lb extra. Again, there is no room even for the pilot. And totally agree, 9hs on a mooney or any GA aircraft is madness.

Well, there are a lot of sub-170 pound people out there. Some are pilots. I'm not one of them, but wish I was (okay, at 6'2", being sub-170, maybe not a great look...)

9 hours might be extreme in a GA airplane, but people do it. More likely, though, is how about a 4-hour flight to somewhere with no fuel (or really expensive fuel)? That gives you enough to fly there and back without refueling, and is a totally reasonable trip in GA.

I completely agree. And the argument that "just don't fill it to the top" is a fatuous one.. who actually has a totalizer / fuel gauges they trust that much and has the ability to off load fuel easily..?? anyone? Let's say you flew alone with full tanks, you only did an hour and you filled it because gas was cheap at the podunk place you went for lunch. Oh surprise, the next weekend you decide to take an impromptu trip and need to take your wife, son, dog, and bags for a weekend to someplace 300 miles away.. good luck offloading 40+ gallons and doing it safely/accurately and threading that line between between overweight and having enough gas

When I started flying bigger/faster airplanes than the typical rental fleet, I quickly came to realize that the "fill it up (or to the "tabs") after the flight" idea is no longer workable, and is no longer really "normal" procedure.

For example, one airplane I fly is a PA-46. It has 120 gallon tanks, enough to almost go 1000 nm (without reserve). Fuel full makes it really a two-person airplane if they're typically-sized adult men. So yes, if I fill it up at the end of each flight, yes absolutely if the next flight is with 4 adults I'm screwed. So what's the solution? Easy - don't fill it up. In fact, I don't fuel it AT ALL after a flight. It usually sits there with an hour or two of fuel in it. Then when my next flight comes, I put in the fuel I need for that flight. (Incidentally, the PA-46 has the best system of fuel tank "tabs" I've seen. It has indications for 25, 30, 40, and 50 gallons per side.)

I also fly a Cessna 421. Full fuel is about 253 gallons. That's 1500 pounds of gas! So, same story - I don't fuel it after flight because I don't know how many people I'm taking next or where I'm going. And even if I can fit everybody with full fuel, that's not necessarily wise in a twin. If I can safely carry 500 pounds less fuel, then that's 500 pounds of improvement in single-engine performance. Pretty significant.

Yes, fuel planning gets more complicated the further you move up. Of course it does. Just like weather planning or runway length planning or anything else.

 

[genna]

^^ this!

I'm well under 170lb. Also, consider when many of these planes were designed. We were a lot shorter and lighter.

 

[FastEddieB]

When I started flying bigger/faster airplanes than the typical rental fleet, I quickly came to realize that the "fill it up (or to the "tabs") after the flight" idea is no longer workable, and is no longer really "normal" procedure.

That works equally well on smaller/slower planes.

The "cheat sheet" on my Sky Arrow with just 17.8 gals of useable fuel has me generally aiming for a half tank or less after a flight:

With a half tank I'm good to go with a passenger up to 230 lbs with no baggage and can fly for just under 2 hours to empty, enough for a short local flight. Like you, I generally just add the fuel I need for any given flight just before the flight.

 

[Tantalum]

Incidentally, the PA-46 has the best system of fuel tank "tabs" I've seen. It has indications for 25, 30, 40, and 50 gallons per side

this is great, I really wish more planes had something like that, it would take the guesswork out. The Duchess has 30/40 marks on there, the Aztec I fly doesn't have any!

 

[Stewartb]

With the addition of an important part and a few hundred dollars for paperwork my gross in my 180 went from 2800# to 3190#. Similarly a Supercub can go from 1750# to 2000#. Airplanes without the paper can easily and safely fly at those weights.

 

[David Megginson]

With the addition of an important part and a few hundred dollars for paperwork my gross in my 180 went from 2800# to 3190#. Similarly a Supercub can go from 1750# to 2000#. Airplanes without the paper can easily and safely fly at those weights.

When I got the paper-only STC to take my 1979 Piper PA-28-161 from 2,335 lb to 2,440 lb (like the later -161s), it required me to use a later set of performance tables as well (and to keep them in the plane). The STC itself removes an excuse for the insurance company to push back if I bend a wing some day with the plane fully loaded.

 

[Rockymountain]

How useful is a plane that can fly 10 straight hours and not have an occupant need a bathroom break?

Travel John, chemical absorbing packs. Problem solved. And if you are traveling over hostile weather, hostile terrain, or just want to skip a customs stop on the way somewhere, that range is great utility.

 

[Checkout_my_Six]

I flew….over weight today. I need to lose a few pounds.