A few days ago, I flew out of Norfolk, Virginia on a relatively new jet - an Embraer 170.
About 10 minutes into the flight, the alarmed pilot came onto the intercom - we didn’t have enough “wing power” to make it to Chicago. We turned around and made an emergency landing back in Norfolk.
After the initial “WTF” reaction, the whole thing smells of bullshit to me. Is there some legitimate problem that he could have meant to explain, and communicated poorly? Or do you think it was something more serious, but he didn’t want to alarm us on the plane?
“Wing power” there’s a bullshit phrase if ever I’ve heard one. Are you sure you didn’t mishear?
Reasons for turning back could be a security alert as mentioned in the above post.
Quick anecdote: I recently read about a Captain who returned to land after one of the hostees told him to “turn around”. She actually meant for him to physically turn around and look at the cockpit door, it was unlocked. A lesson in (un)clear communication.
Or it could be that they didn’t have enough fuel. The weather at the destination dictates the amount of fuel that you need to plan to have when you reach that destination. A change in forecast may mean that you no longer have the required legal fuel for the trip, e.g. the weather at L.A. has deteriorated to the point where you must arrive with enough fuel to get to an alternate destination in case a landing is not possible at L.A…
Or it could be a mechanical problem. Most systems have backups but it is not uncommon for an aircraft to be departing with an unserviceabilty and a further unserviceabilty on a similar system may mean the aircraft can no longer legally continue with the flight.
The wings on a passenger jet have various powered systems, from motors to raise and lower flaps to the “di-icing boots” or various other ice prevention and removal system. Many of these require power. So, yes, there could have been an interruption in power to one or more of these systems.
If, for example, the power to the anti-ice systems failed and there were ice-promoting conditions aloft (not too uncommon this time of year) then continued flight would have been extremely unwise and turning around is a good option.
I do agree that the term “wing power” is a bit vague… but a long, involved, and highly technical explanation probably would not have benefitted anyone, and really you want the pilot focused on flying the airplane, not explaining what’s wrong with it in great detail to a bunch of laymen.
I was on a flight to MPLS yesterday. We sat on the runway for about 20 minute while they did “last minute calculations”. Later the pilot came on the intercom and said “Well folks, it’s a good thing we double-checked the math because we’re too heavy for this runway. We’re gonna go ahead and taxi to a longer one.”
I don’t know what they do about passengers, unless they assign an arbitrary pounds-per-head or kilos-per-head value, but the luggage is weighed and the fuel has a known weight per gallon. (In fact, fuel is measured on planes by weight, not volume.)
I thought I remembered that some planes have deflection sensors in the landing gear, so that if the plane is sitting still, you can measure the deflection from a calibrated tare and estimate the change in weight and the change in center of gravity (with three measurements). So the plane parks, the pilot hits “tare”, and then the pilot or the fuel sensors automagically subtract of any fuel already in the tanks. Then passengers, bags, cargo, and fuel are all brought on. Not sure if that’s in all planes, military cargo planes, or what. I’ve been in about six cockpits, half civilian / half military, and can’t remember which one was which.
What I should really do is ask my uncle, whose job is to balance the load on Virgin Air’s flights leaving from Orlando. He needs to optimize the plane’s payload to get as much paying cargo onboard as possible (“We’re showing 100 empty seats, so go ahead and ship the bronze statue on this one”) while keeping the cargo’s CG as close to the center of lift as possible and optimizing the plane’s cost efficiency.
I think I remember seeing this too, but on B-52s on ‘the apron’. A buddy of mine is [sub]still[/sub] a B-52 Radar/Nav, and I he brought me out to take a look one day during an exercise (which was kind of cool to see a BUFF loaded for nuclear war!). I vaguely remember seeing weight/pressure indicators on the “truck stems” of the landing gear. But I didn’t ask about those, so now, naturally, I’m kicking myself in the ass.
[hijack] I’ve heard that it’s this very profitable freight shipping that is driving the “two checked bags per passenger” rule. Seems they’re trying to squeeze every last dollar out of profit at the customer’s expense. [/hijack]
Hrm, I guess I shouldn’t say “hijack” in a thread about airlines. :rolleyes:
My understanding (no cite, of course) is that it’s not just a matter of knowing how much the plane weighs. It’s a matter of knowing what the acceptable takeoff weight and and required runway length are for that airport on that day. This can vary with elevation, barometric pressure, wind speed and direction, and temperature, as they all affect the amount of lift at a given ground speed.
Some very new commercial airliners (like the Boeing 777) can sense their own weight and CG. Older airplanes require planning: as mentioned, passengers are assigned a weight and baggage is weighed. Fuel onboard is measured in pounds, and the Basic Operating Weight (BOW) of the aircraft is known. Add them all up and you have your current ramp weight.
Sometimes we operate very close to the limits. There are airplane limits and runway limits: airplane limits are structural limits on the airframe, and runway limits vary with the runway. For example, we can take off at max gross weight on runway 18L at DFW: 13,000 feet of runway at an elevation of about 600 feet means we have all the runway we need.
But when you look at shorter runways at high altitudes, your allowed weight decreases due to performance issues. We cannot take off from Orange County, CA at max gross weight: the runway is just too short.
As to the OP:
I have no way of knowing what happened to your airplane, but I’ve never used or heard the term “wing power”. Sounds like the pilot was grasping for something to say and came up with whatever came to mind.
As to the speculation on anti-ice power: the EMB-170 uses bleed air for wing anti-ice, as almost all jets do. The wing design is very efficient, and boots would disrupt things too much. Anti-ice boots are used on turboprops a lot, but almost never on jets.
FYI, “bleed air” is air taken from the engine (“bled” off), usually near the high-stage compressor (before combustion). This air is extremely hot and is ported to the engines, wings, tail, etc for heating during icing conditions. It’s also used for pressurization, but it’s cooled before it enters the cabin.
Thank you, pilot141 for clearing up the waters I might have inadvertantly muddied.
(Gosh, it really shows which end of aviation I work with, doesn’t it?)
Anyhow - another example of why I think airline pilots should either keep it short, sweet, and to the point or just not say anything. Of course, if they didn’t come up with interesting things like “loss of wing power” we might not get as many aviation threads on the SDMB, which might be a loss for some of us.
I’d guess you are right. But that pilot should probably have considered that while a phrase like “loss of wing power” might possibly reassure some folks, anyone with any knowledge of aviation who hears it is likely to be saying “What in the heck is this lunatic talking about?” It’s not in fact a reassuring explanation.