I'm trying to imagine how de-icing could possibly affect the plane's electrical system and the only thing I can come up with is that glycol somehow got inside the engine cowling and came in contact with an engine-driven generator. This wouldn't be human error. More likely it would result from a cowling access panel not being secure.

I guess another possibility is that glycol came into contact with the electrical busses, located in the Electrical compartment. On the 757/767, there's a access door for this compartment located on the forward bottom of the fuselage. Seems hard for glycol to get in there, but who knows?

But that's all wild conjecture and I've never heard of anything like this happening. It's also possible that the plane had electrical problems completely unrelated to the de-icing and it was just coincidence. I'd love to hear the definitive finding on this.

I have been on several flights in the past where the pilot mentioned the APU was not working, but we would be able to fly in spite of that. I remember you saying previously ITT that was not a problem. However, doesn't the APU provide power in case of total engine failure (I know a rare thing)? Do all planes have a RAM air turbine? Is this all playing the odds and that's why you can fly with a non-functioning APU?

We're required to have two sources of electrical power at all times while in flight. Those two sources are normally engine-driven generators. The APU provides a backup so that, for example, if one engine-driven generator is deferred (i.e. currently not working and slated for later repair/replacement) we can still make the flight by simply running the APU for the entire flight.

Most of the time, we shut down the APU after starting one engine and we taxi out using just the one engine. Fuel savings is big these days and the APU will use about 400 lbs/hr iirc (that's about a gallon a minute). We hold off on starting the other engine for the same reason and, when we do start the 2nd engine, we use bleed air from the first engine, instead of the APU, to spin the starter.

With two engines running, each engine provides electrical power to a separate electrical bus. When only one engine is running, its generator automatically picks up the load and provides power to both buses. So even if the APU is running, it doesn't share the load. It's simply there as a backup if the single remaining engine-driven generator fails. In that case, the APU generator automatically picks up the load of the both buses (i.e. it can power everything).

This discussion is for twin engine planes. On planes with more engines (e.g. MD-11, B-747, Airbus 340), there is even more redundancy in electrical supply.

Every Part 121 plane (airliner) has some additional form of backup for electrical power. The minimum requirement is that the ship's battery can provide at least 30 minutes of power for essential items (i.e. the Captain's avionics and communications).

The CRJ has an ADG (Air Driven Generator), which automatically deploys from the right front of the plane if all electrical power is lost. It has a small prop which turns in the slipstream to power a small generator capable of powering essential items.

CRJ Air Driven Generator



The 757 has a Ram Air Turbine (RAT) which deploys automatically if both engines fail. It's purpose, however, it to power the center hydraulic system so that the flight controls still work. For many 757s, the only electrical backup is the battery (i.e. the 30 minutes mentioned above).

On some 757s and 767s (including all of the ERs), there is an HDG (Hydraulically Driven Generator). If all electrical power is lost, the center hydraulic pump turns a small electrical generator to power essential items. This is necessary for international operations, obviously, because the 30 minute backup provided by the battery might not be enough to get on the ground.

Since you have flown both the MD80/88 and the B757/767, which one has the better ability for short field landings and take offs assuming everything is the same, i.e. weight, fuel, etc... I have read other forums and get different answers. I thought the original intent of the DC-9 was for these very things, by putting the engines in the back?

The DC-9 was able to get into smaller fields because it was a smaller, lighter, airplane. It only carries about a hundred passengers vs. the 757 which carries about twice that many (our 757-300 model carries 224 pax).

The later variations on the DC-9 design, such as the MD-88, are stretch versions of that plane and can carry about 50% more passengers. When I flew the MD-88, it was configured for 142 passengers for mainline operation and 134 passengers for the shuttle operation.

But if I go with your premise, i.e. assuming the same weight, then the 757 should do better because it has bigger brakes which will be more effective in dissipating that kinetic energy. Brakes are the most effective thing in bringing a plane to a stop. Reverse thrust from the engines is a much smaller factor in stopping distance.

Any thoughts on this event?

http://boardingarea.com/blogs/onemil...medium=twitter


I enjoy reading his blog. I think he is overly critical on the pilots making an announcement during the event (like you said they are more than likely too busy keeping the place in the air) but it seems outrageous for them to not make any sort of announcement once on the ground.

On a recent flight with WiFi and with the help of planefinder.net, I was able to track my flight along with several others along the same flight path, going to the same destination. I was curious to see 3 flights all with different altitudes and speeds going to the same place separated by a hundred miles or so. Why different altitudes and speeds along the same flight path and destination?

Also, do you like the iPad in the cockpit? Do they disable all the "fun" features?

It seems horrible that they allowed themselves to be held in a thunderstorm, but of course we don't know the whole story.

W0X0F, one of the commenters on that article said that Royal Jordinian airlines has a corporate policy that prevents pilots from questioning ATC and requesting alternate routes around storms among other things. That seems absolutely nuts to me. Have you heard anything like that?

I really like Ben's blog too. I believe him that it was pretty bad given that he spends a TON of time in planes.

If you've read this thread, you know that I'm a big proponent of announcements from the cockpit. I travel in back a lot, commuting to work, and I know how annoying it can be to hear nothing from the front office during delays or abnormal situations. Sure, there are times when things are too busy up front (as in my recent medical divert, discussed recently itt; we asked the flight attendant to make the PA), but it sounds like this was a prolonged event and they could have certainly found the time to make a reassuring PA.

I may have to bookmark this guy's blog. I enjoyed reading it.

I've never heard this and I'd be surprised if it was true. But who knows with foreign carriers (especially those of a monarchy)?

Each company's dispatcher will decide on what altitude and speed to fly and that could depend on their assessment of winds aloft and desired fuel efficiency. The best speed will vary from one type of aircraft to another (e.g. the 757 will usually be filed for a range of .78 to .80 Mach; a 747 will be filed for a faster speed, maybe even up to .84M). If the winds aloft are extremely favorable, the dispatcher may file for a slower speed to save some fuel; if the flight has a big delay, they may decide to spend the money and burn a lot more fuel to fly faster and make up some time.

We don't have that...yet. I've only seen it as standard equipment on USAirways flights, where it's actually mounted on a holder for each pilot. AFAIK, it has only flight related functions, e.g. approach and taxi charts.

Sorry if this has been asked before, but hypothetically let's say a terrorist becomes an ATC. Would he alone have any chance of successfully getting a plane to crash? What if two ATC's working the same or neighboring airports colluded, would there be any chance they would succeed?

I assume there are too many warning systems and controls to prevent this.

I'm sure a controller could give a better answer, but I don't think a terrorist mole would have much luck getting a plane to crash, whether into the ground or with another plane.

There's really nothing a controller could do that would cause a pilot to fly his plane into the ground, so that leaves causing a mid-air collision. This might have had some chance of happening before the days of TCAS, but it would be unlikely now. Even in the pre-TCAS days (or with planes not equipped with TCAS), the "Big Sky" theory of aviation would make any mid-air unlikely even if the controller conspired to put them on a collision course.

Well thanks for ruining breaking bad for me.

I was more interested in your thoughts on his flight experience. Why would a plane keep on a holding pattern in such terrible conditions instead of diverting or changing altitudes? Would any sort of frightful experience like this ever make you want to quit flying?

It's hard to comment on that without knowing exactly what the situation was, but changing altitude was probably not an option. The holding patterns associated with arrivals have several airplanes in them, stacked up at different altitudes. As the bottom plane is cleared to the airport for the approach, the other planes are given a descent in the stack. Also, changing altitudes while in severe weather is only going to help if you can climb above the weather. What you describe sounds like a mature thunderstorm and it probably topped out above that plane's service ceiling (i.e. the plane couldn't have climbed out of it).

Diverting sounds like the only realistic option but, again, I don't know the details. Maybe it was a "perfect storm" of low fuel state, airspace constraints and widespread severe weather that left them with no option but to ride it out. I'm not trying to be an apologist for the pilots, but I really hate being a Monday-morning quarterback when I wasn't there.

If I was going to quit flying, I've had my share of experiences that would have led me to that decision. Instead, the bad experiences have just made me more careful in avoiding trouble.

Here is a link to this PDF, up to date as of yesterday April 1st:

PDF - 2p2 thread - 1433(!) pages

And as an added bonus, here is the equivalent PDF summary of the ongoing thread with W0X0F that's also underway on flyertalk.com:

PDF - FlyerTalk thread - 272 pages

Happy Spring!

On a flight yesterday in a MD-80. We were behind a 737 for takeoff and I had a window seat looking towards the runway as the 737 started its roll and rotation. The 737 had just lifted off the ground when we stared our roll on a 7761 ft. runway. My thought was this is really quick behind the departing 737 and I was thinking wake turbulence, but once we lifted off, we turned really quickly, so my question is how soon after the wheels leaving the runway can you start to bank? Also, since the runway was being used for both departures and arrivals, I also thought ATC might be trying to squeeze us in before the next arriving plane and since there wasn’t a Heavy in front of us, the wake turbulence might not matter. You have mentioned ITT that passengers don't like more than 5 degrees of bank. Is that a company/FAA regulation or strictly for comfort? As a passenger, would we know if there was more than 5 degrees of bank?

to add to what w0x0f has posted, i don't know where you're at but what you list sounds quite similar to the flightradar app i got last month - if you're in the states, is it not possible that you're just getting different levels of lag from the faa? they delay their information for about 5 minutes which i'd guess may vary, unlike in the rest of the world where said apps have greater coverage using ads-b data reception which is close to real time

Our guideline is 400' agl minimum. That's not an industry standard, but it's probably pretty typical. In some cases we might start that turn just a tad early, for example when departing to the north at DCA which requires that we turn left to follow the river. There's prohibited airspace just on the other side of the river (White House, Lincoln Memorial and Congress), so on a hot day with a heavy airplane we'll start that turn even if we haven't gotten to 400'.

You're right about the wake turbulence. There's no need to delay a takeoff behind a 737 and it's not unusual at some busy airports to get clearance to takeoff just as the preceding aircraft is lifting off.

Did I say that? If I did, I'm not sure what I was thinking. Almost any time we bank, we exceed 5° of bank. The only time I'd use such a small bank angle is if I'm changing my heading by 10° or less. When departing the airport, our bank angle will usually be somewhere between 20° and 30°. If the roll into the bank is done smoothly, a passenger might not even be aware of it and often wouldn't know how steep the angle is unless they're looking out the window.

Yeah...maybe I had the 5 degree of bank wrong.

sixfour...yes, I'm in the states and there is a 5-minute lag time...real annoying!

I was just reading Captain Sullenberger's wikipedia entry here. He seems incredibly well educated and had a background of flying fighter jets in the Navy. How does someone like this only end up flying an Airbus320 that far into their career? In asking that I mean no disrespect to you or other pilots it just seemed like he would be a captain on a 777 or something equivalent.

I'm Canadian so I could be very wrong but I've always been under the impression that US Airways wasn't a good airline to fly/top company and bottom company out of the big US airlines. Was it a better airline in the past and somewhere where pilots wished to work? I took a brief look at their fleet and it seems that they have less of the big jets which would make me think there is less room for progression (ie salary increases)?


Do you know anyone that works for an elite airline (Emirates, Cathay, Etihad, etc.)? No idea if these type of airlines pay more or are attractive to pilots but they are certainly a pleasure to fly with.


If I had a pilot friend what would be the chance they could get ever get me into a simulator with them? Is this frowned upon? Is there a jumpseat or extra seating for people to sit in on?


This thread is awesome. If you ever find your way to Toronto send me a PM and dinner is on me.

depends on whether a/c are IFR or VFR, a/c speed/performance, where each is going and specific airport(terminal) rules

IFR or VFR? Not sure how that would affect the need for wake turbulence avoidance, but ok. Also, I don't see how the destination airport could possibly figure into this decision.

Typically, it's "heavy" aircraft and 757s that require takeoff delays (usually two minutes) for wake turbulence avoidance. The 737 does not fall in this category and I can't remember the last time I heard the tower issue a delay in takeoff clearance for wake turbulence behind a departing 737.