Said one who never engineered, built and certified airliners.

BTW, Mitsubishi spent 7 years in flight test and could never get their jetliner out of flight test. They closed that door about 2 years ago.

Except for the 737 (old cert design), all Boeing's today have auto stab cutout for runaways. There are no memory items. Use the checklist and do it right the first time. For those of us who flew DC9s, MD80s, 727, 737 we always had training every sim session. I once had a sim partner start slapping the 747-400 guarded cutouts for a stab EICAS message. He said, thats what he thought he should do because he has done it before on the MD-11.posting.php?mode=quote&f=49&p=3189318#

Boeing Airspeed Unreliable procedures are there to buy you about 10 minutes. To safe the airplane under all weights, models (think 777-200 thru 300ER or 747-200 thru -8F), CG and altitudes. They couldn't possibly have you memorize all those number thus one set of numbers.

Once you get into the QRH, you then you find your flight conditions and trim pitch and power that value. Believe me, engineering simulations had major panels shred with varying changes in pitch and power from book. Fly these numbers, immediate action and QRH values.

Lastly, these procedures were developed by CAST (look it up) and used as a templet by all OEMs. Airlines can develop their own but own this liability.

1. FPA derives its data from ADC, and can be corrupt. 2. Too much thrust can shred panels and parts. Too little thrust can lead to stall. You add what is required and called for by procedure. Nothing more, nothing less.

I disagree that the AIRSPEED UNRELIABLE builds time, it builds complications.

You're cruising at FL350 at M0.8 just like Air France 447 and you get the same situation. Immediate action is to set 4deg and 75% N1. If it takes 10 or so minutes before you get to the specific parameters (not unreasonable for the avg unsuspecting crew to get to the QRH, read the first 6 steps, go to the Performance section, find the correct table, and find the correct values), they will have lost 40 or more knots of airspeed. Now they set the pitch and power required to HOLD 290/M0.78 and have to wait until the aircraft is in trim and stable to see which indicators show 290/M0.78....in practice, do you think most crews wait long enough? It may take 10+ minutes to gain 30 or more knots at FL350 with 90%N1 set, it takes almost a minute to gain 10kts at max power.

Any correct indicators will show much slower than 290/M0.78 when the crew thinks they're stable. And, they'll choose the one that's closest to 290/M0.78 to be the "correct" indicator because that's what they think the QRH says to do. It actually doesn't, it says can a reliable indication be determined, but it also leads them to believe that any indications within 30kts of the desired value may be correct. If I make more than one (or all) indications invalid like AF 447, and I make an incorrect indicator the closest to 290/M0.78, it's well above 50% of the crews that choose that one to be correct.

Had I had them fly 2 deg and 90% N1 if at cruise, no matter what weight or FL, they would have been much better off.

In reality, it's much safer to just think they're all bad and fly pitch/power until you know one is valid. Had AF447 done that, either when they left the wx, or descended to lower air, they would have gotten their indications back. But the industry position is that pilots are no longer capable to do such things as setting pitch/power based on phase of flight vs flaps up/down, so they say fly 4 deg / 75%N1 if the flaps are up, no matter if you are at 1,000' and 230 kts or FL400 and M.81, then take the 10 minutes to go through a QRH.

I’m in total agreeance with your opinion.

I actually ran this procedure during a 737-800W sim fidelity / evaluation session the other day. Max alt FL402. Climbed to FL400 and set 4’/75%. Left it there for as long as I could, given time constraints (approx 8 mins). Speed settled slightly below min drag speed and started a slow descent. The sim evaluation was part of extended envelope certification for this device , the amount of data provided for upset and stall characteristics is impressive. We tested for a clean, an ice loaded airframe, with and without anti ice and weight/MAC/environmental conditions, EFS function, STS operation, buffet, stick shake then post stall as well as with wing drop . It was a comprehensive program involving several sessions ,it was the first one of these programs I’ve been involved in. Boeing don’t make this stuff up, I follow their data including what’s contained in a NNC.

Setting 4’ is a simple process of “putting the wheels on the horizon” on the PFD. I also conduct post maintenance functional check flights, including manual reversions but can also include virtually any system that requires a flight test for evaluation or acceptance. Once again there is a procedure and a strict flight regime to follow with comprehensive data. I follow the procedure. I understand why and what we are trying to achieve …but I follow the procedure , it’s there for a good reason and I’m saving making up my own procedures for when the situation is outside the scope of any NNC. I understand some NNC procedures may not be perfect for every situation, but they have been risk assessed and if followed will provide the desired outcome.

By the way, the reason I ran out of time in the sim was for the same reason. We had a procedure and sequence to follow. So we did exactly that. I only had about 8 minutes left to run the 4/75 scenario prior to handing it back to the sim techs .

I’ve seen enough people think they know better only to eventually discover they don’t.


This extract below discusses human factors for a functional check crew member. I personally consider such qualities essential in any line captain and reinforce such behaviours during training.

1. FPA derives its data from ADC, and can be corrupt. 2. Too much thrust can shred panels and parts. Too little thrust can lead to stall. You add what is required and called for by procedure. Nothing more, nothing less.

I don't teach people to make up their own procedure, I teach the potential downfalls of the procedure. Most line crews have no idea, once they transition from the 4deg/75% to the charted values, what 4deg/75% did to their airspeed, so they think they're starting from where they were, not where they are.

The 767 Left & Center HYD SYS PRESSURE checklist says all autopilots, including the Right Autopilot, are inop; the right autopilot is not inop, it's just that the right autopilot can't trim. If you configure and trim, the Right A/P works fine. Most crews don't know that. Why doesn't the QRH say that? Is it because they think pilots can't accomplish that task or handle that systems knowledge?

The Right HYD SYS PRESSURE QRH says autobrakes aren't working, but not that the entire normal brake system is inop and you're on the alternate system. Does it matter? I'm sure there's a scenario where that'd be good to know.

The PACK OFF checklist says continue normal operations if it's just a single pack that's inop. The MEL says the aircraft must aircraft must remain at or below FL350. Why doesn't the QRH? What if you lose a pack and are at FL390 to get over weather or are over water and need FL390 or above for fuel not knowing that one pack may not maintain cabin altitude, you'd have no idea about the FL350 limit from the QRH alone.

It's not just a Boeing thing, it's just that they are on the same track as the rest of the industry. It used to be that people said Airbus designed aiplanes to be flown by third-world countries. Now that's everyone. Systems knowledge is not seen as the necessity it once was, we have computers, automation, and NNC's. And it's not even like it's available and just not mandated, it's almost as if it's purposefully withheld. Try finding detailed information on VNAV as a line crewmember!!

The lack of systems knowledge is noticeable if you look for it. I've seen crews try to validate IAS by looking at TAS (hint, TAS is based on IAS) or winds (hint, winds is based on IAS). I've also seen crews switch both sides to a single ADC, then later try to use the fact that both sides are saying the same thing as validation of what they are showing.

It's evident when you hear some people say that you MUST always resort to and follow the QRH (vs be a pilot). What if you roll from Flaps 15 to 20 and feel a signifcant roll develop before the Flap Disagree or Asymmetry indication displays or if it doesn't display yet, can you immediately roll them back to 15 and do a Flaps 15 landing? Some actually say no. So, if it's impending Asymmetry, you need to allow the asymmetry to lock out the flaps and now land with that permanent roll tendency? Same with even trying the right autopilot with the L&C HYD PRESS failure. The QRH says it's INOP, so you can't touch it.

It's also evident in the mishap reports. It's funny that so many people are so quick to say that the 737-MAX mishaps wouldn't have happened if they were western crews, when it was fully trained and qualified western crews that couldn't handle an UNRELIABLE AIRSPEED (Air France 447) and inadvertent go-around activation (Atlas mishap).

I've only had an 800NG at Max Alt once. Won't do THAT again - it does not like it. A bit too close to coffin corner for my liking.

2000' above OPT in the B767 and B777 never seemed to be an issue.

I don't teach people to make up their own procedure, I teach the potential downfalls of the procedure. Most line crews have no idea, once they transition from the 4deg/75% to the charted values, what 4deg/75% did to their airspeed, so they think they're starting from where they were, not where they are.

The 767 Left & Center HYD SYS PRESSURE checklist says all autopilots, including the Right Autopilot, are inop; the right autopilot is not inop, it's just that the right autopilot can't trim. If you configure and trim, the Right A/P works fine. Most crews don't know that. Why doesn't the QRH say that? Is it because they think pilots can't accomplish that task or handle that systems knowledge?

The Right HYD SYS PRESSURE QRH says autobrakes aren't working, but not that the entire normal brake system is inop and you're on the alternate system. Does it matter? I'm sure there's a scenario where that'd be good to know.

The PACK OFF checklist says continue normal operations if it's just a single pack that's inop. The MEL says the aircraft must aircraft must remain at or below FL350. Why doesn't the QRH? What if you lose a pack and are at FL390 to get over weather or are over water and need FL390 or above for fuel not knowing that one pack may not maintain cabin altitude, you'd have no idea about the FL350 limit from the QRH alone.

It's not just a Boeing thing, it's just that they are on the same track as the rest of the industry. It used to be that people said Airbus designed aiplanes to be flown by third-world countries. Now that's everyone. Systems knowledge is not seen as the necessity it once was, we have computers, automation, and NNC's. And it's not even like it's available and just not mandated, it's almost as if it's purposefully withheld. Try finding detailed information on VNAV as a line crewmember!!

The lack of systems knowledge is noticeable if you look for it. I've seen crews try to validate IAS by looking at TAS (hint, TAS is based on IAS) or winds (hint, winds is based on IAS). I've also seen crews switch both sides to a single ADC, then later try to use the fact that both sides are saying the same thing as validation of what they are showing.

It's evident when you hear some people say that you MUST always resort to and follow the QRH (vs be a pilot). What if you roll from Flaps 15 to 20 and feel a signifcant roll develop before the Flap Disagree or Asymmetry indication displays or if it doesn't display yet, can you immediately roll them back to 15 and do a Flaps 15 landing? Some actually say no. So, if it's impending Asymmetry, you need to allow the asymmetry to lock out the flaps and now land with that permanent roll tendency? Same with even trying the right autopilot with the L&C HYD PRESS failure. The QRH says it's INOP, so you can't touch it.

It's also evident in the mishap reports. It's funny that so many people are so quick to say that the 737-MAX mishaps wouldn't have happened if they were western crews, when it was fully trained and qualified western crews that couldn't handle an UNRELIABLE AIRSPEED (Air France 447) and inadvertent go-around activation (Atlas mishap).

The MEL says must remain at or below FL350 for all operations, not “must not dispatch above” or remain at or below for certain ops. That means you can’t climb above 350 at all.

The QRH says continue normal operation for all operations. That means you can fly at FL410 regardless of the situation. The only caveat is to break out the CO2 monitor if doing Dry Ice Supplemental. There is no requirement to consult the MEL in flight.

If there’s a reason to not fly 1 pack above FL350, it should be in both. If it’s a what-if, then it should be a “not dispatch above” in the MEL and let the crew decide, but have the fuel, etc for 350 and below.

Your response does not explain why the difference between the two. And neither do my documents, which was my previous point. If I lose the pack a minute before takeoff, there's a limit, a minute after takeoff and there's none. There's obviously a reason for the difference, but pilots can't find the answers even if we tried. That's the Airbus philosophy coming out.

It's always been this way. In the MD-80, we were limited to FL250 w one-pack DDG inop. So the later models 737NG were way better.

The FAA says we need to account for a pack failure even if we have one deferred. You also need to account for the other airplane services to like smoke detectors, anti-ice systems while maintaining cabin pressure.

Lastly, when I flew flight test on the 777-300ER, with all packs off at FL430, we would only see a cabin climb rate of about 600 FPM. This was on a tight, new aircraft. It's never as bad as some people seem to think if we lose all packs.

The CRJ MEL for max altitude with one pack inop was different from the AFM/QRH limitation (the MEL had a lower altitude), for what it's worth. There was a different set of numbers for the different versions of the airplane. They're all sort of a jumble in my memory but I do remember the dispatch limitations vs "it just broke" were not the same.

Just to clarify the original point, I was only using this as several examples where we aren’t given enough info anymore, such as needed to determine why not “must not dispatch above”, which is what I’ve seen before, vs “must remain below”? To the point I originally brought it up, it’s the demotion of the pilot in the big scheme of things, where we used to have the info and flexibility to make these decisions. Scanning the entire MEL, the “must not dispatch XXX” are largely gone. If I defer a pack, I need to declare an emergency to go above FL350, if it fails right after t/o I don’t.

Some of these things I understand. We used to be able to pull/reset c/b’s. But, as these systems become more inter-related, resetting c/b’s for one system may affect many. Airbus’ approach for the A300/310 was to provide a list of c/b’s that can be reset for various malfunctions without consulting Mx. Boeing has no equivalent, not even for something as simple as the ACARS printer.

Sometimes they do give the info. An inoperable fuel pump requires minimum fuel levels, but the MEL makes it clear the reason is to ensure the intakes of the operable pumps remain covered.

A lot of these MEL/QRH differences usually only come up in the “would you declare an emergency?” discussion. Dispatched with one pack and have to go above FL350? No choice, you must use your Capt emergency discretion if there’s no other option than climb. Or, you lose anti-skid in flight, declare or not? On the no side, people note that you can dispatch without it, so why declare? On the yes side, there are a lot of Mx procedures (pulling c/b’s, etc) that aren’t accomplished for the QRH, so you don’t know what the impact may be.

A lot of malfunctions are only in the MEL, most notably failures of the buttons/switches on the MCP panel, display failures, etc. Most line pilots haven’t thought about workarounds for these things (such as the ability to switch the EICAS display from side to side with a center display failure) and the MEL is the only place to find them.

All of the above is why I fall back on my Airbus training to fly the Boeing. We used to say in the Airbus “Phase Ones, time permitting ECAM, time permitting QRH”. For the Boeing, if you want to have the most info available (for whatever that’s worth), it’s “QRC/QRH, time permitting MEL (for reference only), time permitting aircraft systems manual”.

So, my question is when we have these discussions, why not a note in the QRH that says descent below FL350 may be required if XXX, YYY malfunctions occur when operating on one pack? It’s obviously a factor, so a quick note would better prepare a crew to be looking for other associated abnormals.

It has nothing to do with the pack malfunction itself, just the lack of info with obvious contradictions.