Easyjet B737 pitch-down incident 12 January

[sjm]

Did a test flight after a 'D' check(i think) full flying surfaces removed and replaced, manual reversion part of the sign off.

Test schedule used was caa required schedule and in the briefing between myself and capt we discussed this very senario, and how to deal with it. Those in the know with experience of test flights seem to expect this possibility, and brief the following:

Allow the aircraft to pitch down/up and respond by counter acting the pitch, however the interesting part is you have to remove all control inputs and put the hydraulics back on without trying to control the aircraft before thier back on otherwise the hydraulics kick in with max pressure and opposite control forces to the pitch.

not good

[Rainboe]

After 10 years flying the 737, I have expressed the opinion here before that it is an emergency 'keep you in the air procedure' only. It can be flown in manual reversion with not a lot of control. Control forces are very high requiring both pilot inputs. Control is bizarre, it is impossible to fly with any degree of accuracy or logical control. I have only tried it in the simulator and have to say I dislike it intensely. I believe in a real life situation getting it down on a runway in a surviveable state is very questionable. However, it is better than nothing. At least it gives you a chance. but I do think the proportion of surviveable outcomes in such events would be in the minority.

[captplaystation]

Seem to remember way way back, Brittania landing one in GLA in Man Reversion (circa 1982? ) but maybe the memory is playing tricks. Any instructor I have had in sim who has done it for real (usually on test flts) has emphasised to me that the aircraft (whilst not easy or pleasant to fly) is a few degrees easier than the sim. I have not ( I am glad to say ) had the chance to verify that. Will be interesting when the report is published to see if the reported 5000' level off is confirmed. That is TOO damn close to a smoking hole in the ground for comfort - and if they really started @ F360 well it doesn't bear thinking about.

[Centreline747]

IF this occurred during a check of manual reversion then why not just re-instate the hydraulics? (sjm - post 44 are you implying that you cant?
I have flown the 737 and as Rainboe commented the manual reversion training in the sim is horrible.
Thankfully, due to the redundancy on the 747, it doesn't have manual reversion; I'd hate to have to try and move those large controls manually, if you could at all!!

Well done to the crew whatever the situation was

Rgds

CL 747

[Centreline747]

i m l a

Thanks. I can see that happening with control input, I just wondered if, when it all began to go pear-shaped, relax the controls, apply hydraulics, and smoothly and gently recover. I wasn't there so I don't know what happened. (Gladly)
Just my thoughts.

Rgds

CL747

[kriskross]

The CAA flight test schedule, in front of me, for the -300 calls for this test to be carried out at F 350. The -700 test requires this to be done at F150, so that would be a 10000ft height loss for a 5000ft recovery

[Checkboard]

The height loss was about 10,000 feet, recovery was nowhere near 5000 AGL. The height loss was so large because you have to unload the controls in order to re-instate the hydraulics, and even with a 90 degree roll, the initial pitch has dropped the nose quite a bit. Once the aircraft is in overspeed, the the nose up recovery needs to be gentle in order to avoid a worse overstress.

[Smilin_Ed]

Always Pitch Up?

Is everyone assuming that every pitch change would be up into a stall? Could it not be down?

[Mr Good Cat]

Not meaning to drift the thread but the 737 CAN be flown with some degree of accuracy in Manual Reversion, providing you still have the standby reservoir available.

This is from both sim experience AND flight test experience. Any lack of authority from the ailerons can be supplemented with inputs from the now over-sensitive rudder. Yes, I agree that situations such as gusting crosswinds may limit controlled landing techniques but generally it's not the end of the world and it is definitely controllable with one pilot's inputs only - and this is from a puny midget!

The problems arise in scenarios like the one being discussed. A similar occurrence happened to me on a air test a few years back when I was just a wee cadet in the RHS. We took an EZY classic up over the Irish Sea west of the Hebs after a replaced elevator and switched off the flight controls, after which we experienced several seconds of weightlessness and about 4000 feet loss of altitude until we could get the switches back to their rightful positions. The elevator was only two thousands of an inch out, but this was enough to upset things in a BIG way...

[veterangreaser]

PBY
Ask the captain of the AA A320 about no engines and aircraft control! No engine hydraulics, just the blue system powered by the RAT? He seemed in full control to do such a good job! The 737 is still a great aircraft, BUT underneath the recently added "Bells & Whistles" it's still 40 year old technology.

[wkw198]

think it was US Air not American Airlines (AA)

[ciampino]

I know this is a NG but the 300 MM states DO NOT REINSTALL HYDRAULICS

[Papa Golf]

Manual Reversion sensitivity

A-Frame is correct, very small adjustments of the elevator tabs can have quite a large trim impact in manual reversion. Most common error is not a gross error as with EZY but making the adjustment in the wrong direction (the Boeing Maintenance Manual had to be followed very carefully to get it right). Some years ago have seen Boeing adjust tabs in wrong sense on new production aircraft during flight testing prior to customer acceptance.

[Fliifast1]

Hey, my company is getting a -700 from EasyJet in two weeks...I'll let you all know how she trims out. Fli

[Tee Emm]

Control forces are very high requiring both pilot inputs

According to Boeing in Seattle, there is no non-normal manoevre in the FCTM that requires the use of two pilots on the controls. If there was, three pilots would have to constitute the normal crew in case one became incapacitated. The manual reversion approach and landing is relatively straight forward to fly assuming a competent pilot is flying. Some operators prefer that one pilot flies the manual approach and the other pilot handles the power. It was this policy that aroused the ire of simulator instructors at Seattle.

Some pilots have done only one manual reversion approach and landing as part of a typre rating then never practiced one again. It is these pilots that may experience significant handling problems and then complain of the danger. One pilot can easily fly the approach and handle his own power IF he is competent. Automation complacency has a lot to answer for - especially where almost total reliance on automation has led to a class of pilots that have lost confidence in their ability to handle something like a manual reversion landing.

[Chille Con Carnie]

G-EZJK had another test flight yesterday understand no probs--- with handling?

[charliemouse]

PBY
Ask the captain of the AA A320 about no engines and aircraft control! No engine hydraulics, just the blue system powered by the RAT? He seemed in full control to do such a good job! The 737 is still a great aircraft, BUT underneath the recently added "Bells & Whistles" it's still 40 year old technology.

The first thing Sully did was start the APU - so this not relevant?

[6853]

Anything official yet?

[a300dave]

G-EZJK now reregistered and winging its way to Brazil

[Jofm5]

For those that are interested AAIB Special report into the incident is available from Air Accidents Investigation: S2/2009 - Boeing 737-73V, G-EZJK


Cheers all