B737 QRH type Incidents that could be useful training discussion points.

[Centaurus]

In another thread in Tech Log, I requested Pprune readers experiences of tail pipe fires. Besides increasing my own knowledge by learning from the experience of others, the Tail Pipe Fire discussions have proved a fertile subject for simulator briefings.
I don't want to stretch the friendship too much, but I would greatly appreciate details of the following non-normals you may have struck while operating various marks of the B737. Again, this information will used as hand-outs for pilots undergoing simulator training.
A System Failures. (have known of two in one airline I worked for)?
Hot brakes and how did it occur?
Auto Speed Brake failure to operate immediately on landing (wet runway?)
Compressor Stall - ground or in flight and action taken?
Engine failure (Severe damage).
Uncommanded rudder movement or Kick back.
That will do for a start - and thanks in anticipation of a few replies.

[stator vane]

after flying on the various beasts of the 737 tree since 1992---

i have to really think hard to remember any time i have had to use the QRH "in anger" as the irish would say.

once as first officer on a 200 cargo combi, we had an oil filter bypass light---captain reacted slowly because he didn't want the passengers to feel any adverse yaw whilst shutting down the engine (and he didn't want to return to Bethel), so by the time we shut it down and completed the checklist, we were closer to anchorage. heard later that it was indeed an actual blockage of the filter by metal bits of the engine starting to eat itself. only a slight vibration as we reduced the thrust. all else was smooth as silk.

other than that, i think the only thing that caused a real use of the QRH was a double pack trip climbing out of Reno, Nevada and a picture screen failure on the first officer's side. (funny--now that i remember--same first officer). they would not reset, so we turned back to the airport of departure. low enough and quick enough to where we didn't even get close to the rubber jungle. as to the screen failure, i initially told the first officer to keep flying--he could look at my screen!! ha. but it was cavok though night and i finally took the airplane and landed. mx simply reracked the box down stairs and it worked like a charm for the next flight to IAD.

and that is the beauty of the beast. over 10800 hours on the beast and i must dig deep to pull up any QRH items.

as for the simulator sessions!! bloody hell, it could make someone want to quit flying!! the flight controls is the most complicated in my opinion and has gone through some interesting changes over the years. very easy to get tied up into an incorrect checklist there.

great airplane--the real QRH's on the airplane might have spiders living in the rings.

[Centaurus]

Thanks for that reply. I was a bit surprised there were no other replies. Looks like a dead subject...:ugh:

[ray cosmic]

I flew the aircraft for 3500 hrs and never had to take out the QRH... Its simply a great aircraft!

[alexban]

Well, hot brakes on a -300 after a high speed reject, and a long taxi to the apron resulted in fuse plug melt and damage to brake assembly.
The reversers were not used (don't remember if innoperative at the time ) and the crew did not use the brake cooling schedule from the QRH untill on arriving on the apron,.which proved to be too late.
Sys A hydraulic failure ( hydraulic liquid leaquage ) and also eng oil lost (on different flights ) presented no problems to the crew.
Other than that ,no case of major sys failure that I know of ,in more than 10 yrs of operation with the 737.

[exeng]

Although not on your list I've experienced these:


1)Cabin Alt warning horn - see the cabin alt moderately rising - carried out unscheduled pressurisation change to no avail - the cabin was now approaching 13000 ft so carried out the rapid depressurisation QRH which resulted in an emergency decent. The cabin did not reach 14000 ft so we did not deploy the pax oxygen.

The descent took us into extremely heavy rain and turbulence (operating in the tropics) as we had not seen on radar what we were decending into (set 1 deg or so down) I had not thought to re look further down with the radar as I was somewhat distracted by the events with the cabin pressure and the subsequent emergency decent.

Comms were a problem as ATC did not initially understand what our problem was. Probably wrongly in hindsight I initially called a PAN before I decided to execute an emergency decent - this just confused everything as ATC did not seem to understand what a PAN was. I issued a MAYDAY shortly before the emergency decent which was understood.

Returned to departure airport but before landing consideration had to be given whether to land overweight or not. As no emergency now existed I elected to extend gear and speedbrake 30 mins out to achieve MLW.

Incidentally the problem was eventually traced to a crack on the cross body duct supplying the packs. It took about 5 days to find this because this part of the duct was apparently hidden.


2)Loss of generator - start the APU which then failed - followed by divert.


3)Various other small QRH items not worth discussing.



Regards
Exeng

[TolTol]

Nice topic, would like to read more...

[Centaurus]

To get the subject jogging along:
In cruise 600 miles after take off noticed the oil contents gauge needle showed one gallon. Needle slowly reducing towards zero contents. As destination also 600 miles ahead over water, decided to return to base.

Visual observation of No 2 engine revealed trickle of oil. Closed down the engine and with fuel not a problem left max cruise power on remaining engine and descended at 250 knots until stabilised around 13,000 ft. Cause was incorrectly fitted O Ring to oil filler cap. Loss of oil contents confirmed and seems that this sort of problem occurs shortly after take off but for some reason we (I) never noticed until in the cruise.

Saw same type of problem while dead heading in a 737 and invited to jump seat when I spotted the low oil contents and the crew hadn't. In this case incorrectly fitted oil cap.


While positioning downwind for visual circuit noticed the park brake light on. Gear was up. Although the park brake light was not part of the "Lights Test" system (it is press to test), F/O suggested we try the Lights Test switch. We flicked the switch to test and back to bright and lo and behold the Park Brake light extinguished. Unable to explain that one.


Took over from crew who flew the aircraft Manila to Guam. They originated at HKG where scheduled servicing had taken place. On the walk around I checked the brakes for heat. Three brakes only warm (Guam has a long runway so didn't expect hot brakes) but the 4th brake cold. Disregarded this as a bit unusual but no suspicion of anything really wrong. Two hours later landed at short runway in Micronesia (Ponape). Used relatively minor braking but lots of reverse. During walk around prior to departure (45 minutes turn around) checked brakes and same result. Three warm brakes and one cold.
Another two hour leg and landed on Nauru (5600 ft long) and used moderate braking and full reverse as normal. Three brakes definately warm now and one stone cold. Maintenance discovered the cold brake hydraulic lines had been blocked off during servicing at HKG and not reconnected.

[flightleader]

Centaurus,

Just curious,why descend at 250kts with one engine until 13000ft? Would you want to get there sooner with 300kts or 320kts?

Had 6 flaps related faults upon approach. IMHO,best thing to do is recycle flap lever,if no good,select to a smaller flap setting(as per split flap checklist) go somewhere to hold,wait at least 2 mins before proceed further into the checklist.Somehow after a short wait,the split protection hydraulic cutout resets
itself and you will see the flaps retract to the smaller position(if the drives are ok).Then reselect flap as schedule,99% normal config for landing.:p

[Centaurus]

Centaurus,

Just curious,why descend at 250kts with one engine until 13000ft? Would you want to get there sooner with 300kts or 320kts?


You are probably right. It was a long time ago and on reflection it may have been a compromise between a true drift down (no hills - no problem) and a "comfortable" speed. I am rationalising a bit, here! ;)

[guidavide]

Flew the aircraft (3-4-8) for the last six years, here's my ten cent:

- Loss of HYD SYS A on short final (<1500ft AGL), completing LG extension qty dropped to 5 and pressure lost (leak in the nose gear extend line), a/c was already configured with landing flaps, by recall I selected (as PM) Flt Cont switch to STBY RUD, deselected autobrake and selected ALTN NWS as the option was fitted on the a/c; decided with F/O to continue for landing. Normal landing but upon vacating the runway we discovered that even with NWS ALTN selected only the rudder pedal steering was available and the tiller was stuck; completed rwy exit from high speed twy and called for tow to reach the stand.

- RH main gear uplock failure, rh gear was very slow retracting and when depressurizing the system with the LG lever in OFF the wheel was falling down. Considering the short flight (1 hr) and no fuel problems we continued to destination with the wheels held up with LG lever in UP position. As an extra precaution we maintained the speed below the LG extend limitation.

- Flying out with a new fitted generator climbing to cruising altitude the low oil pressure light started to come out (initially only flickering when encountering light turbulence); started the APU and disconnected generator, on the ground techs found out that the o-ring of the oil servicing cap was incorrectly fitted and oil was slowly leaking out.

That's what I recall at the moment, anyway a VERY nice and sturdy aircraft!

Davide

[Centaurus]

During middle of take off run in a 737-200, the No 2 EPR went to 2.30 while No 1 EPR stayed steady at 2.15. Both N1 stayed steady at around 100%. F/O called "overboosting" and tried to drag No 2 thrust lever back from under my hand. Told him to set 100% N1 both engines and disregard EPR. He still tried to drag No 2 thrust lever back but as I had firm grip on thrust levers he didn't get far thank goodness. As OAT 30 C it wasn't Pt2 tube icing but later discovered blocked tube due insects and other sticky material.

[FMC OVERHEAT]

-Same as guidavide L/G incident but happened for left gear. We kept the lever in the UP position having the red light on. but then after putting the lever in OFF the light extinguished. So eveything went back to normal.
-Had some problems with FMC nav database. Right after T/O, had FMC Fail on both CDU which were completly stuck. No LSkeys were responding.Started APU, connected it on one bus, and thank god for that quick electrical disruption we recovered the FMC and both CDU's. It worked like magic !
Had that happening twice.
-Problems with Flaps, Couldn't extend past 25 Max. When you select 30 you have 25 indicated. Landed with existing flaps which were past 15.
-Shortly after starting descend, we noticed the CPCS controller was messing things up, at FL100 the controller was pressurizing and cabin alt reached 1500 ft below field elevation, tried STBY, and both MAN AC and DC modes, No luck.
The Outflow valve was not responding to imputs from the panel. We concluded there was a blockage (probably mechanic) and decide to land anyways. During Taxi-in, I played again with Valve sw in MAN mode and finally succeeded to open it. After landing, we checked the outflow valve and since it was a long flight (5h leg) in cold ISA, the ouflow valve surrounding was all frozen. It was indeed a blockage of the valve because it was freezed. The Heater Gasket for the ouflow valve was found to be inop.
-Some other QRH checklist, happening often like EQUIP cooling off...
Some skippers that were working here suggested we don't do sim anymore since we're having failures for every flight. :ugh: :mad:

[db16]

Antiskid inop light illuminated at 70kt+ at night from Corfu. Both of us elected to continue. QRH not much help, but the vol 3 (performance) said to take longest available runway and land at lowest mass so as to use min brake. Dest was scheduled to be BRS. Tankering too!! Ended up at STN much to chagrin of the FOD. An electrical fault was found:confused:

[Tee Emm]

The above information is just the type of experiences that pilots new to the 737 need to study. I wish more pilots would contribute to these pages because what you have written so far is invaluable. Please don't abandon the stories simply because only a few have written in so far. For those who have done so, thank you.:ok:

[tonker]

I had both trim wheels fall off, as the retaining knut had not been fastened on properly at my end after recent maintenance. Used fire axe to whack mechanism back in, and then 50 pence to tighten the now found lost nut. To say i was a bit alarmed at holding my trim wheel in front of my face at 37k is an understement.:}

[Checkboard]

Had a Number 4 "eyebrow" window fracture, requiring a descent to reduce psi and continued to destination. It let go with a small bang, and it took about a minute to determine the cause - a minute to look up that is :)

Saw some arcing in the number two window - the left DV window next to me. It looked like a glowing expanding circle, as though someone had touched a lit cigarette to tissue paper. Reached up and turned off the window heat, but a small bubble formed in the acrylic layer and the window fractured about 10 seconds later, with a bang. The checklist had changed by this time requiring an immediate landing instead of a psi reduction.

Had a right Wing/body overheat light. Shut off the bleed, as per the QRH and the light extinguished. Called the company to see if they wanted a return or continue, and continued to destination where we expected a long delay as the bleed valve was lockwired shut to comply with the MEL. On arrival, the engineer said he would just MEL the Wing body overheat warning system, pull the circuit breaker and release us!!!!! Took a few minutes to convince him how stupid that would be. :mad:

I think all the other stuff wasn't Tech related though.

P.S. I've also noted a largish puddle of oil under the engine, and called out the engineers. When I wandered down to see them they were scratching their heads next to the open cowl, until I pointed out the oil cap wasn't secured properly - which seems quite a common problem.

Also arrived at destination, and then noted two open (empty) cans of hydraulic fluid sitting in the hydraulic bay, with the refill tube hanging out of one of them. Kicked the FO for his poor walkaround and flew back with lowish hydraulic qty in Sys A.

[Centaurus]

Over a six month period we experienced severe nosewheel shimmy in two of our B737-200's equipped with the gravel-protect sledge adjacent to the nosewheel. I saw one 737 touch down and the severe shimmy fractured both nosewheel tyres with the landing run completed on the rims.

My event started shortly after opening the thrust levers for take off when a really bad shimmy started at 30 knots, then a big bang in the vicinity of the nosewheel with loss of directional control and various hydraulic caution lights. Stopped on the runway and found that the hydraulic lines had fractured and the scissors link broken. Another company had experienced similar problems with nosewheel shimmy in the -200 and it was discovered that if you gave the noswheel steering a quick "tweak" as soon as the shimmy occurred, you could stop the shimmy for a few seconds. It was a long time ago and I don't recall the final rectification that fixed the problem although I vaguely remember something to do withy faulty batch of re-treaded nosewheel tyres.

[framer]

Great thread,
any more stories since sept 2007?

[Kempus]

737NG

After push back and checks completed illumination of Mach Trim Fail. Completed QRH and whith quick look at MEL as still on the ground it was ok to go with obivous precautions.

On requesting to continue taxi Speed Trim Fail light illuminated, again completed QRH and another quick look at MEL and was good to go.

I was flying so on line pushed TOGA and off we went. At Vr I pulled back and at that moment I lost my FD pitch bar and speed limit flag on my PFD and another master caution this time with Auto Slat Fail illuminated.

Reset the caution and continued the climbout and at N1 tried to engage Cmd B but it wouldn't engage so selected Cmd A and with flaps up into the QRH all whilst continuing with the SID. Whilst passing trhough FL080 my IRS decided it had too much and my PFD an ND went blank, A/P kicked out and was trying to fly and standby instruments. Eh you have control Capt!

We had already made the decision to return with the master caution after take-off since we now had 4 failures and more occuring.

Anyway upon landing and the enginneers coming onboard it was discover that the problem was due to one of the SMYD computers and was having clitches before take-off and according to the bite test failed at point of rotation.

What we learned from the event was that with the multiple failures was not to treat them seperatley and look at the bigger picture. Really comes down to keeping up with the tech side of flying and have since regularly went into the books to keep fresh.

[Z-526F]

Had an IRS #1 fault early this morning.

On the previous flight the named IRS was a bit slow during alignment (circa 15sec behind IRS #2, never seen before, IRS`s are coming "on-line" almost simultaneously), then we had a FAULT during alignment next day, we gave it another try, now successful. And then, 1,5hrs into the flt, my EADI and EHSI went blank, A/P off, QRH actions (recovery to ATT mode) were unsuccessful. We switched the IRS instrument transfer switch to Both on R, descended below RVSM (no A/P) and landed at destination.

Next time I`ll be more cautious when IRS will be a bit slow on start-up :sad:

Otherwise never had a single significant problem on the lovely Fat Albert :D

[Danil]

On the 300, I had to ferry the plane from a secondary airport to the main one during the night after a I had a 2 sector commercial flight.The plane completed some tech work and released for flight few minutes before I arrived to pick it up. I did the walk around and nothing has been noticed. The flight was really short, the airports being 6 NM apart, and planed to be flown at 3000 ft with flaps 5. As I was PF (from LHS) I have started to level off at 3000 ft when the F/O called out the altitude mentioning that I was climbing thru 3000 ft and speed was increasing. According to my instruments everything was fine but after a quick cross check with stby instruments we realized that the F/O indications went crazy. I called for recall items “unreliable speed” followed by the QRH but it meant nothing more than deciding that my instruments were correct, no icing present and we carried out the app and landing without any event.
After landing and snag reported the technicians discovered a white plastic ring on the F/O pitot tube. Later we learned that they were using 737 NG pitot covers on the 300. The 300’s pitot tube is larger and has specific shape and hence a specific cover. The NG cover has a plastic ring to sty fit with the tube and somehow, on that night, when the technicians removed the pitot tubes covers they tookoff the cover but the ring remained stuck there clogging the small static holes.

[Grond]

737-800 (with 'throttle-by-wire')

Idle descent in unusually low OAT.
Intermediate level off. One engine throttles up, other just sits there at flight idle. No warning lights, no nothing - just don't work!

Apparently due to ice in pressure sensing line (PS3). Came good when we descended further.

Could ruin your day if it happened to both engines :)

[stator vane]

you simply forgot the carb heat!!!! ha!!

but really, might consider a more gradual descent, using V/S. not as green but keeps the engine parameters a bit higher.

i never let the engines idle for any long period, especially up high.