ATA 52 Doors
1 - E/E door-handle not flush. 737-3/4/500
2 - Main Cargo Door MCD hydraulic filter replacement instructions see ATA 29. 737-3/400
3 - Overwing (emergency) exit door light on. (including video) 737-6/7/8/900
4 - Pax door closure inspection: door looks closed but isn't. 737-ALL
5 - Door sensor swap with gear sensor. 737-3/4/500
6 - Pax / service door adjustment guide. 737-ALL
7 - E/E door handle stuck in retracted position with closed door. 737-6/7/8/900
8 -
Cargo door handle stud missing and housing damaged. 737-ALL
1 - E/E door-handle
not flush.
737-3/4/500
Sometimes it happens that the E&E door handle will NOT stay flush with the door closed. To correct this do the following:
With the door open, turn the handle to closed position, the pins are now extending. Then push the handle flush with the door, now you can push the pins inwards. Now everything is reset and should work normal again.
3 - Overwing
(emergency) exit door light on.
737-6/7/8/900
When you get an overwing exit door light ON on the P5 overhead panel, it could be the solenoid not working correctly when commanded. Experience showed that the solenoid gets 28VDC when the emergency doors need to be locked, but that the solenoid could be a bit sticky or slow to retract (due to dirt, dust or moisture), causing the warning light on P5 to go ON. Replacing the solenoid solved the problem.
An explanation on how this solenoid moves the lock inside the exit door, is shown in this movie, and on the picture below.
5 - Door
sensor swap with gear sensor.
737-3/4/500
During turnaround the crew reported that the right main gear warning light does not come on when moving the landing gear control lever and thats a no go item due to no auxiliary down lock indicator light at the aft overhead panel. During troubleshooting found that the lock and position sensor for the right gear defective and need replacement, but no spare available at the time, so in order not to ground the aircraft and fly back to base we swapped the right gear sensor with the fwd cargo door sensor, they where the same p/n 1-899-29 and MEL the fwd cargo door warning light system (mel 52-3).
Thanks to Mohammed Mustafa.
6 - Pax
/ service door adjustment guide. 737-ALL
Sequence of adjustments:
1 - Gate pushrod.
2 - Latch-torque tube.
3 - Guidearm.
4 - Cockingcrank-pushrod.
5 - Door stops.
6 - Latchtracks.
7 - General.
1) Gate pushrod.
The gate pushrod is properly adjusted, when the gates follow the door-profile. This is best checked with the door in open position. Disconnect the latching-pushrods from the latch torque tubes. Operate the gate manually full out. Some gates have stoprods. These do not belong to the adjustment mechanism, but they
have to have the same adjustment.
2) Latch torque tube.
The latch torque tube is properly adjusted, when the gate-pushrod is just in the cocking position at the end of the travel of the door handle.
This is best checked with the door open position and cockingcrank-pushrod disconnected from the cockingcrankshaft. In this condition, the latching and gate-control mechanism can be operated without operating the door.
3) Guidearm.
The guidearm is properly adjusted if the door, just before the camplate operates the latchingcrank, is parallel to the fuselage.
In a normal condition, the door is about one to two cm inside the fuselage when the latchingcrank is operated by the camplate. If this is not the case,
adjust first the cockingcrank-pushrod.
4) Cockingcrank-pushrod.
The cockingcrank-pushrod is adjusted properly, if the cockingcrankpushrod is tensionfree installed with the door in the closed position. The bolt must be possible to rotate by hand. Also the exterior controlhandle must be operated without friction in the stowed position.
5) The doorstops.
The stops are properly adjusted, if the distance between the doorskin and the doorstop is equal to the distance of the fuselageskin and the stopfitting.
Because the fuselage skin panels overlap and are bended, and the door is not always equally curved, it will be difficult to apply this rule for all the
doorstops. Its best to adjust the stops near the latchtracks according to this rule. Thereafter, the other stops can be set if a cabin diffpressure of 1 psi
is present or through a clay test. (~ 1 mm depressurized clay-over). When the controlhandle moves during this test, the latchtracks are not adjusted
correctly.
6) Latchtracks.
The latchtracks are properly adjusted, if they are free from the latchtrack with a cabin diffpress of one to one and half psid. The door is then at the end
stops, and there are no more forces present on the mechanism and the handle can easily moved a little bit. The latchtrack is about two millimeters larger
than the roller. The clay test should show more clay leftover on the outboard side than the clay leftover on the doorstops. (Pressureless ~ two mm clay-leftover).
7) General:
When the torque tubes (or bearings) are worn or the tubes are not properly mounted, it is possible that the door is too low in the door-opening. The hingearm
plating and the snubber are then scraping in the recess. If this is not the case and the door is still too low, the door can be adjusted upwards relative to
the torque tube.
With the door closed, and at the top and bottom its not closing evenly (parralell) inside, the hingearms themselves ar not fastened enough anymore. This may
be caused by loose or worn bolts, loose guide plates or loose bearing supports. If this causes excessive force to close the door, damage may occur at the
mechanism. Often fastening of the door-torquetube bolts will help a lot.
Note that all adjustments are related to each other. This makes the adjustment of a 737 door a very difficult job, requiring experience over time. All adjustments have tolerances and it is sometimes possible to rectify a defect through the right mix of adjustments within the permitted values.
This text was written by R.Meijer in Dutch and translated in English using Google translate.
For
the Dutch version click
here.
See the pictures below for more clarification:
7 - E+E
door handle stuck in retracted position with closed door.
737-6/7/8/900
If E & E door handle is stuck in retracted position with the door closed,
possibly with a E&E door warning.
Investigations into reported E&E bay door handle anomalies and warning light
illuminations indicates that the probable cause is vibration which causes the
door latch mechanism to move toward the open position in flight. The part of the
mechanism that engages and disengages the latching pins in the handle slightly
unlatching over time. When the handle is attempted to engage with the unlocking
mechanism, it cannot because the coupling pins are not aligned. If this
misalignment is only a few degrees, it may cause the following two difficulties:
1. The door warning light to illuminate because the latch pin moves toward the
unlatched position.
2. The door may not be able to be opened because the handle will not deploy when
released and it may not be able to be pulled out. This can occur when the dowel
pins in the mechanism move from their alignment with a slot in the lower handle
shaft mechanism. If this happens, the door can not be opened from the outside.
(FTD 52-08005)
Do not force the handle out because it will break.
Remove the batteries through the fwd cargo hold, and crawl in to the E & E,
Now use a water pump plier and rotate the center shaft to unlock the door.
Thanks to Richard E. for this input.
8 - Cargo door handle stud missing and housing damaged. 737-ALL
Almost always the stud inside the cargodoor handle is
broken off in no-time. This happens on all 737 types on fwd and aft cargo door
handles. The result is a damaged (gouged) housing caused by the
handle-without-stud.
The limits of the damage cannot be found in the AMM or SRM, but in the
handle-assy-manufacturers CMM.
Since a damage that is too large can result in a cracked housing, it is
recommended that a new stud is placed inside the handle and the damage is
measured and reworked according the CMM. If the damage is too large the complete
housing needs to be replaced.
Also the removal of a broken-off stud cannot be found anywhere.
Experience learned us 3 (+1) ways to remove the broken-off stud from the handle.
These procedures are not official
and approved anywhere, but are pure practice that works ! Please send in more
possibilities if you know them !
UPDATE: Another method is used also, see option 4 !
1 - Push and simultaniously turn a parker-screw inside the
remains of the stud, as showed on the pictures. Then pull out the screw and the
stud with a pliers.
2 - A small hole is drilled from outside the handle into the
place where the stud is installed. Then a small drill or tool can be used to
hammer out the stud from the handle. This way is very fast and easy, because a
new stud will break off in no-time, so you can use this drilled hole again and
again. Note that it may not be allowed to drill a hole in the handle ! But as
you know, this website is to share such (unofficial) tips and tricks, as they
are used in everyday maintenenace. See picture.
3 - Use a heatgun to heat up the handle where the stud remains
are, and after a few minutes the stud will come out of the handle due to the
expanding air below the stud inside the handle. This way works great if you have
the tools and power supply available. No picture availabe for this one.
4 - Get a
piece of 2x4 wood board. Pull the handle out, place the 2x4 between the handle
and the cargo door to back up the handle while you hit it, leaving the stud area
clear. Then using a rivet gun with a flush set you hit the outside of the handle
right at the stud position. It will come walking right out as you hit it with
the flush set. Thanks to Tom S. for this 4th tip !
The installation of a new stud and wedge is easy, just push it in carefully.
The rework procedure and damage limits are in Hartwell CMM 52-36-15.
The newest aircraft from line No 3170 have a redesigned handle and stud, as
showed on the picture.
Refer to 737NG-FTD-52-08003 and Service Letter 737-SL-52-048.
