Tesco ML50-20 User manual

MAINTENANCE LIFT
Operator
co
Property of American Airlines

ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
ML50-20 MAINTENANCE LIFT
OPERATION AND MAINTENANCE MANUAL
WITH
ILLUSTRATED PARTS LIST
EDITION 3, JANUARY 2011
FOR USE WITH ML50-20 MAINTENANCE LIFT
Revision 8
PREPARED FOR Federal Express
SERIAL NUMBER:
14-04-11475-F-ML5020 TO 14-04-11488-F-ML5020
and up
FedEx Asset No.
502469 TO 502482
and up
MANUFACTURED BY
TESCO EQUIPMENT LLC
3661 NW 126th Avenue
Coral Springs, FL 33065
TELEPHONE: (954) 752-7994
FAX: (954) 341-3802
http://www.tescohilift.com/
January 2015
Property of American Airlines

ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
RECORD OF REVISIONS
REV.
NO.
ISSUE
DATE
INSERT
DATE BY REV.
NO.
ISSUE
DATE
INSERT
DATE BY
11/11
25/11
38/11
45/13
5 10/13
611/13
71/14
Jan. 14
81/15
Property of American Airlines

ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
LIST OF EFFECTIVE PAGES
Chapter/Section Page(s) Revison Level/
Date Shown
Cover Rev. 7 / Jan. 14
Editon Page Rev. 8 / Jan.15
Record of Revisions Rev. 8 / Jan. 15
List of Effective Pages 1 Rev. 8 / Jan. 15
1-1 2 Rev. 7 / Jan. 14
1-1 2 Rev. 7 / Jan. 14
1-2 4 Rev. 7 / Jan. 14
1-2 5 Rev. 1 / Jan. 11
1-2 9 Rev. 7 / Jan. 14
1-2 13 Rev. 7 / Jan. 14
1-3 1 Rev. 7 / Jan. 14
2-Contents 1-2 Rev. 7 / Jan. 14
2-Figures 1 Rev. 7 / Jan. 14
2-2 4 Rev. 2 / May 11
2-2 5 Rev. 7 / Jan. 14
2-5 1 Rev. 7 / Jan. 14
2-5 2-3 Rev. 6 / Nov. 13
2-5 6-12 Rev. 7 / Jan. 14
4-Contents 1 Rev. 1 / Jan. 11
4-1 2 Rev. 1 / Jan. 11
4-1 3 Rev. 7 / Jan. 14
4-4 1 Rev. 1 / Jan. 11
4-4 2 Rev. 7 / Jan. 14
4-4 7-10 Rev. 7 / Jan. 14
4-4 12-13 Rev. 1 / Jan. 11
4-4 14 Rev. 7 / Jan. 14
Jan. 14
Property of American Airlines

1-1
Page 2
TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
4-4 16 Rev. 1 / Jan. 11
4-4 20 Rev. 7 / Jan. 14
4-4 21 Rev. 1 / Jan. 11
4-4 22 Rev. 7 / Jan. 14
4-4 23-26 Rev. 1 / Jan. 11
4-4 8-9 Rev. 8 / Jan. 15
5-Contents 1Rev. 7 / Jan. 14
Chapter/Section Page(s) Revison Level/
Date Shown
Jan. 14
5-5 1-6 Rev. 7 / Jan. 14
Property of American Airlines

ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
This manual contains information for the ML50-20 Maintenance Lift and includes: general information,
operating procedures, maintenance, overhaul/repairs, and illustrated parts list.
It is a compilation of the best information available at the time of writing. Tesco strives to be the best in the
industry; however, we realize that there is always room for improvement. If you have any comments or
corrections to this manual that you feel should be addressed, please contact us by phone or fax. We will review
your suggestions promptly and take any necessary actions required to improve.
Your new ML50-20 unit’s serial number can be found on the “Serial Number/Mfg. Nameplate,” which is located
on the scissor lift unit’s lower left side frame rail.
Thank you for letting Tesco Equipment LLC serve your ground support equipment needs.
CONFIDENTIAL
THIS MANUAL CONTAINS CONFIDENTIAL AND PROPRIETARY INFORMATION OF TESCO EQUIPMENT
LLC AND CANNOT BE DUPLICATED, USED OR DISCLOSED IN WHOLE OR IN PART WITHOUT
WRITTEN AUTHORIZATION FROM TESCO EQUIPMENT LLC.
© 2008 TESCO EQUIPMENT LLC, all rights reserved as an unpublished work.
Property of American Airlines

LIMITED WARRANTY
Tesco Equipment LLC warrants to the original purchaser all Tesco equipment against defective materials or
workmanship (but not against failures or defects resulting, directly or indirectly, from accident, abuse,
modification, alteration, lack of recommended maintenance, normal wear and tear, misuse, use of parts and
components not recommended by Tesco, or use for purposes not reasonably intended) for a period of twelve
(12) months from the date of shipment to the original purchaser. The warrant of purchased functional
components is limited to that specified by the component manufacturer.
THIS LIMITED WARRANTY IS NOT ASSIGNABLE BY THE ORIGINAL PURCHASER OF TESCO
EQUIPMENT. ANY PURPORTED ASSIGNMENT OF THIS LIMITED WARRANTY SHALL BE VOID AND
TESCO SHALL HAVE NO OBLIGATION TO HONOR OR PERFORM UNDER THIS LIMITED WARRANTY IN
FAVOR OF ANY PERSON OR ENTITY OTHER THAN THE ORIGINAL PURCHASER.
Tesco will, at its sole option, repair or replace any component, part or parts, if found on examination by Tesco
to be defective and if the necessary return charges are prepaid by the original purchaser. Installation labor will
be the original purchaser’s responsibility. The above only applies to Tesco manufactured components.
Purchased components will be handled based on their individual warranties.
THIS ABOVE WARRANTY AND THE ABOVE OBLIGATION TO REPAIR OR REPLACE ARE COMPLETE
AND INCLUSIVE. THIS LIMITED WARRANTY IS GIVEN IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. ANY IMPLIED WARRANTIES, WHICH MAY BE FOUND IN
CONNECTION WITH THE PRODUCT, ARE HEREBY LIMITED IN DURATION TO NINETY (90) DAYS FROM
THE DATE OF SHIPMENT TO THE ORIGINAL PURCHASER.
THE SOLE AND EXCLUSIVE REMEDY OF ANY PERSON, AND THE SOLE AND EXCLUSIVE OBLIGATION
AND LIABILITY OF TESCO WITH RESPECT TO TESCO EQUIPMENT IS THE LIMITED WARRANTY SET
FORTH HEREIN. TESCO SHALL NOT BE RESPONSIBLE OR LIABLE FOR ANY DAMAGES, WHETHER
ARISING IN CONTRACT OR IN TORT, OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES,
INCLUDING LOSS OF USE AND LOST PROFITS, IN CONNECTION WITH THE PURCHASE, SALES,
SHIPMENT, SERVICE, REPAIR OR OPERATION OF ANY TESCO EQUIPMENT. IN NO EVENT SHALL
TESCO LIABILITY TO ANY PERSON EXCEED THE PURCHASE PRICE OF THE TESCO EQUIPMENT.
Any expense incurred without Tesco’s prior consent for repairs or replacement will not be allowed. All
modifications by the end-user must be approved by Tesco in writing in order that the expressed warranty
remain in effect.
Tesco reserves the right to make changes in design and changes or improvements upon its products without
any obligation upon itself to install the same upon its products theretofore manufactured.
Hi-Lifts with known failed or defective parts must be immediately removed from service.
This warranty requires proper and timely maintenance and periodic inspections of the Tesco Hi-Lift as
indicated in the operator’s manual furnished with each Tesco unit. The cost of routine or required maintenance
and service is the responsibility of the customer. The customer is required to keep documented evidence of
when and by whom maintenance and service are performed.
Inquires concerning this limited warranty should be addressed to:
Tesco Equipment LLC Phone Number: (954) 752-7994
3661 NW 126th Avenue Fax Number: (954) 341-3802
Coral Springs, FL 33065
Property of American Airlines

Warnings/Cautions
Page 1
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
LIST OF WARNINGS AND CAUTIONS USED IN THIS MANUAL
WARNING
A WARNING MEANS THAT A PROCEDURE THAT FOLLOWS COULD CAUSE DEATH OR
INJURY TO YOU OR OTHER PERSONNEL IN THE AREA IF THE PROCEDURE IS NOT
FOLLOWED AS WRITTEN.
CAUTION
A CAUTION MEANS THAT A PROCEDURE THAT FOLLOWS COULD CAUSE DAMAGE TO
EQUIPMENT IF THE PROCEDURE IS NOT FOLLOWED AS WRITTEN.
The following warnings and cautions are used in this manual. Read all of them and follow the instructions when
performing the procedures.
WARNING
DO NOT OPERATE THE HI-LIFT DEVICE UNLESS YOU HAVE BEEN TRAINED IN THE SAFE
OPERATION OF THE UNIT AND ARE FAMILIAR WITH THE INSTRUCTIONS AND SAFETY
WARNINGS CONTAINED IN THIS MANUAL. FAILURE TO HEED WARNINGS MAY RESULT IN
SERIOUS INJURY OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT OPERATE A HI-LIFT UNIT THAT HAS VISIBLE DAMAGE TO STRUCTURAL OR
HYDRAULIC COMPONENTS INCLUDING HOSES. FAILURE TO HEED WARNINGS MAY
RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT ATTEMPT TO STABILIZE A HI-LIFT UNIT ON SOFT GROUND OR ON INCLINES BY
SHIMMING STABILIZER’S. FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY
OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT RETRACT OR ADJUST STABILIZERS WHEN HI-LIFT UNIT IS IN RAISED POSITION.
TAMPERING WITH THE STABILIZER CONTROLS OR STABILIZERS MAY CAUSE THE UNIT TO
BE UNSTABLE. FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH
TO OPERATOR AND/OR CREW.
WARNING
DO NOT RAISE THE HI-LIFT UNIT UNLESS THE STABILIZERS HAVE BEEN DEPLOYED.
FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR
AND/OR CREW.
May 08
Property of American Airlines

Warnings/Cautions
Page 2
TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
WARNING
THE HI-LIFT UNIT AND COMPONENTS ARE NOT INSULATED AGAINST ELECTRICAL SHOCK.
ENSURE PROPER CLEARANCE AROUND THE BODY/PLATFORM AND HI-LIFT STRUCTURE.
FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR
AND/OR CREW.
WARNING
ENSURE ALL PERSONNEL ARE STANDING CLEAR OF STABILIZERS AND STABILIZER PAD
CONTACT AREA WHEN DEPLOYING AND RETRACTING STABILIZERS. CRUSHING AND/OR
PINCHING INJURY MAY RESULT.
WARNING
DO NOT ATTEMPT TO PERFORM ANY MAINTENANCE WORK OR REPAIRS ON A RAISED
SCISSOR LIFT/PLATFORM WITHOUT ENGAGING THE MAINTENANCE PROP. FAILURE TO
COMPLY COULD CAUSE DEATH OR INJURY.
CAUTION
DO NOT LEAVE WHEN HI-LIFT UNIT IS IN RAISED POSITION UNATTENDED.
WARNING
DO NOT DRIVE OR MOVE THE TRUCK IF ANY OF THE INDICATOR WARNING LIGHTS ON THE
DASH BOARD ARE LIT. SERIOUS INJURY TO OPERATOR OR DAMAGE TO THE UNIT MAY
RESULT.
WARNING
STAND CLEAR OF STABILIZERS PAD, WHILE OPERATING THE STABILIZER CONTROLS.
CRUSHING INJURY TO OPERATORS FEET COULD RESULT.
WARNING
DO NOT ATTEMPT TO RAISE THE WORK PLATFORM UNLESS THE STABLIZERS ARE
EXTENDED AND SET. SERIOUS INJURY OR DEATH TO OPEATOR MAY RESULT IF UNIT
UPSETS.
WARNING
DO NOT OVERLOAD HI-LIFT UNIT, DO NOT EXCEED THE RATED CAPACITY. SERIOUS
DAMAGE TO THE HI-LIFT WILL RESULT, WITH POSSIBLE INJURY TO OPERATORS.
May 08
Property of American Airlines

Warnings/Cautions
Page 3
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
CAUTION
MAINTAIN A SPACE OF AT LEAST 12 IN (304 MM) BETWEEN THE AIRCRAFT AND WORK
PLATFORM. DO NOT MAKE CONTACT WITH ANY PART OF THE AIRCRAFT.
CAUTION
THE HI-LIFT MUST BE PROPERLY STOWED BEFORE ATTEMPTING TO DRIVE THE VEHICLE.
INDICATOR LIGHTS WILL BE LIT IF THE HI-LIFT IS NOT IN THE STOWED POSITION. SERIOUS
DAMAGE CAN OCCUR IF THE VEHICLE IS MOVED WITHOUT PROPERLY STOWING THE HI-
LIFT.
WARNING
ENSURE THAT THE HI-LIFT IS FULLY LOWERED BEFORE ATTEMPING TO RETRACT
STABILIZERS.
CAUTION
STAND CLEAR OF DESCENDING HI-LIFT. SERIOUS INJURY TO OPERATOR MAY OCCUR IF
STRUCK BY DESCENDING LIFT.
CAUTION
DO NOT SHIP THE UNIT ABOVE DECK WHERE IT CAN BE EXPOSED TO SALT WATER.
CAUTION
AFTER PERFORMING MAINTENANCE ON THE HI-LIFT, DISPOSE OF ANY
ENVIRONMENTALLY SENSITIVE MATERIALS ACCORDING TO LOCAL ENVIRONMENTAL
REGULATIONS. EXAMPLES OF SUCH MATERIALS INCLUDE: BATTERIES, RUBBER BELTS,
LUBRICANTS (MOTOR OILS AND GREASE), AND HYDRAULIC OIL.
WARNING
THE SCISSOR LIFT MUST BE SECURED WITH THE MAINTENANCE PROP BEFORE
ACCESSING THE GREASE POINTS.
WARNING
BEFORE STARTING ANY ADJUSTMENT PROCEDURE THAT REQUIRES THE PLATFORM TO
BE IN AN ELEVATED POSITION, MOVE THE MAINTENANCE STAND INTO POSITION AND
LOWER THE PLATFORM FULLY AGAINST THE MAINTENANCE PROP.
WARNING
IT IS MANDATORY THAT EYE PROTECTION (SAFETY GOGGLES OR FACE SHIELD) BE WORN
May 08
Property of American Airlines

Warnings/Cautions
Page 4
TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
WHEN MAKING PRESSURE CHECKS AND/OR ADJUSTMENTS ON THE HYDRAULIC SYSTEM.
HYDRAULIC OIL WILL CAUSE EYE INJURIES. IF HYDRAULIC OIL GETS ON THE SKIN, WASH
AFFECTED AREA IMMEDIATELY TO AVOID IRRITATION.
WARNING
DRIVE WHEELS MUST BE CHOCKED TO PREVENT MOVEMENT OF THE UNIT IN EITHER
DIRECTION.
WARNING
WHEN MAKING PRESSURE CHECKS OR ADJUSTMENTS, USE GAUGES WITH KNOWN
ACCURACY. IMPROPER HYDRAULIC ADJUSTMENTS CAN CAUSE INJURY TO PERSONNEL
OR DAMAGE TO EQUIPMENT.
WARNING
DO NOT REMOVE GAUGE PORT PLUGS OR GAUGES, OR LOOSEN HYDRAULIC
CONNECTIONS WITH THE UNIT RUNNING. HYDRAULIC PRESSURE IN THE SYSTEMS COULD
CAUSE HYDRAULIC OIL TO SPRAY ON PERSONNEL.
CAUTION
USE EXTREME CARE TO PREVENT CONTAMINATION OF HYDRAULIC SYSTEM WHEN
INSTALLING GAUGES, FITTINGS, OR REPLACING A COMPONENT. CONTAMINATION CAN
RESULT IN EQUIPMENT DAMAGE.
CAUTION
WHENEVER AN ADJUSTABLE HYDRAULIC RELIEF VALVE OR PRESSURE REDUCING VALVE
IS REPLACED, REDUCE THE PRESSURE SETTING PRIOR TO STARTING THE UNIT. ADJUST
THE REPLACED COMPONENT TO SPECIFICATION AS OUTLINED IN THE ADJUSTMENT
PROCEDURES.
CAUTION
WHEN MAKING HYDRAULIC SYSTEM ADJUSTMENTS, THE HYDRAULIC OIL MUST BE AT
NORMAL OPERATING TEMPERATURE.
WARNING
ONLY QUALIFIED TECHNICIANS, WHO HAVE BEEN TRAINED IN THE USE AND OPERATION
OF THIS EQUIPMENT, SHOULD ATTEMPT ANY TROUBLESHOOTING. THE CHASSIS WHEELS
MUST BE CHOCKED TO PREVENT THE HI-LIFT UNIT FROM MOVING IN EITHER DIRECTION.
THE MAINTENANCE PROP MUST BE INSTALLED FOR SUPPORT WHENEVER THE
PLATFORM IS RAISED FOR MAINTENANCE OR ADJUSTMENTS. FAILURE TO FOLLOW GOOD
SAFETY PRACTICES DURING MAINTENANCE OR TROUBLESHOOTING COULD RESULT IN
DEATH OR SERIOUS INJURY TO PERSONNEL AND/OR DAMAGE TO EQUIPMENT.
May 08
Property of American Airlines

Warnings/Cautions
Page 5
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
WARNING
DO NOT ALLOW PERSONNEL UNDER THE HI-LIFT UNLESS THE MAINTENANCE PROPS ARE
IN PLACE. FAILURE TO SUPPORT THE PLATFORM MAY ALLOW PLATFORM TO FALL,
RESULTING IN DEATH OR INJURY TO PERSONNEL OR DAMAGE TO EQUIPMENT.
WARNING
USE EYE PROTECTION AND PROTECTIVE CLOTHING RECOMMENDED BY THE
MANUFACTURER OF THE WELDING EQUIPMENT THAT IS USED.
May 08
Property of American Airlines

1-Contents
Page 1
Page
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
TABLE OF CONTENTS
CHAPTER 1: GENERAL INFORMATION AND OPERATING INSTRUCTIONS
Section 1: Description
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
MAJOR COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Scissor Lift Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Telescopic Stabilizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Control Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Hydraulic System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Section 2: Operation
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SAFETY FEATURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Standard Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Safety Interlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SAFETY PROCEDURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CONTROLS AND INDICATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Dash Mounted Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Lower Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Upper Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Upper Pendant Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Stabilizer Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
HI-LIFT VEHICLE OPERATING PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Preliminary Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Driving the Vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Hi-Lift (Body) Control Station Operating Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Returning Vehicle to Normal Driving Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
MAINTENANCE PROP OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
EMERGENCY FEATURES – OPERATING PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Manual Emergency Handpump Retracting (Stowing) Stabilizers . . . . . . . . . . . . . . . . . . . . . . . 13
Emergency Hi-Lift Lowering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Section 3: Specifications
DIMENSIONS & WEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
May 08
Property of American Airlines

1-Contents
Page 2
TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
CAPACITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
MAJOR COMPONENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Hi-Lift Single Acting Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Double Acting Stabilizer Cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Section 4: Shipping
GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DOMESTIC SHIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
OVERSEAS SHIPMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Section 5: Storage
SHORT-TERM STORAGE – ONE MONTH MAXIMUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
LONG-TERM STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
May 08
Property of American Airlines

1-Figures
Page 1
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
LIST OF FIGURES
CHAPTER 1: GENERAL INFORMATION AND OPERATING INSTRUCTIONS
Section 1: Description
1-1 Figure 1 ML50-20 MAINTENANCE LIFT....................................................................... Page 2
Section 2: Operation
1-2 Figure 1 CONTROL STATION LOCATION ................................................................... Page 4
1-2 Figure 2 DASH MOUNTED INDICATORS .................................................................... Page 5
1-2 Figure 3 LOWER CONTROL STATION ........................................................................ Page 6
1-2 Figure 4 UPPER CONTROL STATION ......................................................................... Page 7
1-2 Figure 5 UPPER PENDANT CONTROL STATION....................................................... Page 8
1-2 Figure 6 STABILIZER CONTROL STATION................................................................. Page 9
1-2 Figure 7 MAINTENANCE PROP INSTALLED............................................................... Page 12
1-2 Figure 8 EMERGENCY OVERRIDE PROCEDURE...................................................... Page 13
1-2 Figure 9 EMERGENCY HI-LIFT CYLINDER LOWERING ............................................ Page 14
Section 3: Specifications
1-3 Figure 1 TYPICAL ML50-20 MAINTENANCE LIFT - SIDE VIEW ................................. Page 3
1-3 Figure 2 TYPICAL ML50-20 MAINTENANCE LIFT - REAR VIEW ............................... Page 4
Section 4: Shipping
Section 5: Storage
May 08
Property of American Airlines

DESCRIPTION 1-1
Page 1
ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
CHAPTER 1: GENERAL INFORMATION AND OPERATING INSTRUCTIONS
Section 1: Description
1. DESCRIPTION
The Tesco ML50-20 Maintenance Lift is designed to maintain and inspect aircraft.
The ML50-20 is a scissor hi-lift unit mounted on a commercial truck chassis with a minimum gross
vehicle weight (GVW) rating of 14,500 lb (6577 kg). The work platform operates from a minimum of 52.5
in (1.33 m) floor height up to a maximum 228 in (5.8 m) floor height. The maximum payload capacity is
3,000 lb (1361 kg).
The ML50-20 is designed and manufactured in full compliance with existing ANSI/SIA A92.2-2001,
ANSI/SIA A92.7-1998, SAE and OSHA safety standards.
2. MAJOR COMPONENTS
A. Chassis
Any commercially available truck chassis that meets the Gross Vehicle Weight (G.V.W.) rating,
and 120” of Cab to Axle (CA) dimension requirements can be used.
NOTE: Refer to the chassis manufacturer’s manual for further information.
B. Scissor Lift Unit
The ML50-20 consists of two single acting (power up/gravity down) telescopic hydraulic cylinders.
Each of the two (2) hydraulic cylinders is equipped with a positive locking safety holding valve,
which will stop and hold the hi-lift in a raised position.
C. Platform
The platform’s floor surface consists of grating. Three (3) safety harness restraint D-rings are
mounted in the floor. The folding side and socket mounted end safety handrails are 41 in (1.04
m) high and constructed of structural steel tubing. The platform has 99 ft2 (9.2 m2) of working
surface. The perimeter outside edges are fitted with non-marking rubber bumpers to protect the
aircraft from any inadvertent contact.
D. Telescopic Stabilizers
Four (4) double acting telescopic stablizers are mounted to the lower scissor frame, two (2) on the
front of the frame and (2) on the back of the frame. The stabilizers are designed to deploy straight
down via double acting, hard industrial chrome-plated hydraulic cylinders, which are mounted
inside the stabilizer leg housing. Each stabilizer is equipped with a double, pilot operated safety-
holding valve, which safeguards the stabilizers from inadvertently retracting after being set or
extending while driving the vehicle.
NOTE: The Telescopic Stabilizers are not designed to lift the entire vehicle’s weight from the
ground. The stabilizers are designed to work in conjunction with the vehicle chassis
suspension during hi-lift operation.
May 08
Property of American Airlines

GENERAL INFORMATION AND OPERATING INSTRUCTIONS
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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
Figure 1
ML50-20 MAINTENANCE LIFT
SCISSORS
PLATFORM
TELESCOPIC
STABILIZERS
STEPS
CHASSIS LOWER CONTROL
Jan. 14
Property of American Airlines

DESCRIPTION 1-1
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
E. Control Stations
Four (4) control stations operate the Hi-Lift functions.
The lower control station is located on the driver side forward chassis frame. It is equipped with
three (3) push buttons to operate the hi-lift up and down functions, and a beacon switch. It also
contains a mushroom head emergency stop switch.
The two (2) upper control stations are located at the forward left corner of the platform. One
upper control is mounted on a pedestal and equipped with rotary type switches to operate work
lights, remote engine stop and start, and compressor off and on, and a mushroom head
emergency stop switch. Another upper control is pendant type enclosure. It is equipped with three
(3) push buttons to operate the hi-lift up and down functions and a mushroom head emergency
stop switch.
The fourth control station operates the stabilizers. The stabilizer control station is located on the
driver side center chassis frame. It is equipped with two (2) momentary push buttons to retract
and extend the stabilizers. The stabilizers must be extended before the platform can be raised.
The dash inside of the cab also has indicator lights for lift and stabilizer functions.
F. Hydraulic System
The hydraulic system supplies the actuating power to the stabilizers and hi-lift. An arrangement
of valves regulates fluid flow from the engine-driven pump to the actuating cylinders during
operation. An adjustable relief valve controls the system pressure, and restrictor valves regulate
rates of flow. Load holding valves prevent retraction of the platform lift cylinders and the stabilizer
cylinders if power is lost. The electrical system actuates the solenoid valves. See Chapter 2,
Section 5 for schematic diagram.
G. Electrical System
The electrical system provides control circuits for the hydraulic system, chassis interface, and
lighting. The chassis electrical system supplies system power. Manual switches permit operator
control of the system. Inter-connected limit switches and relays assure proper operational
sequence. Circuit breakers protect the system from overloads. See Chapter 2, Section 5 for
schematic diagram.
May 08
Property of American Airlines

OPERATION 1-2
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ML50-20 MAINTENANCE LIFT TESCO EQUIPMENT LLC
Section 2: Operation
1. GENERAL INFORMATION
“Safety First!” is the motto at Tesco; therefore, the first part of the Operation section begins with safety
features and procedures. Operation of the Tesco ML50-20 Maintenance Lift should not be conducted
until the operator is familiar with all the safety features and procedures associated with the ML50-20
Maintenance Lift. It is strongly advised that this manual be read completely prior to operating the vehicle.
WARNING
DO NOT OPERATE THE HI-LIFT DEVICE UNLESS YOU HAVE BEEN TRAINED IN THE SAFE
OPERATION OF THE UNIT AND ARE FAMILIAR WITH THE INSTRUCTIONS AND SAFETY
WARNINGS CONTAINED IN THIS MANUAL. FAILURE TO HEED WARNINGS MAY RESULT IN
SERIOUS INJURY OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT OPERATE A HI-LIFT UNIT THAT HAS VISIBLE DAMAGE TO STRUCTURAL OR
HYDRAULIC COMPONENTS INCLUDING HOSES. FAILURE TO HEED WARNINGS MAY
RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT ATTEMPT TO STABILIZE A HI-LIFT UNIT ON SOFT GROUND OR ON INCLINES BY
SHIMMING STABILIZER’S. FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY
OR DEATH TO OPERATOR AND/OR CREW.
WARNING
DO NOT RETRACT OR ADJUST STABILIZERS WHEN HI-LIFT UNIT IS IN RAISED POSITION.
TAMPERING WITH THE STABILIZER CONTROLS OR STABILIZERS MAY CAUSE THE UNIT TO
BE UNSTABLE. FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH
TO OPERATOR AND/OR CREW.
WARNING
DO NOT RAISE THE HI-LIFT UNIT UNLESS THE STABILIZERS HAVE BEEN DEPLOYED.
FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR
AND/OR CREW.
May 08
Property of American Airlines

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TESCO EQUIPMENT LLC ML50-20 MAINTENANCE LIFT
WARNING
THE HI-LIFT UNIT AND COMPONENTS ARE NOT INSULATED AGAINST ELECTRICAL SHOCK.
ENSURE PROPER CLEARANCE AROUND THE BODY/PLATFORM AND HI-LIFT STRUCTURE.
FAILURE TO HEED WARNINGS MAY RESULT IN SERIOUS INJURY OR DEATH TO OPERATOR
AND/OR CREW.
WARNING
ENSURE ALL PERSONNEL ARE STANDING CLEAR OF STABILIZERS AND STABILIZER PAD
CONTACT AREA WHEN DEPLOYING AND RETRACTING STABILIZERS. CRUSHING AND/OR
PINCHING INJURY MAY RESULT.
WARNING
DO NOT ATTEMPT TO PERFORM ANY MAINTENANCE WORK OR REPAIRS ON A RAISED
SCISSOR LIFT/PLATFORM WITHOUT ENGAGING THE MAINTENANCE PROP. FAILURE TO
COMPLY COULD CAUSE DEATH OR INJURY.
CAUTION
DO NOT LEAVE WHEN HI-LIFT UNIT IS IN RAISED POSITION UNATTENDED.
2. SAFETY FEATURES
A. Standard Features
• Headlights
• Combination tail and stoplights
• Back up lights
• Turn signals and hazard warning
• Parking brake
• Emergency lowering
• Handrails around platform
• Maintenance prop for maintenance access beneath platform
B. Safety Interlocks
• Stabilizers and hi-lift will not operate unless the transmission shift lever is set on neutral or park
and the parking brake is on.
• Stabilizers cannot be retracted unless the Hi-Lift is fully lowered.
May 08
Property of American Airlines
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