GRAHAM WARWICK / WASHINGTON DC
Autonomous system designed to replace lengthy manual inspection with overnight scan
Honeywell is leading a team developing a robotic system than can scan an aircraft for corrosion or other structural defects overnight and unattended, replacing a manual inspection that can take days. The company has tested a prototype of the Structural Anomaly Mapping (SAM) system and has begun validation work with the US Federal Aviation Administration.
The system is a self-positioning robotic vehicle carrying acoustic and laser sensors that can detect subsurface defects such as composite delamination and honeycomb damage, as well as corrosion and cracks. The platform has a 9m (29.5ft) mast and a 3m arm and can inspect aircraft up to Boeing 737 size. Scanning a Gulfstream V takes 10-12h, compared to 120-200h for a manual x-ray/ultrasonic inspection, says Honeywell.
The system sends a high-power acoustic wave into the structure and uses a laser beam to measure the resulting vibration of the aircraft's skin. The "ping" covers a frequency range from 4-5Hz to 40-50GHz. The lower the frequency, the further into the structure the sound penetrates before reflecting back to vibrate the skin "like a drum", says Honeywell, building up a three-dimensional image.
The SAM is programmed with a library of structural anomaly "signatures" and the digital visualisation is colour coded to highlight problem areas. Images from previous inspections can be stored and compared. The system is programmed to recognise the aircraft type and manoeuvre to inspect all or part of the airframe without touching the surface or removing the aircraft from flight status.
Honeywell is developing the SAM with BBA Diagnostics, a joint venture formed by BAA Aviation Services Group and Advanced Power Technologies. The system is due to become available in the second quarter of next year. Airlines and large fractional-ownership operators are the main customers.
The team plans to offer inspection services at major airline hubs, fixed-base operators and maintenance centres. Typically an operator would schedule a SAM scan before a major overhaul to help pre-plan maintenance. The US military is also interested, for use on older aircraft prone to corrosion and to inspect stealth aircraft without removing difficult-to-maintain low-observability coatings.
Source: Flight International
