  It has long been expected that in some scenarios when a white dwarf (WD)
grows to the Chandrasekhar limit, it can undergo an accretion induced collapse
(AIC) to form a rapidly rotating neutron star. Nevertheless, the detection of
such events has so far evaded discovery, likely because the optical,
supernova-like emission is expected to be dim and short-lived. Here we propose
a novel signature of AIC: a transient radio source lasting for a few months.
Rapid rotation along with flux freezing and dynamo action can grow the WD's
magnetic field to magnetar strengths during collapse. The spindown of this
newly born magnetar generates a pulsar wind nebula (PWN) within the
~0.001-0.1Msun of ejecta surrounding it. Our calculations show that synchrotron
emission from the PWN may be detectable in the radio, even if the magnetar has
a rather modest magnetic field of ~2*10^14 G and an initial spin period of ~10
ms. An all-sky survey with a detection limit of 1 mJy at 1.4 GHz would see
~4(f/10^-2) above threshold at any given time, where f is the ratio of the AIC
rate to Type Ia supernova rate. A similar scenario may result from binary
neutron stars if some mergers produce massive neutron stars rather than black
holes. We conclude with a discussion of the detectability of these types of
radio sources in an era of facilities with high mapping speeds.
